THE LIBRARY OF YORK UNIVERSITY Date Due su MAY 61986 T i . SOiL MAY -91986" rjOf 3'0 1995 ^^'Cit LKecd ' ^ 3 ;995 STEAf. NOV '?0.W5? UMl t^fSU FEB 2 0 19 'm 7 T 1993 STDi lftW^6 — !997 sTim im 2 ] 2Q02 ffTBW JAN 3 1 2006 APR 1 8 1993 st W; Digitized by the Internet Archive in 2014 https://archive.org/details/greatapesstudyofOOyer[< The Qreat ^pes A STUDY OF ANTHROPOID LIFE PUBLISHED ON THE LOUIS STERN MEMORIAL FUND The (^reat ^ylpes A STUDY OF ANTHROPOID LIFE PROFESSOR OF PS YCHOBIOLOGY IN YALE UNIVERSITY THE GREATEST THING A HUMAN SOUL EVER DOES IN THIS W^ORLD IS TO SEE SOMETHING, AND TELL WHAT IT SAW IN A PLAIN WAY. HUNDREDS OF PEOPLE CAN TALK FOR ONE WHO CAN THINK^ BUT THOUSANDS CAN THINK FOR ONE WHO CAN SEE. TO SEE CLEARLY IS POETRY, PROPHECY, AND RELIGION, ALL IN ONE. BY ^^jJ- ^. Yerkes AND ^da W. Yerkes JOHN RUSKIN • MODERN PAINTERS lS[ew Haven • Yale University Tress LONDON • HUMPHREY MILFORD • OXFORD UNIVERSITY PRESS 1929 COPYRIGHT 1929 BY YALE UNIVERSITY PRESS PRINTED IN THE UNITED STATES OF AMERICA TO ROBERTA WATTERSON YERKES AND DAVID NORTON YERKES THIS PRODUCT OF OUR LABORS IS AFFECTIONATELY INSCRIBED WITH FAITH IN THEIR ABILITY TO CARRY FORWARD THE WORK WHICH FOR A SEASON WAS COMMITTED TO US PREFACE PREPARATORY to systematic and long-continued utilization of anthropoid apes as objects of psychobiological research, we have catalogued, digested, abstracted, and, as necessary, translated the literature of anthropoid life. Our files are useful aids to the investigator who may be at hand to consult them. This volume is our attempt to share our laboriously achieved informational re- sources with all who may wish to acquaint themselves generally with the subject, to study aspects of it intensively, or to consult the relevant literature. Only inciden- tally does the volume support theses or present hypotheses; it is offered, in the dis- interested spirit of science, to promote knowledge and enlightenment through the encouragement of honest, painstaking, unprejudiced observation. Included among anthropoid apes, in this volume, are the Hylobatidae (gib- bons and siamangs). If we were beginning our task anew, we should consider only the three types of great ape: orang-outan, chimpanzee, and gorilla, for whereas they are strikingly alike structurally and psychobiologically, the Hylobatidae dif- fer conspicuously from them. Moreover, all things considered, the great apes stand nearer to man, and the gibbons and siamangs nearer to monkey. We should not ac- tively quarrel with the taxonomist concerning the inclusion of the Hylobatidae among anthropoid apes, but without hesitation we should omit them, because they differ so markedly from orang-outan, chimpanzee, and gorilla. The plan of our book is evident from the Table of Contents and we would here merely comment on certain of its features. An introductory historical part was clearly indicated as desirable; so also, in our opinion, was the separate considera- tion of each anthropoid type. By devoting parts of the volume to gibbon, orang- outan, chimpanzee, and gorilla, respectively, we hope that we have succeeded in avoiding confusion of types and in achieving definiteness and legitimate sharpness of descriptive contrast. In each part materials have been arranged topically, but the categories used and their order vary somewhat for the several types of anthropoid ape. Since func- tional expressions of the organism are our primary concern, morphological descrip- tions and references, except as necessary for orientation of the student of psycho- biology, have been omitted. Authorities have been cited freely and wherever feasible quoted literally or in free condensed translation. This has considerably increased the length of our expo- sition, but it should also render it more valuable historically and more accurate. To avoid a polyglot text we have quoted only in English. Originally projected as an objective historical account of knowledge of anthro- poid life, the manuscript tended to become increasingly critical and original as we proceeded with its preparation. The first two parts — History and Gibbon — are al- most wholly historical digests. In them the authors appear as expositors, not as in- vestigators. In the Orang-outan, we quite unintentionally departed from our chosen method because our acquaintance with the type constantly tempted us to supple- X A STUDY OF ANTHROPOID LIFE ment the literature and to react to available materials critically and constructively. We departed still further from our ideal of objectivity and aloofness in the Chim- panzee. This was inevitable, since our opportunities for acquaintance with the characteristics of this ape are equaled only by those of Kohler. Furthermore, and unfortunately for us, most of our recent observations on the chimpanzee, and in- deed the major part of the results which have been obtained in the Primate Labo- ratory of Yale University during the past four years, at the time of writing, were unpublished. Finally, in case of the Gorilla we found ourselves the sole possessors of intimate acquaintance with the animal as subject of psychobiological experi- ments and therefore under necessity of writing chiefly from the point of view of our own observations. Nevertheless, this work in intent is primarily historical and objective; sec- ondarily, it is original and critical. Thus it is offered as an informational and biblio- graphic source for investigators, students, and lay readers whose curiosity may lead them into the paths of anthropoid life. Our task proved unexpectedly complex, long, and difficult. Had we realized in advance how much time it would require and how long it would interrupt our ex- perimental work with the anthropoid apes, we probably should not have under- taken it. Now that it is finished, we are relieved but also oppressed by a sense of inadequacy, for we realize how much better we could do in repetition. We dare not hope the work is free from serious errors, although every effort has been made to achieve accuracy as well as adequacy in statement, reference, and quotation. Initially personal need impelled us to assemble titles and abstracts. For aid in the early stages in this task we are indebted to Miss Geraldine Stowell, who for several months assisted us in Washington, D. C. The work thus begun subse- quently was carried forward, extended, and completed in New Haven during three years of strenuous endeavor by Miss Margaret S. Child, now Mrs. George A. Lewis. For bibliographic search, verification of records, abstracting numerous con- tributions and translating into English such French and Latin publications as were needed for our files or for quotation in the text, we make grateful acknowledgment to Mrs. Lewis. Without her efficient, skilful, technically admirable and ready ability, the completion of this work would have been long delayed even if its quality were not impaired. We cannot adequately express our gratitude for the cooperation of Mrs. Lewis or our admiration for her professional competency and the quality of her work. For translations from the Spanish and Italian, unless otherwise credited, we indicate at once our indebtedness and gratitude to Miss H. Irene Corey and Dr. Donald K. Adams. Ada W. Yerkes abstracted many of the Dutch, German, and Latin contributions. She is responsible also, unless otherwise indicated, for all translations from the Dutch and for many from the German and Latin which we have quoted. In the preparation of manuscript and illustration copy we have been greatly assisted by Mrs. Lewis, but to our secretarial helper, Mrs. Helen S. Morford, we are above all indebted for extremely accurate transcription of dictation and notes, copying, endless verification and checking of translations, quotations, titles, and PREFACE xi references, the critical correctional reading of manuscript, what seemed like inter- minable proofreading, and assistance in the preparation of index. Obviously we are deeply indebted to the scientific resources of the world and to investigators, not only of our own day but throughout human history. Yet to our friends and colleagues in anthropoid research, and especially to Mrs. N. Kohts of Moscow, Doctors A. Calmette and R. Wilbert of Paris, Doctor J. H. McGregor of New York, Doctor Gerrit S. Miller, Jr., of Washington, Sir Arthur Keith of Lon- don, Doctor E. Reichenow of Hamburg, and Doctor W. Kohler of Berlin, our obli- gations are most numerous and important, and we therefore attempt thus to indi- cate our consciousness of the fact, our appreciation and gratitude. Authorities of many of the leading zoological gardens of the world have gen- erously cooperated by supplying us with information and advice. Because of the preeminent value of their assistance we especially mention and return thanks to Director C. Emerson Brown and Doctor Herbert Fox, of the Zoological Garden of Philadelphia; Superintendent R. I. Pocock and Doctor P. Chalmers Mitchell, of the Zoological Society of London; Doctor Ludwig Heck, of the Zoological Garden of Berlin; Doctors William T. Hornaday and W. Reid Blair, of the Zoological Society of New York; the late Mr. N. Hollister, of the National Zoological Park, Washington, D. C; Doctor A. S. Le Souef, of Sydney; Doctor C. Kerbert, of Amsterdam, and Doctor J. Buttikofer, of Rotterdam. Our large collection of still and motion pictures of anthropoid apes has been importantly supplemented and the value of the illustrations in the book thus greatly enhanced through the kindness of Messrs. F. W. Bond, of the Zoological Society of London; E. R. Sanborn, of the Zoological Society of New York; Newton Hartman, of the Zoological Garden of Philadelphia, and G. Krause, The Hague. From each of these experts in animal photography we have borrowed incomparably interesting and scientifically valuable photographic copy. It is a pleasure to ac- knowledge their courteous cooperation as well as their skill and generosity. For illustrative material we desire to make acknowledgment also to Mrs. Rosalia Abreu, Doctor Harold C. Bingham, Doctor Louis Boutan, Mr. J. L. Buck, Miss Alyse Cunningham, Mr. Herbert Lang, Mr. N. E. Lewis, Dr. G. Elliot Smith, Mrs. R. A. Spaeth; American Museum of Natural History, New York; Century Com- pany, New York; Bibliographisches Institut, Leipzig; Julius Springer, Berlin; Ox- ford University Press; Societe Linneenne de Bordeaux; Natural History Society of Bombay; Museum d'Histoire Naturelle, Paris; and the editors and publishers of Comparative Psychology Monographs, Genetic Psychology Monographs, and the Proceedings of the Zoological Society of London. Naturally our historical research has depended primarily on library facilities and resources. It is indeed a pleasure to state that the intelligent, efficient, and cheerful cooperation of the staff of the Library of Yale University has set for our experience a new standard of library service. Emphatically we are appreciative of this assistance and of the spirit in which it was rendered. If we feel any regrets be- cause of the completion of our prolonged historical research it will be on account of the partial, and we hope temporary, discontinuance of this cooperative relation. The resources of the Yale Library we were enabled to supplement perfectly by xii A STUDY OF ANTHROPOID LIFE loans from the Library of Congress, Army Medical Library, Library of the Ameri- can Museum of Natural History, and the Library of Harvard University. Likewise the staff of the Yale University Press has acquainted us with a new standard of skill and efficiency in the conversion of manuscript into letterpress. Cooperation with the Press from first to last in the manufacture of this volume has been delightful. If there are errors or artistic defects in the book we suspect that the fault lies with the authors, not the publishers. At any rate, we have profound respect for the latter's acquaintance with their business, their mode of conducting it, and their uniformly courteous and constructive relations with authors. Except for the support of one or another aspect of our long-continued task of anthropoid research by the Carnegie Institution of Washington, the Rockefeller Foundation, the Laura Spelman Rockefeller Memorial, the Institute of Psychology, Yale University, and the sympathetic encouragement and assistance of our col- leagues, locally and throughout the scientific world, we certainly could not have gone forward steadily to the completion of our historical study and the presentation of this informational handbook. To all, our sincere and hearty thanks. New Haven, Connecticut March 23, igzg THE AUTHORS Preface List of Illustrations CONTENTS ix XV Part I. Historical 1. Ancient Knowledge of the Anthropoid Apes i 2. Knowledge of the Anthropoids through the Middle Ages to the End of the Seventeenth Century 8 Progress of Acquaintance with the Anthropoid Apes during the Eight- eenth Century i6 4. The Emergence of the Gorilla 27 5. Terms, Types, and Relations 36 Part 11. Gibbon 6. The Habits and Life History of Gibbon 47 5^ Affectivity and Its Expressions in Gibbon 63 8. Receptivity and Adaptivity in Gibbon 80 Part III. Orang-Oiitan 9. Structural Appearance, Species, Distribution, and Habitat of Orang- outan 103 10. Mode of Life of Orang-outan iii 11. Capture, Life in Captivity, and Diseases of Orang-outan 129 ^12). Social Relations and Life History of Orang-outan 136 13. Affective Behavior and Speech in Orang-outan 150 14. Nervous System and Receptivity of Orang-outan 166 15. Intelligence of Orang-outan: Perception, Endowment, and Acquisition 171 16. Intelligence of Orang-outan: Experimental Studies 181 Part IV. Chimpanzee 17. Structural Appearance, Species, Distribution, and Habitat of Chim- panzee i97 Manner of Life, Locomotion, Nesting, and Capture of Chim.panzee 209 T9. Habits of Eating and Drinking, Hygiene, and Care in Captivity of Chimpanzee 231 ^o) Social Relations of Chimpanzee 246 21. Life History of Chimpanzee 256 xiv A STUDY OF ANTHROPOID LIFE 22. Affective Behavior of Chimpanzee: Temperament and Expressivity 276 23. Affective Behavior of Chimpanzee: Behavioral Patterns of Emotion 288 24. Affective Behavior of Chimpanzee: Vocalization, Speech, Language, ^ and Intercommunication 301 ^^25. Nervous System and Receptivity of Chimpanzee 310 ._^6. Pejceptual Processes of Chimpanzee 324 2 7j^Inte]li<^ence of Chimpanzee: Opinions and Methods of Inquiry 336 28. Infelligence of Chimpanzee: Modes and Conditions of Behavioral Adaptation 344 29. Intelligence of Chimpanzee: Adaptation of Environment versus Self- adaptation 351 30. Intelligence of Chimpanzee: Imaginal Processes 365 Part V. Gorilla 31. Structural Appearance, Races, Distribution, and Habitat of Gorilla 381 32. Mode of Life, Locomotion, and Handedness of Gorilla 401 33. Nesting and Feeding Activities in Gorilla 412 ^ Hygiene, Health, and Care in Captivity of Gorilla 420 (35/ Social Relations of Gorilla 430 36. Life History of Gorilla 442 37. Affective Behavior of Gorilla: Temperament and Varieties of Expres- sion 455 38. Affective Behavior in Gorilla: Varieties of Emotional Pattern, and Motivation 467 39. Nervous System and Receptivity of Gorilla 476 40. Observational Ability and Perceptual Processes in Gorilla 486 41. Opinions Concerning Intelligence of Gorilla 492 42. Methods of Studying Behavioral Adaptivity in Gorilla 501 43. Concerning Memory, Insight, and Foresight in Gorilla 513 Part VI. Comparisons and Conclusions 44. Comparison of Anthropoid Types 529 /4V Comparison of Primate Types 562 46. Anthropoid Research in Retrospect and Prospect 581 Bibliography for Natural History and Psychobiology of the Anthropoid Apes to 1928 593 Subject and Author Index 619 ILLUSTRATIONS Part I. Historical 1. Animals, including a manlike creature, from Briedenbach's Travels, i486. Pier- pont Morgan Library 3 2. Representation of capture of apes in the act of putting on boots. From Piga- fetta, Latin edition, 1598. Drawn by De- Bry brothers 5 3. A figure from Gesner, 1602, who pre- sumably borrowed it from Brieden- bach 9 4. "Orang-outang," known to have been a chimpanzee. From Tulp, 1641 11 5. Creature called "Ourang Outang," evi- dently a pilose woman. From Bontius, 1658 12 6. "Orang-outang or Pygmie," actually a chimpanzee. From Tyson, 1699 14 7. "Singe" from Java, presumably in- tended to represent the orang-outan. From Leguat, 1708 17 8. "The Oran-ootan" of Borneo. From Beeckman, 1718 17 9. "Female Pygmy or Chimpanzee." From Boreman, 1739 18 10. The London chimpanzee of 1738. From Scotin, 1739 18 11. Chimpanzee, orang-outan, or both? From Edwards, 1758-64 19 12. Historically interesting figures bor- rowed from other authors by Hoppius, 1760 20 13. Male and female gibbons. From de Visme, 1769 21 14. "The Great Gibbon." From Buffon, 1766 21 15. The "Jocko" or chimpanzee. From Buffon, 1766 22 16. Orang-outans. From colored plate of Vosmaer, 1778 23 17. "Long-armed Ape," doubtless a gibbon. From Pennant, 1793 26 18. The chimpanzee, misnamed "Pongo" by the author. From Audebert, 1800 27 19. The orang-outan (immature), by the author misnamed "Jocko." From Aude- bert, 1800 27 20. The gibbon, "Simia lar/' From Aude- bert, 1800 28 21. The "Moloch," perhaps the gray gib- bon or wau-wau, Hylobates leuciscus. From Audebert, 1800 28 22. Drawing of a gibbon. From Harlan, 1825 30 23. Drawing of a young gorilla. From I. Geoffroy-Saint-Hilaire, 1851 33 24. Adult gorilla and young. From Gervais, 1854 33 25. Drawing of orang-outan heads. From Hermes, 1876 38 26. Drawing of orang-outan heads. From Hermes, 1876 38 27. White-cheeked gibbon, Hylobates leu- cogenys. From Sclater, 1877a 42 28. Hypothetical relationships of the pri- mates. From G. Elliot Smith, 1924 44 Part II. Gibbon 29. Siamang, with laryngeal sac inflated 50 30. Siamang, with laryngeal sac partially inflated 50 31. Female siamang, about five years old 51 32. Adult female wau-wau, H. leuciscus 52 33. The same wau-wau as that in fig. 32 54 34. White-handed gibbon, H. lar , 56 35. A baby gibbon in Siam, species unde- termined, said to be less than a year old 60 36. Portrait of a gibbon. Unidentified, but probably H. hoolock 65 xvi A STUDY OF ANTHROPOID LIFE 37. A gibbon expresses interest and sur- prise 67 38. Expression of fear in a gibbon 68 39. Friendliness expressed by a gibbon 70 40. Pepee, the white-cheeked gibbon studied by Boutan 89 41. Boutan experiment boxes. Redrawn from Boutan, 19 14 92 Part III. Orang-Outan 42. Changes in the facial outline and cra- nium of the orang-outan from infancy to maturity 105 43. Drawing of the mature male orang- outan, Max, captive in Paris, with laryn- geal sac inflated. From Delisle, 1895 106 44. Orang-outan youth. Julius, the five- year-old male studied by Yerkes, 191 6 108 45. Orang-outan maturity. An adult male 108 46. A young female orang-outan resting in tree 113 47. Characteristic postures and attitudes of young orang-outan and mature gibbon 114 48. Erect attitude of orang-outan, showing characteristic position of feet and arms 116 49. Erect attitude of orang-outan. A female about six years old 116 50. Young orang-outans at play 118 51. Infant female orang-outan, said to be about six months old 131 52. Youthful female orang-outan, about four years old 132 53. Mature male orang-outan. Max, drawn from life while captive in Paris. From Delisle, 1895 133 54. Old male orang-outan, Maurice, with immense cheek pads and fold of skin at throat. Drawn from life while captive in Paris. From Delisle, 1895 133 55. Orang-outan mother, Maggie, and in- fant son seven weeks old 137 56. Maggie and her month-old son in char- acteristic positions and relation 142 57. Maggie and son. Maternal restraint 143 58. Maggie and son 143 59. "Chief Utan," father of the infant shown in figures 55-58 145 60. Portrait of "Chief Utan" to show tex- ture of skin, beard, and size of cheek pads 146 61. Companionship as illustrated by young orang-outans 1 50 62. The mature male orang-outan, Cache- sita, aged about ten years, described by Yerkes, 1925 152 63. Interest. Youthful female orang-outan and proboscis monkey 153 64. Admonition. Orang-outan and probos- cis monkey 156 65. Discipline. Orang-outan and proboscis monkey, both in their childhood 158 66. Julius, a male orang-outan about five years old, who was subject in the experi- ments of Yerkes. Photographed beside the laboratory of G. V. Hamilton at Santa Barbara, California 183 67. Yerkes' multiple-choice apparatus, as used in study of orang-outan 184 68. Error curves in a multiple-choice ex- periment, for the orang-outan, Julius, and the monkeys, Sobke and Skirrl 186 Part IV. I 69. Adult male chimpanzee of the species Pan schweinjurthii 198 70. Adult female chimpanzee of the species Pan schweinjurthii 198 71. Immature female chimpanzee. Pan schweinjurthii 200 mpanzee 72. Female chimpanzee. Pan chimpanse, mature, estimated age twelve years 200 73. A vigorous mature but youthful male chimpanzee, with thick silvery coat 201 74. Male chimpanzee, Pan chimpanse, esti- mated age ten years 203 ILLUSTRATIONS xvii 75. Characteristic postures and attitudes of adult and young chimpanzee 211 76. Young male chimpanzee climbing a birch tree. Scene Yerkes farm, Franklin, New Hampshire 213 77. Adolescent female chimpanzee in birch tree at Franklin, New Hampshire 213 78. Childhood. A five-year-old male chim- panzee playing in a New Hampshire pas- ture 214 79. A pair of youthful chimpanzees climb- ing and swinging in the birches 214 80. Sleeping postures of the captive chim- panzee. Drawn from life by David N. Yerkes 226 81. Sleeping postures of chimpanzees. These individuals probably range in age from five to seven years. Drawn from life by David N. Yerkes 227 82. A group of chimpanzees from the Yale Primate Laboratory at dinner 233 83. Dinner time! Chimpanzees from the Yale Primate Laboratory 233 84. Young chimpanzee drinking milk from a bottle 234 85-88. Response of a young male chimpan- zee to mirror image of itself. Courtesy of N. Kohts, who generously permits us to reproduce these unpublished photographs of her subject "loni" 252 89. Infancy. A young male chimpanzee (P. schweinjurthii) 258 90. Childhood. A male chimpanzee (P. chimpanse) five or six years old 258 91. Maturity. An adult male chimpanzee (P. schweinjurthii) 259 92. Aged female chimpanzee. Said to be sixty years old 259 93. Maternity. The female chimpanzee Cucusa, with her infant son Anuma. This photograph was made for Mrs. Abreu shortly after the birth of Anuma in Ha- vana, 191 5 263 94. Infancy. A male chimpanzee, one day after birth. He was born in Philadelphia, October i, 1928 264 95. Bottle fed! The Philadelphia infant was reared thus 265 96. The Philadelphia chimpanzee of fig. 94, photographed when six weeks old 267 97. The Philadelphia infant when seven weeks old 268 98. Emotional expressions of the young chimpanzee 2 80 99. "Napoleon," a young male chimpanzee in Philadelphia, expresses anger 292 100. Mrs. Kohts's subject "loni" objects to experiments 294 101. Greetings! A young chimpanzee ex- presses interest and excitement 295 102. Mrs. Kohts experimenting with the chimpanzee "loni" 317 103. "loni" matching sample object in the experimenter's hand 320 104. Completion of response whose begin- ning is recorded in fig. 103 321 105. "loni" at work in Mrs. Kohts's labora- tory in Moscow 332 106. Perception of form 333 107. Perception of form. An error in match- ing sample 333 108. Food-containing box fastened by a padlock 352 109. A chimpanzee in the act of using key to open lock 352 1 10. A chimpanzee using boxes and stick as instruments 354 111. The chimpanzee "Sultan" constructing a serviceable instrument by joining two sticks 357 112. A group of chimpanzees working to- gether 359 113. Food-containing box fastened by a harness-snap 361 114. Success in opening the box 361 115. A hooked-rope problem. The chimpan- zee is in the act of removing ring from hook to obtain food-box 370 116. Successful solution of the hooked-rope problem. The chimpanzee is pulling the food-box within reach 370 117. Chimpanzee using a pyramid of boxes which it constructed in order to reach suspended bananas 373 118. Boxes arranged as a "four-story struc- ture" by a chimpanzee to obtain sus- pended food 374 xviii A STUDY OF ANTHROPOID LIFE Part V . Gorilla 119. A drawing of the Wombwell gorilla 383 120. "John Daniel," the Cunningham speci- men of G. gorilla mounted 384 121. The Cunningham gorilla "Sultan" or "John Daniel II." A young male G. go- rilla 385 122. A group of mountain gorillas mounted by Carl Akeley 388 123. Mounted adult specimen of Gorilla go- rilla 392 124. Mounted specimen of mountain gorilla 393 125. Gorilla or chimpanzee? A young male chimpanzee which was mistaken for a go- rilla 394 126. The male chimpanzee "Chim," ob- served by Yerkes. He resembled the go- rilla more closely than do most examples of his genus 394 127. The habitat of the mountain gorilla, showing a natural shelter 396 128. A recently vacated night shelter of a family of mountain gorillas 398 129. An adult mountain gorilla, G. beringei, mounted by Carl Akeley 404 130. Profile of a full-grown male mountain gorilla, mounted by Carl Akeley 407 131. The bed or nest of a mountain gorilla in the crotch of a tree on Mt. Karisimbi, at an altitude of about 11,000 feet 413 132. Sultan, aged about five years, drinking from a cup 419 133. Portrait of female G. gorilla, aged ap- proximately three years 42 2 134. Profile of young female G. gorilla 422 135. Seriousness of expression in young fe- male G. gorilla. The look of distress is not a favorable sign 432 136. Another view of a child gorilla 432 137. Sultan (Cunningham gorilla) at play in the London Zoological Garden 436 138. Congo seeking contact with her mirror image 438 139. The young female mountain gorilla Congo kissing her mirror image 438 140. An infant gorilla (G. gorilla) , aged one month, with foster nurse in Africa 443 141. The Reichenow gorilla, aged two months 445 142. The Reichenow gorilla, aged five months 445 143. Another view of the Reichenow go- rilla, aged five months 447 144. The Reichenow gorilla (right), aged seven months, with an infant chimpanzee 447 145. The Reichenow gorilla, aged seven and one-half months, walking 449 146. The Reichenow gorilla, aged seven and one-half months, running 449 147. The infant gorilla Bamboo, playing with a ball in the Philadelphia Zoological Garden 450 148. Portrait of infant male G. gorilla Bam- boo, estimated age two years 452 149. The adolescent mountain gorilla Congo. Postures such as this are often taken by gorillas 457 150. Congo at attention 460 151. Congo beating her chest 463 152. Motion picture of the mountain gorilla Congo beating her chest with her hands, while holding a milk bottle with her feet 465 153. Site of Yerkes' experiments with Congo, estate of James Burbridge, Jack- sonville, Florida 502 154. Congo using a stick as instrument 507 155. Congo trying to reach an apple with a stick 507 156. Congo working at the box and pole problem 509 157. The use of boxes as instruments. Congo at work 511 158. A three-box pyramid constructed by Congo to reach suspended food 511 159. Congo in a memory experiment. The letters w, g, b, r, designate boxes any one of which may contain food 516 160. Congo, moored to stake in memory ex- periment, waiting impatiently 518 161. Turntable apparatus for study of de- layed response 519 162. Turntable apparatus and grill through which animal reaches to operate mecha- nism 519 163. Motion picture of Congo operating the turntable in a memory experiment 520 ILLUSTRATIONS xix Part VI. Comparisons 164. Infant gorilla, Bamboo (left) and chimpanzee, Lizzie. Probably neither is far from two years old 531 i 165. Gorilla, Bamboo (above), and orang- outan. Orphan Annie. Estimated ages two i years and one year respectively 533 166. View of the Abreu Primate Colony at i Havana, Cuba 583 167. Cages for anthropoid apes on the Abreu estate in Havana 584 i 168. General view of the station and labo- and Conclusions ratories of the Pasteur Institute at Kin- dia, Africa 585 69. The setting of the Pasteur Institute Station at Kindia 585 70. Interior of primate quarters, Pasteur Institute Station, Kindia 586 71. Building and outdoor cages of Primate Laboratory, at Yale University, New Ha- ven, Connecticut 587 72. Yale Primate Laboratory at New Ha- ven, Connecticut 587 PART I. HISTORICAL CHAPTER ONE ANCIENT KNOWLEDGE OF THE ANTHROPOID APES WHAT fascination of retrospect and revery if, to thousands of generations, one could marshal his ancestors for familiar salutation and inspection. A hundred generations pass, and one views with popping eyes forbears of Aristotelian times; another hundred, and with bated breath one gazes on folk who have left scant record in artifact or rock; barely another hundred, and one's historical orientation fails. A thousand pairs pass, and the sense of understanding, sympathy, and kinship has markedly di- minished. Would the procession sooner or later bring each of us face to face with a direct ancestor so apelike that he might be mistaken for, or identified with, the chim- panzee, gorilla, or orang-outan? Study of the form, activities, and crea- tions of existing anthropoid apes may not answer the question, but combined with paleontological research, into human, pre- human, anthropoid, and pre-anthropoid ex- istence, it should enable us partially to trace our descent and to construct our family tree. Students of psychobiology are in the midst of diligent and exciting search for anthropoid information. The opportune moment to attempt the coordination and interpretation of diverse assemblages of facts has not arrived. Consequently it is our immediate task, as writers of this book, to inquire particularly and minutely, aided by historical documents and our own powers of observation, into the life history and action-system of the anthropoids. We shall endeavor to picture clearly in psycho- biological terms the active life of those in- frahuman primates which structurally, as well as psychologically and socially, re- semble us most closely. We shall not write imaginative genetic history, nor shall we theorize or generalize from fragmentary knowledge. It is significant in connection with our task that for thousands of years, and prob- ably tens of thousands, anthropoid apes have shared the earth with man without 2 A STUDY OF ANTHROPOID LIFE the development of mutually agreeable and helpful social relations. No infrahuman pri- mate, least of all the great ape, has been thoroughly domesticated. Neither has man come into intimate sympathetic touch with the lives of these creatures, except as they or he were held in captivity. Slave makers though we be, the other primates have es- caped servitude. As captives they seldom play other roles than those of pet and en- tertainer. Although we cannot with accuracy por- tray the procession of our ancestors, we may with fair assurance mark the dawn and trace the growth of our knowledge of the anthropoid apes. Such a historical sur- vey, brief and orientational, may serve as introduction to this systematic account of anthropoid behavior. In the ancient cultures of Europe, Asia, and Africa are preserved records of certain infrahuman primates. Whether anthropoid or not it often is impossible to decide. Names, incidents, adventures, items of nat- ural history, pictorial and verbal descrip- tions, supposedly referring to apes, mon- keys, baboons, or other primates, are our legacy. Precious though these fragments must seem to the erudite historian and the specialist in human origins, they are pe- culiarly unsatisfactory to us because it is seldom possible to identify the type of ani- mal in question. Names there are, but with- out exhibits attached; descriptions abound, but they are too meager or inexact to lead to certain identification. What at first im- presses one as valuable information turns out finally to be scarcely more than the ap- pearance of fact. That several kinds of infrahuman pri- mate have been known for upward of three thousand years at least is well attested by historical evidences; but that any of the four existing types of anthropoid ape — gib- bon, orang-outan, gorilla, chimpanzee — were among them is extremely doubtful. By presenting a few examples of these an- cient descriptive references we shall hope to exhibit their quality and value, while thereby suggesting explanation for the brevity of our discussion of the subject. In this work, devoted as it is to a statement of what is definitely known about anthro- poid behavior, it seems more fitting to sketch the history of the growth of knowl- edge than to describe it fully and in detail; to refer the reader to the most satisfactory historical summaries and the most valuable sources instead of reproducing, perhaps for the hundredth time, what is easily avail- able to anyone who cares to command the resources of our great libraries. As we have examined the abundant but widely scattered literature of our subject, we have been deeply and unfavorably im- pressed by the uncritical copying, quoting, or paraphrasing of author by author. Su- perstitions, surmises, rumors, accidental and unverifiable observations, inferences, and unwarranted conclusions, have been repeated through the centuries. As one con- templates the utter wastefulness and the negative intellectual value of this proce- dure one is depressed and comes to feel that a worth-while task is better once well done than a hundred times imperfectly. The hundreds of descriptions, discussions, and re-discussions of anthropoid life and behavior which we have examined make us feel that it is a pity man should write so much, while observing, reflecting, and criti- cizing himself and his work so little. But we must enter upon our adventure in the realm of relative ignorance. Some centuries before the present era it was writ- ten: For the king's ships went to Tarshish with the servants of Huram : every three years once came the ships of Tarshish bringing gold, and silver, ivory, and apes, and peacocks. (Holy Bible, II Chron. 9. 21.) Apes, yes, but what ape is meant? May we infer that certain African types were referred to, and, if so, were they anthropoid apes, monkeys, or baboons? Who can tell? In the fifth century, B.C., one Hanno, a Carthaginian admiral, is supposed to have made a voyage of exploration and coloniza- tion along the west coast of Africa. His description, as it appears in the translated ANCIENT KNOWLEDGE OF THE ANTHROPOID APES 3 Periplus, contains the following notable passage: On the third day after our departure thence, having sailed by those streams of fire, we arrived at a bay called the Southern Horn; at the bot- tom of which lay an island like the former, hav- ing a lake, and in this lake another island, full of savage people, the greater part of whom were women, whose bodies were hairy, and whom our interpreters called Gorillae. Though we pursued the men, we could not seize any of them; but all fled from us, escaping over the precipices, and defending themselves with stones. Three women were however taken; but they attacked their conductors with their teeth and hands, and could not be prevailed on to accompany us. Having killed them, we flayed them, and brought their skins with us to Carthage. We did not sail fur- ther on, our provisions failing us. (Hanno, Peri- plus, translated from the Greek by Falconer, i797, pp. 13-15) Is this the first record of the gorilla, to- day so called, or is the reference to some other creature? Authorities differ: some say human pygmies or dwarfs; some, chimpan- zees; some, an extinct race of -African apes; and some, gorillas. To us the presumption seems slightly in favor of the chimpanzee or an extinct type of anthropoid. We, therefore, are unwilling to date the dis- covery of that largest of manlike apes, the gorilla, from the time of Hanno. Shortly after the adventure of Hanno, and in the fourth century, B.C., Aristotle, industrious gatherer of naturalistic infor- mation, offered in his famous history of animals a description of the ape which marks the beginning of our historical ad- venture. Some animals share the properties of man and the quadrupeds, as the ape, the monkey, and the baboon. The monkey is a tailed ape. The baboon resembles the ape in form, only that it is bigger and stronger, more like a dog in face, and is more savage in its habits, and its teeth are more dog-like and more powerful. Apes are hairy on the back in keeping with their quadrupedal nature, and hairy on the belly in keeping with their human form— for, as was said above, this characteristic is reversed in man and the quadruped— only that the hair is coarse, so that the ape is thickly coated both on the belly and on the back. Its face resembles that of man in many respects; in other words, it has similar nostrils and ears, and teeth like those of man, Fig. I. Animals, including a manlike creature, from Brie- denbach's Travels, i486. Pierpont Morgan Library. both front teeth and molars. Further, whereas quadrupeds in general are not furnished with lashes on one of the two eyeHds, this creature has them on both, only very thinly set, especially the under ones; in fact they are very insignificant in- deed. And we must bear in mind that all other quadrupeds have no under eyelash at all. The ape has also in its chest two teats upon poorly developed breasts. It has also arms hke man, only covered with hair, and it bends these legs like man, with the convexities of both limbs facing one another. In addition, it has hands and fingers and nails like man, only that all these parts are somewhat more beast-like in appear- ance. Its feet are exceptional in kind. That is, they are Hke large hands, and the toes are like fingers, with the middle one the longest of all, and the under part of the foot is Hke a hand except for its length, and stretches out towards the extremi- ties like the palm of the hand; and this palm at the after end is unusually hard, and in a clumsy obscure kind of way resembles a heel. The crea- ture uses its feet either as hands or feet, and doubles them up as one doubles a fist. Its upper- arm and thigh are short in proportion to the fore- arm and the shin. It has no projecting navel, but only a hardness in the ordinary locality of the navel. Its upper part is much larger than its lower part, as is the case with quadrupeds; in fact, the proportion of the former to the latter is about as five to three. Owing to this circumstance and to 4 A STUDY OF ANTHROPOID LIFE the fact that its feet resemble hands and are com- posed in a manner of hand and of foot : of foot in the heel extremity, of the hand in all else — for even the toes have what is called a "palm": — for these reasons the animal is oftener to be found on all fours than upright. It has neither hips, inas- much as it is a quadruped, nor yet a tail, inas- much as it is a biped, except by the way that it has a tail as small as small can be, just a sort of indication of a tail. The genitals of the female re- semble those of the female in the human species; those of the male are more like those of a dog than are those of a man. (Aristotle, Historia Ani- malium, translated by Thompson, 1910, Bk. II, 8.) Assured of the trustworthiness of Aris- totle, we may conclude from his description that the ancients, possibly of twenty-five hundred years ago, were familiar with four groups of primate: man, tailless apes, tailed monkeys, and baboons. Which, if any, of the anthropoid apes were known, remains unanswered. Aristotle's descrip- tion might well have been based on the magot of Cuvier, now the Barbary ape, a tailless form once grouped with the apes, as contrasted with the monkeys, but not an anthropoid ape. That Aristotle's sources ac- quainted him with the existence and nature of gibbons or of any one of the three man- like apes is highly improbable. Neverthe- less, his statements are peculiarly impor- tant to us as marking a step toward the taxonomic adequacy of description. We are not convinced, however, that his historical sources, or his personal observation, sup- plied data for reliable description of any one of the anthropoid apes. Early in the Christian Era, and some four centuries after Aristotle, Pliny the Elder repeated the task of gathering into a single work current knowledge of the pri- mates. Unlike Aristotle, he included also sealing wax and kings! Undoubtedly Pliny drew abundantly from Aristotle and Juba, but naturally he commanded also varied and more recent sources of information. His remarkable history of the world makes interesting reading, if one gives his sense of humor rein and is not too squeamish about matters of fact and fitness. Truly the work is an odd mingling of fact and fancy. Among the Westerne mountaines of India the Satyres haunt, (the countrey wherein they are, is called the region of the Cartaduli) creatures of all other most swift in footmanship : which one whiles run with all foure; otherwhiles upon two feet onely like men : but so light-footed they are, that unlesse they be very old or sicke, they can never bee taken. Tauron writeth, That the Choro- mandae are a savage and wild people : distinct voice and speech they have none, but in steed thereof, they keepe an horrible gnashing and hide- ous noise : rough they are and hairie all over their bodies, eies they have red Uke the houlets, and toothed they be like dogs. Eudoxus saith, That in the Southerne parts of India, the men kind have feet a cubite long, but the women so short & small, that thereupon they be called Struthopodes, i. sparrow footed. Megasthenes is mine author, that among the Indian Nomades there is a kind of people, that in steed of noses have only two small holes, and after the manner of snakes have their legs and feet limmer, where- with they crawle and creepe, and named they are Syrictae. (Plinius, Natural History, translated by P. Holland, 1601, p. 156.) Those interpreters of this passage who are eager to discover anthropoid apes in ancient writings identify "Satyres" as gib- bons, "Choromandae" as baboons, and "Syrictae" as orang-outans. Possibly they are right, but to follow them certainly re- quires a robust will to believe. In the following passage we note varie- ties of observation which are reported throughout the centuries with surprisingly little variation or supplementation. Verily, the pathway to exact knowledge, even of such impressive objects as apes, seemeth difficult. All the kind of these Apes approach neerest of all beasts, to the resemblance of a mans shape : but they differ one from another in the taile. Marvellous craftie and subtle they be to beguile themselves : for by report, as they see hunters doe before them, they will imitate them in every point, even to besmeare themselves with glew and birdlime, and shoo their feet within grins and snares, and by that meanes are caught. Mutianus saith, that he hath seene Apes play at chesse and tables; and that at first sight they could know nuts made of waxe from others. (Plinius, op. cit., p. 231.) Whereas in pre-Christian writings the descriptions seem oftenest to apply to Afri- can primates, in Pliny, and for some cen- ANCIENT KNOWLEDGE OF THE ANTHROPOID APES 5 turies after him, Asiatic forms are more frequently mentioned. One can scarcely be- lieve that in the time of Pliny any of the types of anthropoid ape were entirely un- Fig. 2. Representation of cajiture of apes in the act of putting on boots. From Pigafetta, Latin edition, 1598. Drawn by DeBry brothers. known. Indeed, the evidences convince us that gibbons, orang-outans, chimpanzees, and possibly also gorillas, had been heard of by many cultured persons through the reports of collectors, travelers, and ex- plorers. Possibly some persons with inter- est in medicine or natural history had seen specimens. But in any event they were so meagerly and inaccurately known as to render identificational descriptions impos- sible. Confusion of types of infrahuman primate among themselves, and of them with mythical or imperfectly known human groups, was prevalent and continued so for several centuries. After the work of Pliny the Elder, yet another century elapsed and that great pio- neer in medical science and art, Galen (130-200? A.D.), began to search the world for anatomical materials. Although his works do not, so far as we have been able to learn, make specific reference to the types of primate dissected and described, the anatomists Tyson and Camper infer from his writings that he was familiar with certain monkeys, baboons, the orang-outan, and possibly also the gibbon. The latter, however, Camper questions. Tyson, who in 1699 described the chim- panzee under the name "orang-outang," re- marks: Galen formerly dissected Apes and Monkeys, and recommended to his Scholars the frequent Anatomizing them, as useful for the attaining the Knowledge of the Structure of the Parts in Hu- mane Bodies. Had he met with our Animal, it had served his turn much better: Nor had he been liable to some Mistakes, which Vesalius charges him with, since in so many Parts, the Orang-Outang imitates a Man, more than Apes and Monkeys do. (Tyson, 1699, preface.)^ In illuminating comment on grounds of confusion of anthropoid types by the an- cients, Tyson continues: This great Agreement, which I observed be- tween the Orang-Outang, and a Man, put me upon considering, whether it might not afford the Occasion to the Ancients, of inventing the many Relations, which they have given us of several sorts of Men, which are no where to be met with but in their Writings. For I could not but think, there might be some Real Foundation for their Mythology ; which made me more strictly enquire into their Records; and examining them, I always found something new, that insensibly lead me on far beyond what at first I intended: and if I do not deceive my self, I have at last gained a clearer Light in these Matters, than any that has hitherto appeared. For what created the greatest difficulty, was their calling them Men, but yet with an Epithet for distinction sake; as the . . . Wild Men, the Little Men, the Pygmcean Men, the Black Men, the Men with Dogs Faces, &c. yet at the same time I find that they made them . . . Wild Beasts; and if so, no doubt but they were of the Quadru-manus kind; i.e. either Apes or Monkeys. And such were likewise the Satyrs, the Fauni, Pan, ^gipan, Sylvanus, Silenus, and the Nym- phoe, as also the Sphinges of the Ancients. But so many Romances have been made about them, that not only Strabo formerly, but the most noted Men of Learning of late, have looked upon them as meer Fictions of the Poets, and have utterly denied them any real Being. Homer's Geranomachia therefore, or Fight of the Cranes and Pygmies, I have rendered a probable Story. Aristotle's assertion of the being of Pygmies, I have vindicated from the false Glosses of others. The Conjectures of other Learned Men about 1 Reference is by date of publication to general bibhography at end of volume. 6 A STUDY OF ANTHROPOID LIFE them, I have examined: And by what I have said in the following Philalogical Essay, I think I have fully proved, that there were such Animals as the Ancients called Pygmies, 'Cynocephali, Satyrs, and Sphinges; and that they were only Apes and Monkeys. (Preface.) Throughout this passage orang-outan must be translated chimpanzee, since it is certain from Tyson's description of source and anatomical characters that he refers to the smaller of the African anthropoid apes. Galen noted the greater anatomical simi- larity between ape and man than between baboon and man. An Ape is the most like a Man of any Quad- ruped: In the Viscera and the Muscles, and in the Arteries, and Veins and Nerves, because 'tis so in the structure of the Bones. For 'tis from their make, that it walks on two Legs, and uses its fore-limbs as Hands. It hath the largest Breast of any Quadruped, and Clavicles or Collarbones like a Man, and a round Face, and a small or short Neck. (Galenus, D'Anat. Administr. lib. i, cap. 2, p.m. 26. Our quotation is from Tyson, 1699, p. 15.) Writing in 1779, Camper, a pioneer in comparative anatomy, remarks: Being Professor of Natural Philosophy, Anat- omy, Surgery, and Physic, in the University of Franeker in Friesland, I soon perceived the im- possibility of understanding the most precious and valuable works of the immortal Galen (especially his anatomical works) without dissecting monkies, to compare his exact descriptions with. I got for that purpose, in the year 1754, a Cynocephalus, and was charmed to find the exactness of almost all Galen's descriptions. The organ of speech puz- zled me, nevertheless, very much, and I was not able to explain his observations, so as to satisfy myself in this animal: I was obhged, therefore, for want of other apes, to delay my researches to another opportunity, which, however, I did not meet with till I came to Amsterdam, where I set- tled in the year 1755. . . . As Galen not only dissected the Cebi, or the Cynocephalus, who are all of the tailed or caudati kind, but the Pithecos or ape without a tail; and as the celebrated Dr. Tyson had found the organ of voice so similar to that of men in his Pigmy, I endeavoured to get one from the East Indies. For this purpose I offered a good sum of money to my correspondents to have a well-preserved Orang Outang, because none were to be met with in any collection of Natural History in Holland. (Camper, 1779a, pp. 140-141, 144.) Camper goes on to report success in ob- taining specimens of the Asiatic orang- outan and also of what he calls the Ango- lese Orang, which is known to us as the chimpanzee. His principal conclusion, as far as Galen's knowledge of the anthro- poids is in question, is thus stated: The organs of voice of the Angolese Orang, dissected by Tyson, are very different from those of the Pithecos which I dissected 1777. This one had the os hyoides like all the papiones or sphinges, &c.; the epiglottis perforated as in fig. 3 and 4 and therefore different from Galen's de- scription, and from Tyson's, who makes no men- tion at all of the one, nor of the two bags which Galen describes, and which I found in the real Orang of Borneo; not only in one specimen, but in five, which I have dissected for that purpose. To return to Galen; I am very apt to think that he dissected an Asiatic Orang, from which he took his description of the ventricles a latere lingulcB, at the sides of the epiglottis. (Camper, 1779a, p. I47-) The opinions of Tyson and Camper, based as they are on first-hand acquaint- ance with the structure of a manlike ape (either chimpanzee or orang-outan) and on intimate knowledge of the writings of Galen, certainly command serious con- sideration and confidence. We are impelled thereby to date definitely scientific ac- quaintance with an anthropoid ape from the time of Galen and to assume that he described exactly and in detail certain structures and anatomical characteristics of at least one type of existing anthropoid ape. Our exhibits and comment on ancient knowledge of the primates should acquaint the reader with its nature and especially its peculiar limitations. Much evidently was known uncertainly and imperfectly. But instead of a consistent descriptive fabric of verifiable information, our prede- cessors of the pre-Christian Era possessed fragments which they variously fitted to- gether according to current rumor, super- stition, and immediate purpose. Other and abler historians and inter- preters of evidence than we have given lavishly of their time and skill in the study ANCIENT KNOWLEDGE OF THE ANTHROPOID APES 7 of this subject. It, therefore, is both our good fortune and our pleasure to be able to refer the reader to their reasonably sys- tematic, complete, and detailed discussions. As together giving an excellent general ac- count of ancient knowledge of infrahuman primates we should recommend Gesner (1551), Aldrovandi (1637), Tyson (1699), Hoppius (1760), Camper (1779, complete works 1803), Lichtenstein (1791), de Blainville (1840), and Huxley (1863). Lichtenstein is the author of a scholarly philological essay in which he attempts to discover the nature and extent of the an- cients' knowledge of the primates, and to relate their names for the different types to the nomenclature of his own day and especially to that of Linnaeus. The best re- view of the entire subject which we have found in English is that of de Blainville, who, unlike most writers on the topic, was familiar with the important publication of Lichtenstein and several times refers to it. Huxley examines the subject with charac- teristic insight, feeling for values, and clarity. His essay "On the natural history of the man-like apes" continues to be an excellent introduction. CHAPTER TWO KNOWLEDGE OF THE ANTHROPOIDS THROUGH THE MIDDLE AGES TO THE END OF THE SEVENTEENTH CENTURY FROM the second century to the sixteenth, acquaintance with the primates seems chiefly to have per- ished with its possessors. Few written docu- ments or other easily interpretable evi- dences are available to us, and in such as we have we find no additional information about the anthropoid apes. Marco Polo, in the thirteenth century, mentioned Asiatic creatures which may have been anthropoids. It should be known that what is reported re- specting the dried bodies of diminutive human creatures or pigmies, brought from India, is an idle tale, such pretended men being manufactured in this island in the following manner. The coun- try produces a species of monkey, of a tolerable size, and having a countenance resembhng that of a man. Those persons who make it their business to catch them, shave off the hair, leaving it only about the chin and those other parts where it naturally grows on the human body. They then dry and preserve them with camphor and other drugs, and having prepared them in such a mode that they have exactly the appearance of little men, they put them into wooden boxes, and sell them to trading people, who carry them to all parts of the world. But this is merely an imposi- tion, the practice being such as we have described ; and neither in India, nor in any other country, however wild (and little known) have pigmies been found of a form so diminutive as these ex- hibit. {The Travels of Marco Polo. Translated by Marsden, 1818, p. 604.) Possibly the "monkeys" thus used com- mercially were gibbons. In his description of Kumari, a province in the extreme southern promontory of India, the same author writes: The country is not much cultivated being chiefly covered with forests, which are the abode of a variety of beasts, especially apes, so formed and of such a size as to have the appearance of men. There are also long-tailed monkies, very dif- ferent from the former in respect to magnitude. {Op. cit., p. 683.) The historical value of Marco Polo's references to primates is slight; their sci- entific value, negligible. They have been mentioned here as harbingers of the dawn or revival of scientific interest in our sub- ject. During the sixteenth century Konrad Gesner, impatient of scholasticism, imbued with the spirit of inquiry, and learned in the biology of his time, assembled in a truly remarkable compilation all available information about the Simla. Drawing in- telligently and freely from the writings of such historical beacons among the ancients as Aristotle, Albertus Magnus, Pliny, and Galen, Gesner (1551) describes the variety, distribution, habitat, appearance, mode of life, and mental traits of the known pri- mates. For the modern student Gesner's record is of the utmost interest, since it is an admirable account of the knowledge of the ancients, a vivid picture of the credu- lity, superstition, and fancifulness of the Middle Ages, and a determined effort to distinguish the true from the false. His representation of an anthropoid ape, repro- duced as figure 3, gives one a startling im- pression of the inaccuracy and inadequacy of anthropoid knowledge at that time. (Ges- ner, Historiae Animalium. Edition of 1602, I, 847-871.) Although historically the work of Ges- ner seems to us of very high value, it con- tributes almost nothing to our knowledge of the types of anthropoid ape and their Hfe. Belonging in the period with Gesner, and writing almost simultaneously, is Filippo Pigafetta (1591) who in his description of the African Congo reports the observations of a Portuguese sailor, Duarte Lopez. Hartmann (1885) states that this author KNOWLEDGE THROUGH THE SEVENTEENTH CENTURY 9 describes the chimpanzee, but we have failed to discover in Pigafetta justification of the inference. Of "munkies" and "babownes" one Richard Jobson, shortly after the time of Pigafetta, wrote entertainingly and even correctly, except for confusion of types. For whereas the introductory portion of the account of the "babowne" conforms to our knowledge of that primate, the latter part seems rather to apply to the chimpan- zee. In support of this opinion we quote a few sentences: But to speake of the Babowne, I must say, it is a wonderfull thing, to observe a kind of com- mon wealth that is amongst them; they have none but their owne kind together, and are in heardes, of three or f oure thousand in a company ; as they travell, they goe in rancke, whereof the leaders are certaine of the greater sort, and there is as great, and large of them, as a Lyon, the smaller following, and ever now and then as a Commaunder a great one walkes; the females carry their yong under their bellies, except shee have two, and then one under, the other above. In the rear comes up a great company of the big- gest sort, as a guard, against any persuing enemy, and in this manner doe they march along: they are very bold, and as we passe in the river, when we come neare their troupes, they will get up into the trees, and stand in gaze upon us, and in a kind of collericke humour the great ones will shake the trees, and with his hands clatter the boughes in that fashion, as it doth exceed the strength of a man, to doe the like, barking, and making a noyse at us, as if they were much offended, and in this manner, many times they will follow us along, and in the night time, where wee ride at an ancker take up their stands, or lodgings on the moun- taine toppes, or on the trees that are above us, whereas we heare their government : for many times in the night you shall heare such a noyse of many of their voyces together, when instantly one great voyce exalts it selfe, and presently all are hush, and the noyse is dasht, so as we were wont to say, Maister Constable speakes; likewise when wee are a shore and meete with these troupes, on a sudden the great ones will come forward, and seeme to grin in our faces ; but offer up a gunne, and away they packe. (Jobson, The Golden Trade, 1623. Quotation from new edition by Charles G. Kingsley, 1904, pp. 183-185.) And later: And lastly let mee tell you that wee have seene in the desert places they use, trees and plants, wound and made up together in that artificiall manner, and wrought together with that thicknes over head, to keepe away the sun, and shade the ground, which hath bin beaten, & smoothed under neath, and all things in the manner and shape of an excellent arbour, which place they have only used, and kept for their dancing and recreation; that no man living that should have come by chance, and seene the same, without knowledge of these unlucky things, but would have confi- dently supposed, it had, and must have beene the handy worke of man; which some wayes con- firmes the opinion the Spaniard holds of them, and doth not sticke to write it, that they are absolutely a race and kind of people, who in re- gard they will not bee brought to worke, and live under subjection, refuse to speake, and so he re- ports of them. {Op. cit., pp. 185-186.) Certain authorities, notably Hartmann (1885, p. 4), date definite knowledge of the gorilla from the report of Battell, who, Fig. 3. A figure from Gesner, 1602, vol. i, who presum- ably borrowed it from Briedenbach. 10 A STUDY OF ANTHROPOID LIFE taken prisoner by the Portuguese in 1559, spent several years in Africa. The narrative of Battel! was published in 161 3 in Pur- chas his Pilgrimes, but the passage of particular interest in this connection is not found in editions prior to that of 1625. Be- cause of its unique historical significance we quote Battell's description of the Afri- can anthropoid apes, and also the editor's comment. The Woods are so couered with Baboones, Mon- kies, Apes, and Parrots, that it will feare any man to trauaile in them alone. Here are also two kinds of Monsters, which are common in these Woods, and very dangerous. The greatest of these two Monsters is called, Pongo, in their Language : and the lesser is called, Engeco. This Pongo- is in all proportion like a man, but that he is more like a Giant in stature, then a man : for he is very tall, and hath a mans face, hollow eyed, with long haire vpon his browes. His face and eares are without haire, and his hands also. His bodie is full of haire, but not very thicke, and it is of a dunnish colour. He differeth not from a man, but in his legs, for they haue no calfe. Hee goeth alwaies vpon his legs, and carrieth his hands clasped on the nape of his necke, when he goeth vpon the ground. They sleepe in the trees, and build shelters for the raine. They feed vpon Fruit that they find in the Woods, and vpon Nuts, for they eate no kind of flesh. They cannot speake, and haue no vnderstanding more then a beast. The People of the Countrie, when they trauaile in the Woods, make fires where they sleepe in the night ; and in the morning, when they are gone, the Pongoes will come and sit about the fire, till it goeth out : for they haue no vnderstanding to lay the wood together. They goe many together, and kill many Negroes that trauaile in the Woods. Many times they fall vpon the Elephants, which come to feed where they be, and so beate them with their clubbed fists, and pieces of wood, that they will runne roaring away from them. Those Pongoes are neuer taken aliue, because they are so strong, that ten men cannot hold one of them : but yet they take many of their young ones with poisoned Arrowes. The young Pongo hangeth on his mothers bellie, with his hands fast clasped about her: so that, when the Countrie people kill any of the femals, they take the young one, which hangeth fast vpon his mother. When they die among themselues, they couer the dead with great heapes of boughs and wood, which is commonly found in the Forrests. The editor, Purchas, comments as fol- lows: The Pongo, or Giant-ape. He told me in con- ference with him, that one of these Pongcs tooke a Negro Boy of his, which liued a moneth with them. For they hurt not those which they surprise at vnawares, except they look on them, which hee auoyded. He said, their highth was like a mans, but their bignesse twice as great. I saw the Negro Boy. Their strength. What the other Monster should be, he hath forgotten to relate: and these papers came to my hand since his death, which otherwise in my often conferences I might haue learned. Perhaps he meaneth the Pigmey Pongo- killers, mentioned. (Purchas, Hakluytus Posthu- mus, or Purchas his Pilgrimes, 4th ed., 1625, II, 981-982.) Was Battell acquainted with the gorilla? We think he was, for although it is pos- sible that Pongo refers to the adult chim- panzee and Engeco to the young of this ape, Battell's statements about the size and appearance of the Pongo more nearly fit the gorilla than the chimpanzee; and, furthermore, his failure to describe the "smaller monster," the Engeco, may indi- cate its relatively greater abundance and its less impressive character. It is our opin- ion that this adventurer either saw or learned from the natives of the existence of gorillas and chimpanzees. But even if we are correct in this surmise, we grant that knowledge of the African anthropoids was not advanced much by the Battell report. The Italian naturalist Ulisse Aldrovandi, in the latter half of the sixteenth century, undertook to assemble, in a magnum opus, the natural history of his times. A volume which he published in 1637 contains a notable chapter on Simla, in which, follow- ing Gesner and borrowing freely from him, the author considers historically and in the spirit of his times, nomenclature, types and classifications, structure, nature and habi- tat, foods and habits of life, sexual be- havior and reproduction, modes of capture, likes and dislikes, diseases, problems, prov- erbs, symbols, dreams, stories, graphic representations, and varied curious and in- teresting miscellany. So far as we know, this work has not been translated from the Latin. Like Gesner's great work, it is an eminently useful assembling and order- ing of information. Those with taste for the KNOWLEDGE THROUGH THE SEVENTEENTH CENTURY ii odd in history will find it fascinating, whereas the biologist who comes to it with- out historical background and appreciation of the characteristics of the medieval mind and its information will be dismayed by its seeming chaos and credulity. In no other single work, unless it be that of Gesner, can one find so many imaginative stories of the infrahuman primates and other curi- osities of natural history. Aldrovandi failed utterly if he tried to discriminate between the true and the false, for his book is not a whit more reliable than are those of certain earlier writers. The following brief quotation does full justice to the style, content, and evalua- tions of Aldrovandi's description. With difficulty we resist the temptation to offer more. According to Porta, the monkey leaps back on seeing a tortoise, even though bound. Erasmus, in a dialogue on friendship, tells how a boy on whose head was placed a tortoise shell, took a monkey in his arms, but the latter, about to hunt for lice in the boy's head, perceived the shell and jumped back with such horror that he nearly died. Hactenus tells of a monkey surrounded by a circle of snails and afraid to touch them. (Al- drovandi, De Qiiadrupedibus Digitalis Viviparis, 1637, p. 232.) An anthropoid ape called the Indian Satyr (Satyrus Indicus) in 1641 was de- scribed by Nicolaas Tulp wdth adequate detail and accuracy to permit its identifi- cation as a chimpanzee. The specimen was brought from Angola and presented to Frederic Henry, Prince of Orange. Following his general description of the appearance and behavior of this ape, Tulp continues : So nothing more Hke this one's imitation was represented by the Satyrs of old. Which Plinius (Bk. VII, chap. 3) describing to his readers, wrote expressly "there is an animal, a quadruped, in the tropical mountains of India, a most pernicious one; with a human figure, but with feet of a goat ; and with a body hairy all over. Having none of the human customs; rejoicing in the shadows of the wood; and fleeing from intercourse with men." From these characteristics the Satyr of the blessed Hieronymus differs somewhat perhaps : yet it agrees nevertheless, with the figures of the Poets. There was, he says: "a man with nostrils turned inward and a rough face with horns ; with the extremes of the body ending in feet of goats." Which same form the poets expressing most clearly, call their Satyrs lascivious, shameless, two-formed, two-horned, and with the wanton inclinations of the woods. Which epithets of the ancients, if you explore with the level of truth, you will see were them- selves not far wrong. (Tulp, Observationum Medi- carum, 1641, Bk. Ill, chap. 56, p. 277.) And later, after commenting on the false descriptions of the ancients, Tulp remarks: He who diminishes this faith, easily falls upon the sharp rocks of false accusations : and weakens the authority of his history by differing from ac- cepted opinion. Such injury formerly hissed, yet in the right way Herodotus endured, a writer, for the rest, not unbeautiful. From him therefore, as far as it could be done in so great shadows, Pliny culled out the best observations; and was Fig. 4. "Orang-outang," knuvvn tu have been a chimpan- zee. From Tulp, 1641. 12 A STUDY OF ANTHROPOID LIFE content to leave his satyr rather than the true one to posterity. But it was in the service of fame; and never can one freely retreat from opinions which have acquired age : nor from fables invented by the Poets. The coming of this Indian Satyr, perchance becoming famous, *may disperse their dense fog. It is difficult to please everyone. (Op. cit., pp. 278-279.) From the illustration found on page 275 of Tulp's book (our figure 4), and labeled Homo sylvestris, Orang-outang, one may with difficulty decide whether it was drawn from a chimpanzee or an orang-outan. Happily in this instance we know that the writer had first-hand acquaintance with a living specimen of chimpanzee and that the artist must have been at fault. We have given much attention to this author's contribution to knowledge of the anthropoid apes chiefly because his is the first obviously truthful, even if inaccurate, verbal and pictorial description of the chimpanzee. That he should have confused it with the orang-outan is neither surpris- ing nor particularly disconcerting, since identification is possible. The work of Tulp, nearly three centuries ago, marked definite and important changes in the character of anthropoid knowledge. Thereafter description became increasingly detailed and accurate, although for cen- turies confusion of types persisted. Only a few years after publication by Tulp, Jacob Bontius wrote unmistakably of the Bornean orang-outan, albeit with such general description and inaccurate illustration that the identification of his subject depends primarily on its source and on his account of its appearance and be- havior. Nevertheless Bontius, as truly rep- resentative of his times, is worthy of men- tion and quotation, if not also of censure for carelessness. Using for a different type of great ape the names Homo silvestris and Ourang Outang which Tulp had applied to the chimpanzee, Bontius with delightful sar- casm remarks: Goat-footed Satyrs, Sphinges, and frisky fauns. Not even boys believe in: Yet regard this won- derful monster with a human face, not only like the customs of man in speaking, but also in wet- ting his lips with weeping. (Bontius, Historiae Naturalis, 1658, Bk. VI, p. 84.) Then following a reference to Pliny, he continues: But yet what merits greater admiration, I my- self have seen several and of both sexes walking erect, first that young female satyr (whose figure I here exhibit) hiding her secret parts with so great modesty from unknown men, and also her face with her hands (if one may speak thus), weeping copiously, uttering groans, and expressing other human acts so that you would say nothing human was lacking in her but speech. The Java- nese say, in truth, that they can talk, but do not wish to, lest they should be compelled to labor: ridiculous, by Hercules. The name they give to it is Ourang Outang, which means a man of the woods, and they affirm that they are bom from the lust of the Indian women, who mix with apes and monkeys with detestable sensuality. Let boys believe, who have not yet to shave. {Op. cit., p. 85.) The illustration which as figure 5 we Fig. 5. Creature called "Ourang Outang," evidently a pilose woman. From Bontius, 1658. KNOWLEDGE THROUGH THE SEVENTEENTH CENTURY 13 have taken pains to reproduce from what purports to be the first edition of Bontius' book, instead of from later reproductions which were more or less altered, convinces one that the artist's model was a pilose woman. Especially worthy of remark is the criti- cal attitude of Bontius toward the fantas- tic imaginings of many of the ancients. In this he and Tulp evidently were sympa- thetic. Quoting with apparent approval certain earlier authorities whose facts we know to be few and whose descriptions grossly in- accurate, Nieuhoff refers to what may have been the gibbon. Except for the contribu- tion of Athanasius Kircher which appears in his volume, we probably should not have thought to include the name of Nieuhoff in this chapter. This description from Kircher has marked human interest. The Province Fokien hath an Animal perfectly resemblinfr man, but longer arms, and all over hairy, called Fese, most swift and greedy after humane flesh, which that he may the better make his prey, he feigneth a laughter, and suddenly while the person stands listning, sieseth. There are also in China Apes and Baboons of a different kind, whereof some imitate Men, others Dogs and Cats, and are also tractable and docile to admira- tion, of which take Father Roths relation, he be- ing an eye-witness. The King of Bengala in the year 1660 dispatched unto the Emperour of the Mogores a solemn Embassy, with many rich Pres- ents, amongst which was a Triumphal Chariot drawn by two white horses wonderfully adorned with Gold and Gems; but that which was more worthy admiration, the Charioteer was no humane Creature, for a great Baboon guided the Reins with no small skill and dexterity, his Livery Cloak and Cap shining with Scarlet and Gold, the Cham- pion, a great Mastive sitting on the highest seat as in a Throne of Majesty, decked and adorned with Gold and Jewels in so great splendour, that he looked upon himself as a Demi-god, and not a Dog; his Valets-de-chambre, Pages, and Lacquies, richly drest according to their place and office, were all Apes and Monkies, officiously attending round about him, who so well had learnt his les- son, that when any person of quality drew near, he not only performed due reverence, making low Congies, but his well instructed Life-guard did the like : which the Emperour beholding with great pleasure and admiration, caused a high Treatment to be prepared for them, where each had his own proper and peculiar Mess, where his Guests seated themselves with good order and gravity. This pleasant Comedy I saw acted in the Imperial Palace at Agra. (Nieuhoff, An Embassy from the East-India Company, etc., 1669, pp. 91-92 of appendix.) If our animal trainers surpass this achievement they do well! One suspects that gibbons or orang-outans, as well as monkeys, may have taken part in the pag- eant, and that the term baboon is used for some other than the animal now so desig- nated. We find in Olfert Dapper's description of Africa, vague references to a species of "Satyre" called by the Negroes "Quojas- Morrou" and by the Portuguese "Salvage." The description leaves us uncertain whether the gorilla or chimpanzee is meant, but the names and the following quotation con- vince us that Dapper had reference to the specimen of chimpanzee previously de- scribed by Tulp, It was thirty or forty years ago that one of these animals was sent to Holland and presented to his Highness, Prince Frederick Henry. It was the size of a child of three years, but was easily twice as broad, being of a good carriage, strong, vigorous, and agile ; for it Ufted heavy articles and carried them from one place to another. (Dapper, Description de I'Ajrique, 1686, p. 366. Originally published in Dutch in 1676.) Progress toward the really useful and ob- viously consistent classification of animals was even slower following the Dark Ages than the accumulation of descriptive infor- mation. From the time of John Ray (1628- 1705) it is reasonable to date the develop- ment of modern systematic zoology. He it was who, from the chaos of such enthusias- tic compilers and prolific writers as Gesner and Aldrovandi, produced order. The pub- lication of his Synopsis Methodica Ani- malium Quadrupedum et Serpentini Gene- ris in 1693 niarks the beginning of a new era for biology. Logical, consistent, and exact classification and nomenclature are absolutely essential conditions for the ex- tension and refinement of knowledge of organisms. Already we have presented am- ple evidence that anthropoid references and descriptions which do not permit certain 14 A STUDY OF ANTHROPOID LIFE identification are next to valueless. It is be- cause principles of classification and an ac- ceptable nomenclature were essential to the development of knowledge of the anthro- poid apes that we dwell appreciatively on the work of John Ray. Le Comte (1697, II, 361-364) offers very general descriptions of both types of Asi- atic anthropoid, the orang-outan and the gibbon. If it were worth while we might mention several other references of slight historical importance which, while indicat- ing acquaintance with one or other of the anthropoids, mark relatively slow progress in the extension of knowledge. As the work of Ray set a fashion for zoology and aroused enthusiastic interest in taxonomy, that of Tyson, distinguished comparative anatomist, marked the begin- ning of exact and detailed description of anthropoid structure. It was Tyson's merit to work discriminatingly, critically, and painstakingly. To close this chapter with mention of the epochal contributions of Ray and Tyson is peculiarly fitting. The former contributed only indirectly, but sig- nificantly, to the progress of anthropoid knowledge, the latter directly and to an extraordinary extent. In the foregoing chapter we had occasion to quote Tyson's opinion about Galen's use of anthropoid apes. Incidentally some of his ideas about the mythical character and confusion of ancient anthropoid lore were presented. We shall now attempt to char- acterize his "description of an orang- outang or pygmie." Tyson's Anatomy of a Pygmie is by far the most important contribution to anthro- poid knowledge prior to the eighteenth century. Widely and accurately acquainted with the writings of his predecessors, he was much more critical than they of mythi- cal data, inspired by a love of research, ex- perienced in dissection and anatomical de- scription, and disinterestedly concerned in the promotion of learning. In the preface to his book he remarks: And the Orang-Outang (whose Anatomy I here give) being a Creature so very remarkable, and rare ; and not only in its External Shape, but much more in the Conformation of a great many of the inward Viscera, so much resembling a Man ; I thought I could not be too particular, in Fig. 6. "Orang-outang or Pygmie," actually an immature chimpanzee. From Tyson, 1699. my Description of it; though to some, who have not a Tast of these Matters, I may seem prolix and tedious. (Tyson, 1699, preface.) Clearly perceiving the prevalent confu- sion of primate types Tyson intelligently and earnestly endeavored to set things right. In this connection his own words are of interest: That the Pygmies of the Antients were a sort of Apes, and not of Humane Race, I shall endeavour to prove in the following Essay. And if the Pyg- mies were only Apes, then in all probability our Ape may be a Pygmie; a sort of Animal so much resembling Man, that both the Antients and the KNOWLEDGE THROUGH THE SEVENTEENTH CENTURY 15 Moderns have reputed it to be a Puny Race of Mankind, call'd to this day, Homo Sylvestris, The Wild Man; Orang-Outang, or a Man of the Woods; by the Africans Quoias Morrou; by others Baris, or Barris, and by the Portugese, the Sal- vage. But observing that under these Names, they describe different Animals; for Distinction-sake, and to avoid Equivocation, I shall call the Sub- ject, of which I am about to give the Anatomy, a Pygmie, from its Stature; which I find to be just the same with the Stature of the Pygmies of the Antients. Tulpius 'tis true, and Bontius, and Dapper do call it, Satyrus. And tho' I am of Opin- ion, that the Satyrs of the Antients were of the Ape, or rather Monkey-kind; yet for the Reasons alledged in the following Essay, I cannot think our Animal a Satyr. The Baris or Barris, which they describe to be much taller than our Animal, probably may be what we call a Drill. But I must confess, there is so great Confusion in the De- scription of this sort of Creature, which I find is a very large Family (there being numerous Species of them) that in Transcribing the Authors that have wrote about them, 'tis almost impossible but to make mistakes; from the want of their well distinguishing them. I shall endeavour therefore in my Account of this, so to discriminate it, that it may be easily known again, where-ever 'tis met with. Not that I think in a single Observation I can be so exact, but that I may be liable to make Errors my self, how careful soever I have been. {Op. cit., pp. 1-2.) That the "pygmie" of Tyson was a chimpanzee is evidenced by its source, An- gola, in Africa, its skeleton, and the de- scription of its appearance, anatomy, and behavior. Our author recognized discrep- ancies in the accounts of the orang-outan given by Bontius and Tulp and seriously doubted whether they were describing the same creature. Actually we know now that Tulp wrote of the chimpanzee (as did Tyson also) and Bontius of the orang- outan. Although it does not particularly con- cern us as students of psychobiology, we are impelled to mention the conspicuous merit of Tyson's anthropometric and ana- tomical observations by contrast with those of most of his predecessors. From the Dark Ages and the early period of the revival of learning and re- awakening of interest in natural science, six names stand forth as associated with notable contributions to the literature on the infrahuman primates. They are: Ges- ner, Aldrovandi, Tulp, Bontius, Ray, and Tyson. Gesner and Aldrovandi supplied in- valuable compilations of information, Ray prepared the ground for an absolutely es- sential taxonomy, and Tulp, Bontius, and Tyson made progress toward increasingly exact description of the behavior, appear- ance, and anatomy of chimpanzee and orang-outan. CHAPTER THREE PROGRESS OF ACQUAINTANCE WITH THE ANTHROPOID APES DURING THE EIGHTEENTH CENTURY PRIOR to intimate acquaintance with the anthropoid literature we had planned to arrange our materials under types and to trace through the cen- turies the increase in knowledge of each in turn. As we proceeded with our task it be- came clear that this would necessitate far more repetition of reference and statement of fact than would a simple chronological presentation. In the foregoing chapter we have described typical or outstanding con- tributions in order of publication, but here- after we shall occasionally depart from the chronological order in considering signal and temporally approximated studies of a given type, topic, or method of procedure. In so doing we shall sacrifice logical con- sistency to what we hope may prove the convenience of the reader, intelligibility, clarity, and brevity. The farther we go in this historical sur- vey the more sketchy it necessarily be- comes and the fewer, relatively, the signifi- cant contributions which can be mentioned. In default of completeness of reference and review we have endeavored to indicate cor- rectly trends of interest, discovery, and method. It has been impossible to present any considerable part of the factual con- tent of publications. This material is more appropriate, however, in the later parts of the volume in which we deal in detail with scientific knowledge of each of the princi- pal groups of anthropoid ape. During the eighteenth century special zoological studies of the anthropoids be- came increasingly numerous. Previously, the contributions of lay writers of natural history, travelers, explorers, government agents, and those on special missions, had predominated. Perhaps the chief single cause for this radical change in the char- acter of anthropoid studies was the growth of a vigorous interest in zoological taxon- omy and resulting stimulation of observa- tion of the external appearance and in- ternal structure of animals. In any event the eighteenth century was far more impor- tant in its scientific progress than any previous period, and in it the second half, more significant by far than the first. The influence on anthropoid knowledge of the development of taxonomy or sys- tematic zoology demands further comment. Following the stimulating work of Ray at the close of the seventeenth century, there appeared during the eighteenth century three notable figures: Linnaeus, Buff on, and Cuvier. About each of these builders of zoology gathered disciples, critics, and in- dependent followers. We may mention only a few of the train who as classifiers, natu- ralists, or both, advanced knowledge of the anthropoid apes, or prepared the way for epochal progress by rendering the identifi- cation of subjects more certain. There are I. Klein (1751), Brisson (1756), Erxleben (1777), Blumenbach (1775, 1825), Pen- nant (1781), Vicq-d'Azyr (1792), E. Geo- ffroy-Saint-Hilaire and G. Cuvier (1795). As a general tribute to the work of this group of enthusiastic seekers for bases of classification and nomenclature, we may say that the fundamental importance of taxonomy is attested by the entire history of anthropoid research. If we should at- tempt to present adequately the anthro- poid materials and discussions published during the eighteenth century by taxono- mists, our chapter would stretch to a vol- ume. The contributions to anthropoid lore, in no way distinguished, from 1700 to 1750 are exemplified by the works of Bosman KNOWLEDGE DURING THE EIGHTEENTH CENTURY 17 (1705), Schouten (1707), Leguat (1708), Beeckman (1718), Careri (1727), Du Halde (1736), Boreman (1739), Scotin Fig. 7. "Singe" from Java, presumably intended to repre- sent the orang-outan. From Leguat, 1708. (1739), Smith (1744), and Barbot (1746). We shall utilize them to indicate the nature of interest and inquiry and the extent of progress in the first half of the century. Bosman, a traveler^ in describing the animals of Guinea mentions a fawn-col- ored creature, little shorter than a man, called in Flemish smitten. Do as I do, Sir, and believe whatever you wish to; one fact to which I can attest is that these animals are horribly wicked and seem to have been created only to do evil. . . . These monkeys have a rather ugly shape, as do the second species, which they would resemble in every respect were it not that scarcely a quarter of them are as large as the first species. The best thing that can be said of these monkeys is that they can learn nearly everything one wishes. (Bos- man, 1705, p. 259.) The orang-outan is described by Schou- ten, Leguat, and Beeckman without addi- tion to existing information, but with un- failing repetition of the superstitions of the natives. Beeckman for several months kept a young orang-outan with him. The draw- ing (fig. 8) which we have borrowed from his book certainly does not convict any one of accurate observation and delineation. There are numerous trivial and enter- taining references to the apes. For example, that of the voyager Careri, who recounts the old story of how apes or monkeys safely effect the destruction of large oys- Fig. 8. '-Ihe Oran-ootan" of Borneo. Irom Beeckman, 1718. i8 A STUDY OF ANTHROPOID LIFE ters by slipping stones between the open halves of the shell. (Careri, 1727, V, 155- 156.) In a compilation avowedly for the enter- Fig. 9. "Female Pygmy or Chimpanzee." From Boreman, 1739- tainment of the young, Boreman tells of the appearance and manner of life of the chimpanzee. His facts mostly are bor- rowed from Tyson. Referring to a female specimen which was brought from Angola to England in 1738, and which we with difficulty imagine to have been the subject of the drawing from Boreman's book (fig. 4, p. 22), reproduced herein as figure 9, that author writes: The Chimpanzee was very pretty Company at the Tea-table, behav'd with Modesty and good Manners, and gave great Satisfaction to the Ladies who were pleased to honour her with their Visits, by several rational and seemingly diverting little Actions; it would fetch its little Chair, and sit in it naturally, like a Humane Creature, whilst it drank Tea : It would take the Dish in its Hand, and if the Liquor was two hot, wou'd pour the Tea into the Saucer to cool it, and so in various little Things, mimick Man to a surpris- ing degree. (Boreman, 1739, p. 24.) Scotin observed the chimpanzee of 1738, and, still more important, engraved it on brass. We had almost quoted "skilfully en- graved" when a glance at the accompany- ing figure 10 (from Scotin, 1739, p. 564) inhibited us! Accounts of the chimpanzee, brief and obviously based largely on the reports of natives, are given also by Smith (1744), who presents a curious engraving (p. 147) of a creature called the Mandrill; and by Barbot (1746), in whose writings we find nothing but the usual commonplaces and fancies. The painter-naturalist Edwards (1758- 64) stands as a somewhat notable figure in Fig. 10. llie London chimpanzee of 1738. trom hcotin, 1739- KNOWLEDGE DURING THE EIGHTEENTH CENTURY 19 the history of anthropoid knowledge be- cause in addition to writing a readable popular description of the "man of the woods" he illustrated it with a figure en- Fig. II. Chimpanzee, orang-outan, or both? From Ed- wards, 1758-64. titled "The Satier, Sauage, Wild-man, Pigmy, Orang-outang, Chimp-anzee &c., A.D. 1757, Geo. Edwards, Delin.et Sculp.," in which he so skilfully mingled the struc- tural characters of orang-outan, chimpan- zee, and gibbon that one cannot more exactly name the figure than by the syno- nyms which the artist himself used. Whereas one portion of Edwards' descrip- tion refers unquestionably to the orang- outan, another is applicable only to the chimpanzee. In his illustration, which we present as figure 1 1 , the full-length drawing suggests the chimpanzee, whereas the pro- file resembles the orang-outan. It is but natural then that we should find it difficult to think of him as an anthropoid authority. In the Anthropomorpha of Hoppius (1760), who was a pupil of Linnaeus, one discovers a historical disquisition sugges- tive of the writings of Gesner and Aldro- vandi. Although the work marks progress in acquaintance with anthropoid types, contains some new information, and is in certain respects more critical and construc- tive than many similar writings of the six- teenth and seventeenth centuries, it gives the reader a lively impression of the mea- gerness and inexactitude of knowledge at that period. That Hoppius was acutely dissatisfied with the materials which he could com- mand is thus indicated: Since therefore no one, without extraordinary delight and wonder, can look upon the living genus of Simiae, so utterly ridiculous and curious, those just mentioned, which are most like men, should be studied with open minds by experts in natural history. Wherefore one comes to wonder how it has happened that man, eager to learn, has left them hitherto in darkness, nor has wished with so little reasonableness to know the Troglodytes, who are nearest to himself. Many mortals spend their days in the study of their appetites and de- sires and anxiously cogitate thus alone: in what manner they may heap up for themselves food and treasures howsoever scraped together; nor is the case different with the greatest part of those who seek the Indies in ships : to whom alone it happens that they see the genus of the Troglo- dytes : these, gaping with open mouths at so much wealth, think it beneath their notice to scrutinize the nature of natural objects and to explore their economy. But what, I ask, may be more con- veniently an object of delight, even to Monarchs themselves, than to contemplate the animals of their home close at hand, whom we can never ad- mire enough. Would it not be easy for the King, to whose will certainly a whole race bends, to get possession of them? It would lead not a little to Philosophy, if one were to spend a day with any of them, exploring how far human wit exceeds theirs, what distance lies between Brutish and ra- tional discrimination; so that, moreover, light would arise for students of natural science from a complete description of them. This concerns me, for I am doubtful by what characteristic marks the Troglodytes are distinguished from Man, ac- cording to the principles of natural history; so near are some among the genera of Men and Apes as to structure of body : face, ears, mouth, teeth, hands, breasts; food, imitation, gestures, especially in those species which walk erect and are properly called Anthropomorpha, so that marks sufficing for the genera are found with greatest difficulty. (Hoppius, op. cit., 2d ed., 1789, pp. 75-76.) 20 A STUDY OF ANTHROPOID LIFE Familiar with the lore of the ancients and the facts and superstitions of his own time, Hoppius described verbally and pic- torially four types of Anthropomorpha : Pygmaeus (uncertainly identifiable as the orang-outan), Satyrus (the chimpanzee), Lucifer (wholly imaginary), and Troglo- dyta (also imaginary). Although like his textual matter, the illustrations of Hoppius are borrowed from other authors, and that not without alterations, we have repro- duced as figure 12, for the entertainment and enlightenment of the reader, the draw- ings which appear on his page 76. Could one more impressively represent the status of knowledge of the anthropoid apes in the middle of the eighteenth century? The famous Natural History of Buffon (1749-67, vol. 14, 1766), written almost simultaneously with the Anthropomorpha of Hoppius, contrasts arrestingly with the latter. Aside from being delightfully writ- ten, it is a reasonably authoritative source of information which, therefore, we shall have abundant cause to refer to and draw upon in our later chapters. If the reader wishes a single reference for the materials of this chapter, and the historical period which it represents, it must be the work of the gifted French naturalist. Even those with training in a learned profession and in the natural sciences fre- quently have written mistakenly and, therefore, misleadingly of the great apes. Edward Bancroft, M.D., is an unfortunate example, for, relying too much on the truthfulness of the native Indians, he at- tributed to Guiana in South America an orang-outan "much larger than either the African or Oriental, if the accounts of the natives may be relied on." (Bancroft, 1769, p. 130.) We quote the last phrase in ex- tenuation. Yet one marvels that so utterly false a statement, from the pen of a physician, could have got into print so recently. While reading thus far in these histori- cal chapters many must have noted the paucity of references to gibbons and the lack of descriptive information. This defect is now to be partially remedied, for in the last half of the eighteenth century several KNOWLEDGE DURING THE EIGHTEENTH CENTURY 21 eminently useful accounts of the gibbon were published. We have selected as ex- amples those of de Visme (1769), Turpin Fig. 13. Male and female gibbons. From de Visme, 1769. (1771), and van Iperen and Schouman (1784). As occurring in the interior of Bengal, de Visme tells of the Golok, which we readily identify as a gibbon. His drawings, our figure 13, also represent a gibbon. We quote the following comment on de Visme's observations chiefly because of the point it gives to our remark about the value of Buffon's Natural History. The monkey, of which Mr. De Visme has sent this drawing and short account, seems to be very like, if not the same with the ape without a tail, described by Mr. De Buffon in the XlVth volume of the Histoire Naturelle, p. 92, under the name of the Gibbon, which it bears in some parts of the East-Indies. This species is found, he says, along the coast of Coromandel, at Mallacca, on the Molucca islands, and upon the confines of China. It grows to be upwards of four feet, walks on its hind legs, and sometimes on all four. The hair, with which it is covered, is either brown or black : round about its face is a circle of greyish hairs; its eyes are large, but sunk in its head; its ears naked; its face flat, and of a copper colour. It is of a placid disposition ; its motions are gen- tle; it was fed with bread, fruits, almonds. But the most singular characteristic is, the great length of its arms; and though Mr. De Visme takes no notice of this circumstance in his description, his drawing seems to indicate it ; but in a less striking manner than that of Mr. De Buffon, who adds, that, when the animal is upright, it can touch the ground with its hands. (De Visme, 1769, p. 73.) Among the "monkeys" of Siam, Turpin mentions the onke. It is the white-handed gibbon of current natural history. The au- thor's description of this animal's appear- ance and behavior, although brief, is use- ful. In a quite different category, scientifi- cally, than the contributions of de Visme and Turpin, is that of van Iperen and Schouman, who in 1784 published what appears to be the best early description of a species of gibbon. The native name for this creature, wau-wau (or wah-wah), these authors say is supposed by some to be taken from its resemblance to a little old woman, the meaning of the Javanese wah. They, however, believe that it is taken instead from the animal's cry. Although many authors previously had supplied descriptions of the gibbon suffi- Fig. 14. "The Great Gibbon." From liuffon, 1766, vol. 14. cient for general identification, it remained for van Iperen and Schouman to trace the history of the subject and to give a rea- 22 A STUDY OF ANTHROPOID LIFE sonably complete account of the appear- ance, sounds, general behavior, points of difference from other species, and physical measurement of the wau-wau. They state Fig. 15. The "Jocko" or chimpanzee. From Buffon, 1766, vol. 14. that the Javanese distinguish, chiefly on the basis of coloration, three species of which the wau-wau is the gray and black. It was natural that in contrasting the wau- wau with other species of gibbon they should come to question the practicability of classing it with them. Finally they con- cluded that wau-wau and gibbon are dif- ferent types of tailless ape. Considering the prevalent confusion of types and the abundance of contradictory statements, the contribution of van Iperen and Schouman must be regarded as of unusual scientific merit. The unprecedented taxonomic activity and progress of this period, with its ag- gressive search for characters useful in identification and classification, stirred in- terest in similarities and relationships. In- evitably there arose queries, arguments, disputes about the relationship of anthro- poid apes to man. Although many of the eminent systematists might fairly be men- tioned in this connection, the outstanding figure, because of his warmth and energy, is Monboddo (1773, 1784). Writing much and lucidly, although not always with un- impeachable logic and fairness, he reviewed for his own purposes much of the available information about anthropoid apes. In marshaling facts relative to relationships he proved to his satisfaction the close struc- tural and psychobiological similarity be- tween man and great ape, and insistently argued that speech is not distinctively human. Contrasted with Monboddo, the philo- sophically minded, is Long, the historian, who in 1774 while recounting the history of Jamaica, a land wholly devoid of an- thropoids, became engaged with the per- plexing problem of relations, and discussed it both intelligently and with fair com- mand of information. Although he also was keenly interested in relations, it would be grossly misleading to class Blumenbach with Monboddo and Long, since he approached the subject rather by giving impetus to anthropological observation than by speculative argument or historical description. One finds many excellent comparisons of structure and be- havior and various well-founded arguments in Blumenbach 's On the Natural Variety of Mankind (1775), along with generally reliable, but in the main secondhand, his- torical and descriptive anthropoid mate- rials. The intellectual quality of this au- thor and his bias concerning relationship are made clear by these few sentences: It is indeed beyond all doubt that the fiercest nations, the Californians, the inhabitants of the Cape of Good Hope, &c, have a peculiar sort of speech, and plenty of definite words, and that ani- mals on the contrary, whether they be like man in structure, as the famous orang-utan is, or ap- proach man in intelHgence, to use the words of Pliny about the elephant, are destitute of speech, KNOWLEDGE DURING THE EIGHTEENTH CENTURY 23 and can only emit a few and those equivocal sounds. That speech is the work of reason alone, appears from this, that other animals, although they have nearly the same organs of voice as man, are entirely destitute of it. (Blumenbach, 1775, quoted from 1865 ed., pp. 83-84.) Another property of man comes directly from the foregoing, namely, his two hands, which I consider belong to mankind alone; whereas apes, on the contrary, must either have four or none at all, of which the great toe being separated from the other fingers of the feet serves the same pur- poses which the thumbs do in the hands. This is so certain, that on that account alone the foetus said by Robinet to be that of a pongo, must certainly be considered a human embryo, even if no notice be taken of the other propor- tions of the bodily parts, and the whole structure which is entirely human. (P. 86.) Although "relationship" during the eight- eenth century attracted the attention of many, and monopolized that of a few, able individuals, it was not until the nineteenth century that it became a dominant intel- lectual issue. The chief factual contribu- tions for which it may be held responsible in the eighteenth century are studies of the vocal mechanism, speech, or other forms of vocalization, and the characteristics of hand and foot in anthropoid apes as com- pared with man. In the second edition of his remarkable essay on The Origin and Progress of Lan- guage (1774) Lord Monboddo inserted a letter from a former "captain of a ship trading with the slave coast of Africa" in which the gorilla is mentioned among three "classes or species" of African apes. Of this animal there are three classes or species ; the first and largest is, by the natives of Loango, Malemba, Cabenda, and Congo, called or named Impungu. This wonderful and frightful produc- tion of nature walks upright like man; is from 7 to 9 feet high, when at maturity, thick in propor- tion, and amazingly strong; covered with longish hair, jet black over the body, but longer on the head; the face more like the human than the Chimpenza, but the complexion black; and has no tail. (Monboddo, 1774, I, 281.) The Impungu of this letter, in our opinion, is the gorilla, for in addition to describing the giant ape consistently, the author contrasts it with the chimpanzee. Apparently Monboddo has supplied the only unmistakable and scientifically use- ful reference to the gorilla in the literature of the eighteenth century. To Vosmaer, Camper, and Wurmb we owe the signally important original contri- butions of the century. While others for the most part were content to recount the stories of natives, with a few original obser- vations thrown in, or to re-present materials already many times printed, these three, Dutchmen all, relied on original inquiry, and as anatomists made themselves inti- mately acquainted with the appearance, structure, and many aspects of the be- havior of the orang-outan. Vosmaer's historical introduction to his description of a very rare and odd species of monkey (1778) indicates his inability to distinguish the African chimpanzee from the Asiatic orang-outan. This, however, is not to be wondered at. While doubting even the existence of the rumored "great orang-outan," for twenty years he dili- gently sought reliable information about it, or a living specimen. In 1776, he suc- ceeded in obtaining one from Borneo. His 24 A STUDY OF ANTHROPOID LIFE account of the appearance, daily life, and behavior of this specimen is of finer sci- entific quality than much of the more re- cent behavioral work with anthropoid apes. Because the publication of Vosmaer is of wholly exceptional importance, and pre- eminently worthy of use in our later spe- cial discussion of the behavior of the orang- outan, more lengthy exposition or comment in this historical chapter is inappropriate. The orang-outan is the subject also of a valuable contribution by Camper. From his excellent historical introduction one dis- covers that he had read critically the prin- cipal works of his predecessors, and unlike most of them had dissected the orang- outan as well as several other primates. Of identification he pertinently and plainly remarks : It is useless to repeat here what has already been written of this species by Buffon (vol. 14, p. 48), inasmuch as this great and indefatigable naturalist, never having seen a real Orang, — one from Borneo — , was induced by an error of Tul- pius and Tyson, to place this great tailless, Afri- can ape in the kingdom of Angola and in Guinea, among the true Orangs, from which they differ considerably, as we shall show. That which has been said of the African apes, that which has been recounted by voyagers of Pongos, Jockos, etc., cannot, under any condition, be applied to the animal in question; I shall not adopt much of what has been alleged in this re- spect by the general nomenclators, by Linnaeus, for example, and by his pupil Hoppius, of the simple conjectures, the miserable reports and false descriptions. I say the same of Brisson and, in short, of all the authors. These writers never saw the Orang of Borneo, when they undertook to give them names, and they were, in spite of them- selves, mistaken, because they never gave a clear and exact description of this rare and unique ani- mal. Edwards is the only one who can be consid- ered to have written something with certainty; but, as he was neither an anatomist nor a natu- ralist, and only a very mediocre painter, he gave us only a very poor description and a still worse illustration. He observed correctly, however, that Tyson's illustration of the Orang was by no means satisfactory; but that a certain Captain Beeck- man described, in the voyage to Borneo, made in 1 718, an Orang, which, though similar to his own, was not quite the same; for, in truth, it could not be the same creature, if it is true that this animal was covered with hair in the places thought to be characteristic of human beings, since it is on the back and on the outside of the legs and arms that the Orang is the most hairy, as Aristotle has already observed. (Camper, 1779, from 1803 ed., I, 44-46.) We have quoted thus at length to indi- cate at once the persistent confusion of types and our author's critical acumen. Fi- nally, as basis for his great contribution to our knowledge of the anthropoids Camper possessed a fund of information gathered from the study of living specimens, meas- urement of cadavers, and complete dissec- tions. Although his descriptions of behavior are useful, his morphological contribution is of surpassing value because he was pri- marily an anatomist. In concluding the anatomical section of his book Camper writes: I believe I can conclude, after enumerating all the external and internal specific characters in such great number in the Orang, which I have described and illustrated with the most scrupulous exactitude, that: First, the Orang differs greatly from Man as much in shape as in height, and in behavior; that he is unable to speak or to sit down like man, or to he on his back, and still less to grasp anything, because his thumb is much too short. Secondly, that the Orang is actually a quad- ruped, with great similarity to certain monkeys (singes), such, for example, as the Gibbon, and the Pygmy of Tyson, but that, on the other hand, he differs from them greatly in vocal organs, and in the skeletal arrangement of the hands and- other parts of the body; that he is furthest re- moved from the Pithecus, above all in vocal or- gans, shape of the body, intestines, and in skele- ton, particularly that of the hands. The Orang-Outang of B&rneo is consequently an animal which should be placed in the general class of monkeys (singes) or four-handed animals (quadrumanes) ; but which however forms a to- tally disinct species. {Op. cit., pp. 145-146.) In a briefer communication transmitted to the Royal Society of London, and pub- lished in the same year with his epoch- making book on the orang-outan. Camper discusses the structure and functions of the "organs of speech" of the orang-outan. His conclusion, however well it may then have seemed to be founded, sounds to the present-day reader dogmatic and overin- clusive. Having dissected the whole organ of voice in the Orang, in apes, and several monkies, I have a KNOWLEDGE DURING THE EIGHTEENTH CENTURY 25 right to conclude, that Orangs and apes are not made to modulate the voice like men : for the air passing by the rima glottidis is immediately lost in the ventricles or ventricle of the neck, as in apes and monkies, and must consequently return from thence without any force and melody within the throat and mouth of these creatures : and this seems to me the most evident proof of the inca- pacity of Orangs, apes, and monkies, to utter any modulated voice, as indeed they never have been observed to do. (Camper, 1779a, p. 155.) Grave misgivings about the correctness of some of Camper's conclusions do not les- sen our admiration for his contribution of fact. Together he and Vosmaer, by con- spicuously impressive example, established a new and highly profitable fashion in an- thropoid research. The interesting story of the capture of the "great orang-outan" (adult) finally studied by Vosmaer, is told by Rader- macher, who after listing the known speci- mens, presumptively of orang-outans, and inviting attention to their small size, ap- proximately two and one-half feet in height, continues: The large species, described by Buffon and other authors as of the size of a man, is held by many to be a chimera. And perhaps this would have long been a riddle, if Palm, merchant and resi- dent of Rembang, in his journey from Landak to Pontiana, had not shot one and sent it, in hquor, to Batavia, which same by the Batavia Co. was immediately sent to Netherlands to Heer A, Vos- maer for the collection of His Illustrious Highness. Heer Palm wrote me as follows : "Herewith you receive, against all expectation, (altho I had previ- ously offered more than one hundred ducats to the Borneans and Banjarees for an orang outan of four to five feet) one which I killed about eight o'clock in the morning in this region. Long have we been busy, with every means thought of, and in the deepest wilderness, about half way to Landak, to capture this terrible creature alive. Moreover we have this day been more beset to hold him, at once taking care that we should not be hit by him; the while he incessantly broke green branches in pieces and threw them at us. This game lasted until four o'clock in the after- noon ; then we decided to give him the bullet : maybe in this I succeeded too well, a better than I has not always shot at such a mark; the bullet went just in the side in the upper part of the body, and thus is the animal little harmed. We brought him yet living in the piroque, bound him to the posts of the roof of the quay which served us as a tent ; where in the morning when we went to get him, he was found dead." (Radermacher, 1780?, quoted from 3d ed., 1826, pp. 65-66.) Evidently before this orang-outan was sent to Holland it was examined by Wurmb (1781) whose careful account of its exter- nal appearance, including a long list of physical measurements, together with a his- torical discussion, was published in the same volume as the article by Rader- macher just quoted. That Wurmb 's de- scription of the "great orang-outan" was deemed of peculiar scientific importance is evidenced by the fact that Jansen (1796) translated it from Dutch into French, and in 1798 it was translated into English for publication in the Philosophical Magazine. In the same year it was adversely criti- cized by Geoffroy-Saint-Hilaire, who be- lieved that instead of "the large orang- outan or Pongo" Wurmb had discovered a new species of ape. I shall not pursue any farther an explanation of the characterising marks which it exhibits to natu- ralists. I have said enough to prove that it is not the orang outang or pongo, but that it ought to be considered as a species unknown before the publication of Wurmb's memoir. I am far from reproaching that observer for his mistake. At the time when he wrote his description the natural history of the orang outangs was involved in such obscurity, that he must naturally have considered his ape to be the same animal as the large orang outang or pongo of Buffon. Naturalists were then far from being convinced that this animal, such as it is described in the immortal work of that cele- brated author, is an imaginary being to which Buffon has assigned a form and characterising marks, by confounding, under the same name, and in the same description, six different species of apes described by travellers. (E. Geoffroy- Saint-Hilaire, 1798a, pp. 341-342.) Although we have mentioned only the more important and, for one reason or an- other, typical publications of the period, we have all but finished our survey of progress in anthropoid research during the eighteenth century. Despite growing inter- est and increased enthusiasm for the col- lection and study of specimens, the three principal known types of anthropoid ape were generally confused even at the end of the century. The gorilla, as a scientific ob- ject, was practically unknown; the gibbon 26 A STUDY OF ANTHROPOID LIFE was uncertainly known because of contra- dictory descriptions attributable to differ- ent species, and the chimpanzee and orang- outan continued to be confused, partly be- cause of the long standing assumption of two varieties, the black in Africa and the red in Asia. It will profit us historically to take our end-of-the-century orientation from the systematists. Turton's translation of Gme- lin's edition of the Systema Naturae of Linnaeus mentions under the Simla six sorts of tailless ape: (i) Troglodytes, the black-coated ape from Angola (probably a chimpanzee, barely possibly the gorilla). (2) Satyrus, of which there are three spe- cies; (a) the red-coated ape of Borneo (then and now called orang-outang); (b) a second species or type of Satyrus called Pongo, found in Java and Guinea and of much greater size than the Bornean orang- outang (this also may refer to the adult orang-outang, chimpanzee, or gorilla) ; (c) a third species of Satyrus smaller than either of the others (possibly the immature Pongo). (3) Lar, long-armed apes (which we recognize as gibbons), found in India. Three species are mentioned which are dis- tinguished by differences in color mark- ings and size. (4) Sylvanus, the Pigmy of Africa and Ceylon (possibly this also re- fers to the chimpanzee). (5) Inuus, the African Magot (our Barbary ape). (6) Suilla, the hog-faced ape (undoubtedly a species of monkey). (Linne, 1806, I, 10- II.) That it is not easy to identify the vari- ous types of ape mentioned by Gmelin is obvious. Kerr, in his translation of Gme- lin's Linnaeus, lists as Simiae: (i) Chim- panzee, S. troglodytes, great ape; (2) Orang-outang, 5. satyrus, Homo sylves- trius; (3) Pongo, S. satyrus pongo, also called Homo sylvestrius and orang-outang; (4) Jocko, S. satyrus jocko; (5) the Great Gibbon, S. longimana, the long-armed ape. (White, 1799, pp. 29-31.) Pennant, adversely critical of the system of Linnaeus, proposed in his History of Quadrupeds (1781) seven divisions of the Fiu. 17. "Lont: -armed Aiif," doubtless a gibbon. From Pennant, 1793. tailless ape: Great apes. Pigmy apes, Long- armed apes (Lesser and Malacca), Golok, Lar, Barbary, and Hog-faced. One readily discovers in this list the adult manlike apes as "great apes," their young as "pigmy apes," and three species of gibbon as "long- armed apes," "Golok," and "Lar." Neither the Barbary nor the hog-faced ape belongs to the group of anthropoids as at present defined. (See 3d ed., 1793, of Pennant.) It seems almost incredible, yet it is evi- dently true, that with all their descriptive and taxonomic efforts the scientists of the eighteenth century made small progress to- ward the satisfactory and certain identifi- cation and classification of the four types of anthropoid ape then, as now, existent. CHAPTER FOUR THE EMERGENCE OF THE GORILLA OUR task of tracing the growth of I scientific knowledge of the anthro- poid apes to the time when all of the types were definitely recognized and distinguishable remains incomplete. At the Fig. i8. The chimpanzee, misnamed "Pongo" by the au- thor. From Audebert, 1800. end of the eighteenth century confusion still reigned and the gorilla was virtually unknown. In this chapter we shall depart farther than heretofore from the simple chronological arrangement of our materials in order to indicate with brevity informa- tional trends and advances with respect to topics and types. Our principal theme will necessarily be the scientific discovery of the gorilla. The period covered extends ap- proximately to 1865. Thereafter scientific study of the anthropoid apes rapidly be- came systematic, specialized, and intensive. Contributions marking the transition from the spirit of the eighteenth century to that of the nineteenth, and also typical of the early years of the new century, are those of Audebert (1800) and Shaw (1800), the former essentially an artist, the latter a zoologist. Following in the foot- Fig. 19. The orang-outan (immature), by the author mis- named ''Jc'cko." From Audebert, iSoo. This is from an ex- cellent colored plate. Steps of Buffon, Audebert undertook to de- scribe the known primates and to picture them accurately from life. Shaw, by con- 28 A STUDY OF ANTHROPOID LIFE trast, was a masterly assembler of infor- mation who in his fourteen-volume general zoology presented the anthropoid informa- Fig. 20. The gibbon "Simla lar." From Audebert, 1800. tion of his time. Because of the admirable quality of their expositional labors, these two writers, though otherwise sharply con- trasted, belong together. They are equally worthy of consultation and reference. From them we may appropriately take our topi- cal departure, since original, as contrasted with compilational, publications became in- creasingly numerous and important as the century advanced. Neither Audebert nor Shaw was entirely clear as to anthropoid types, relations, and characters, and neither recognized the existence of the gorilla. Previously we have remarked that classi- ficatory or taxonomic interest and effort follow upon, and perhaps spring from, crude and undifferentiated naturalistic ac- tivity. Similarly in the anthropoid research of the nineteenth century we observe morphological interest arising from and rapidly supplementing the taxonomic. Quickly it gained headway and became a new zoological fashion, so that the century presently came to seem preeminently the era of morphology. In these reflections we are not overlooking the growth and direc- tive influence of the Dutch school of anatomy in the previous century. Although this volume is devoted to an- thropoid behavior we cannot fairly omit mention of the nature and influence of taxonomic and anatomical contributions. In the nineteenth century G. Cuvier, Blumen- bach, Illiger, the Geoffroy-Saint-Hilaires, de Blainville, and Owen are conspicuous for their contributions to zoological sci- ence, and each assisted notably in the ad- vancement of knowledge of the anthropoid apes. They introduced ideas, methods, hypotheses, and through admirable con- structive effort and the marshaling of facts radically altered the status of their sci- ence. Although many other able biologists during the early years of the century aided in developing and perfecting the classifica- tion and morphological description of the anthropoid apes, de Blainville and Owen Fig. 21. The "Moloch," perhaps the gray gibbon or wau- wau, Hylobates Icuciscus. From Audebert, 1800. for many reasons deserve special mention. The one contributed abundantly to his- tory, taxonomy, and anatomy; the other. THE EMERGENCE OF THE GORILLA 29 with remarkable accuracy, energy, and clarity, to anatomical description. Excellent general and naturalistic ac- counts of the anthropoid apes appear to be distinctive of the period. Better than any other sources they indicate the growth of knowledge and the trends of interest. The reader who would quickly and with mini- mum effort make himself master of what was known about the apes in the second quarter of the century cannot do better than read carefully the Natural History of Monkeys, Opossums, and Lemurs (1838),^ and Martin's General Introduction to the Natural History of Mammiferous Animals (1841). These books should be in the U- brary of every student of primate behavior. Unfortunately they are rare and relatively little known. The general description of anthropoid life by Boitard (1842), al- though of the same period, is less satisfac- tory than the works of Rennie and Martin, whereas the more recent and more widely known natural history of Brehm (1864-69) is preeminently useful. Anyone who reads in order Gesner (1551), Buffon (1766), Rennie (1838), Martin (1841), and Brehm (4th ed., 1922) on the anthropoid apes will experience a series of impressions covering the charac- teristics of human interest, the nature and methods of inquiry, and the scope and re- liability of information during successive periods. We strongly recommend this in- tellectual recreation to any reader who may wish to supplement our brief historical out- line. In the nineteenth century confusion of orang-outan and gibbon does not appear, but separation of chimpanzee and orang- outan was less definite and certain. This defect in systematic knowledge and prac- tice rapidly corrected itself, and in most of the reputable scientific contributions of the century the African anthropoids are recognized as distinct from the Asiatic. It was in 182 1 that Traill described the 1 This anonymous work, published in a series called "The Menageries," is attributed to James Rennie and by us listed under his name. anatomy of the chimpanzee under the name of "orang-outang." The confusion, however, existed in name alone, for this author dis- tinguished from his African specimen the Indian brown orang-outan. The narrative of a journey through China by Abel (1818) contains a service- able account of the history of acquaintance with the Bornean orang-outan, together with description of certain aspects of be- havior. This author also deemed it neces- sary to direct attention to the confusion of the Bornean orang-outan with the African ape, which he states to be the "Pongo." Later Abel (1825) published an account of the capture of a huge male orang-outan. With recourse to physical measurements and drawings he described the "remains." Especially emphasized in this contribution are the size ("a full head taller than any man on board") and the extraordinary tenacity of life of this creature when mor- tally wounded. Further clarifying accounts of the struc- ture, mode of Hfe, and behavior of the orang-outan are found in Jeffries (1825), Grant (1828), Tiedemann (1827), who compared the brain of the orang-outan with that of man, Temminck (1835-41)^ who acceptably monographed the primates,, and Schlegel and Miiller (1839-44). James Brooke, in a letter read before the London Zoological Society in 1841, an- nounces the shipment to London of five live orang-outans and states that he can prove the existence of two, if not three, distinct species in Borneo. His communication con- tributes also to the natural history and morphology of the ape. Pursuing his interest in species and geo- graphical distribution, Fitzinger (1853) reviews the history of the orang-outan in scientific literature and concludes from the records and his own observations that there probably exist two species in Borneo and two in Sumatra. These typical and important contribu- tions, selected from many which would be mentioned in an exhaustive study, fairly represent trends of interest, inquiry, and 30 A STUDY OF ANTHROPOID LIFE progress. They have been selected to mark decisively the achievement of such knowl- edge of the orang-outan that confusion was Fig. 22. Drawing of a gibbon. From Harlan, 1825. rendered impossible and the differentiation and identification of species facilitated. With the gibbon the case is different, because of the multiplicity of species and the consequent greater difficulty in obtain- ing adequate taxonomic data. Though this ape was known to the ancients even earlier perhaps than the orang-outan, and to sci- ence at least as early, progress toward ade- quate knowledge of it has been slower. Prior to the nineteenth century three or four apes, identifiable by us as gibbons. had been described, and in the early years of the century this number was increased to half a dozen. During the first half of the nineteenth century general acquaintance with the genus and its several species was furthered more or less notably by Raffles (1822), E. Geoffroy-Saint-Hilaire and F. Cuvier (1824), and Horsfield (1824). An exceptionally interesting description of a male specimen of Hylobates syndactyla is given by Bennett (1834). However, even as late as 1834 Lewis could write as follows: These animals have been placed, by recent sys- tematic naturalists, as a sub-genus of the Ourangs, with which they were confounded by the earlier writers. But their organization demonstrates much more recession from the great standard, man, than the latter, more especially in the elongation of the anterior extremities, and their dental peculiarities. Illiger, a Prussian anatomist, has designated them under the term HYLOBATES, to express their habits as inhabitants of the forests, and some re- markable additions have been made to the genus, so that five species have been described by Les- son in his supplement to Buffon, viz., H. Syn- dactylus, the Siamang; H. Lar, the Great or Black Gibbon; H. Leuciscus, Moloch or Cinere- ous Gibbon; H. Variegatus, Little Gibbon or Wouwou; H. Unko, the Ounko. To which num- ber Dr. Harlan, of Philadelphia, added another which he termed Concolor. (Lewis, 1834, p. 32.) This taxonomic misadventure is surpris- ing in view of the materials available. For although the literature on the gibbon was scanty and unsatisfactory, even by com- parison with that on the orang-outan, it offered no obvious excuse for placement of the two animals in the same genus. General systemic, naturalistic, and ana- tomic works provide ample evidence that by the middle of the century (see Elliot, 1913, III, 150 ff.) the structure and natu- ral history of the gibbon were known as intimately, if not as fully and accurately, as those of the orang-outan and chimpan- zee. The statement does not apply to be- havior, because the relative delicacy of the animals had prevented their successful transfer to Europe and limited opportuni- ties for observation of living specimens. As a matter of fact confusion of orang- outan and chimpanzee very nearly ended THE EMERGENCE OF THE GORILLA 31 with the previous century and it is some- what misleading, and unfair to zoological authorities of the period, to exhibit in- stances of its persistence. Nevertheless they occurred. By 1850 significant inquiries already mentioned, including those of leading sys- tematists and anatomists, had established separate genera for chimpanzee, orang- outan, and gibbon. Explanation of the long persistent confusion of chimpanzee and orang-outan, and insistence on their asso- ciation in a single genus, is found in the remarkable differences between the young and the adult stages of these manlike apes and the extreme difficulty of scientific ob- servers in getting trustworthy information about either stage of development or source of specimens. Definite knowledge of the gorilla is pe- culiar in several respects but chiefly in its recency. As object of scientific study this ape simply did not exist at the beginning of the nineteenth century, and it was not until the middle of the century that it was definitely described and generally accepted as a new genus of anthropoid ape. As an introduction to the following chronological account of the history of sci- entific acquaintance with the gorilla we shall briefly review what may be considered prescientific references to the animal. We consider those which we shall present sam- ples, for we lack even the desire to present a complete list of the works of explorers, travelers, adventurers, hunters, and others in which more or less definite and unmis- takable reference to the giant ape appears. Hanno's description of the gorilla in the fifth century, b.c, we have already (p. 3) cited as in our opinion inapplicable. The next mention of a large unidentified ape is that of Battell (Purchas, 1625), whose "Pongo" surely was the gorilla, while the native term engeco used by him (p. 10) designates the chimpanzee. The third plausible reference has been overlooked or for other reasons neglected by most his- torians. It is to be found in the second edition of Monboddo's work on language (1774) as already quoted (p. 23). The evidence convinces us that the gorilla was the object of remark by Monboddo's in- formant and that he had reasonably re- liable although scanty information. It is difficult to understand why this letter, when published in so important a book as that of Lord Monboddo, should not have stirred naturalists and adventurers to de- termined search for the giant ape. Some forty years later Bowdich (1819) in his Mission from Cape Coast Castle to Ashantee wrote thus of the African anthro- poid apes: The African Ourang-outan (Pithecus Troglo- dites) is found here, the one I saw was two feet and a half high, but said to be growing. I offered a fair price for it, considering they are not rare there, and would not give more when I heard of one being already in England. The native name is Inchego : it had the cry, visage, and action of a very old man, and was obedient to the voice of its master; its agony on espying the panther on board was inconceivable. There is a curious va- riety of monkeys. The favourite and most ex- traordinary subject of our conversations on natu- ral history, (which I introduce merely to excite enquiry) was the Ingena, compared with an Ourang-outan, but much exceeding it in size, be- ing generally five feet high, and four across the shoulders; its paw was said to be even more dis- proportionate than its breadth, and one blow of it to be fatal; it is seen commonly by those who travel to Kaylee, lurking in the bush to destroy passengers, and feeding principally on the wild honey, which abounds. Their death is frequently accelerated by the silliness which characterizes most of their actions : observing men carry heavy burthens through the forest, they tear off the largest branches from the trees, and accumulating a weight (sometimes of elephants teeth,) dispro- portionate even to their superior strength, emu- lously hurry with it from one part of the woods to another, with little or no cessation, until the fatigue, and the want of rest and nourishment, exhausts them. (Bowdich, 1819, pp. 440-441.) In the light of what we now know of the native names for chimpanzee {engeco) and gorilla (engena), it is wholly reasonable to infer that the extraordinary subject of con- versation was the gorilla. Yet even this unmistakable reference, perhaps because it appeared in a general account of the king- dom of Ashantee instead of in a biological 32 A STUDY OF ANTHROPOID LIFE publication, failed to discover the giant ape to scientists. Another quarter century and the gorilla actually emerged! Its discovery is owing primarily to the naturalistic interest of Protestant missionaries and their personal contacts with eminent anatomists. Wilson and Savage are the missionaries to whom chief credit belongs, Wyman and Owen their scientific collaborators. Jointly, in 1843-44, Savage and Wyman had pub- lished observations on the external charac- ters and habits of the chimpanzee Troglo- dytes niger, Geoff, and in 1847 their co- operation led to brief description of the appearance, habits, and cranial structure of the Enge-ena, which obviously is one spelling of a local name for the gorilla. Savage in the same year had sent to the English anatomist Owen some drawings of the skull of a form of ape which he pro- posed to call Troglodytes gorilla in dis- tinction from Troglodytes niger, the chim- panzee. The publication of Savage and Wyman stands as the first scientific account of the gorilla. As such it is worthy of quotation. The opening paragraphs are of peculiar in- terest as showing inadequate knowledge of the taxonomic literature of the period. Four species of anthropoid Simiae, commonly known as Orangs, have been described by natural- ists; of these, three are found in the eastern world, either on the continent of Asia, or the islands of Borneo, Sumatra and Java, and a fourth on the western coast of Africa. In the East there exists I. Simia satyrus, Lin. Pithecus satyrus, Geoff.; S. Abellii, Fisch.; L'Ourang outang, Cuvier; Red ourang. This is the species most fre- quently exhibited in an immature condition, in America and Europe, and is obtained in Cochin China, Malabar, and Borneo. II. S. Wurmbii, Fisch. Pongo Wurmbii, Kuhl. Grand Ourang-outang, Geoff. Dusky orang; from Borneo. III. S. Morio, Owen. Of this species the cranium has been described by Prof. Owen, but its external characters are not yet well known to naturalists. In Africa is found IV. Troglodytes niger, Geoff. Chimpanzee, Black Orang, Enge-eco, Jocko. This doubtless is the Barris of Pyrard de Laval, the Smitten of Bosman, Quinipe.se of De la Brosse, and the Quojas moras of Tulpius. The existence of a second species in Africa, does not appear to have been recognized by naturalists, nor in fact has there been hitherto adduced any evidence on which its existence might be predi- cated, except the vague statements of the different voyagers and travellers. But these, resting princi- pally on information derived from the natives, and not on the personal observation of the nar- rator, are in general so mingled with absurd and marvellous accounts, that they have been deserv- edly regarded as unworthy of credence. (Savage and Wyman, 1847, pp. 417-418.) Continuing, the authors express their opinion that the Pongo of Battell is prob- ably identical with their Enge-ena and state that: The "Ingena," referred to by Bowdich, in his mission to Ashantee, is probably the Enge-ena of the natives of the Gaboon, though his statement, that the animal was "five feet high and four across the shoulders," detracts from the credibility of his narrative. Whatever doubt may have here- tofore existed, the following notices of the habits, and external characters, and descriptions of the crania and some of the bones, will serve most satisfactorily to confirm the statements of Battell and Bowdich, with regard to the existence of a second African Orang, and to demonstrate that it is as specifically distinct from the Troglodytes niger, as from the Orangs of Borneo and Sumatra. The specific name, gorilla, has been adopted, a term used by Hanno, in describing the "wild men" found on the coast of Africa, probably one of the species of the Orang. (Pp. 419-420.) The killing of an Enge-ena is considered an act of great skill and courage, and brings to the vic- tor signal honor. A slave to an Mpongwe man, from an interior tribe, killed the male and female whose bones are the origin of this article. On one occasion he had succeeded in killing an elephant, and returning home met a male Enge-ena, and be- ing a good marksman he soon brought him to the ground. He had not proceeded far before the fe- male was observed, which he also killed. This act, unheard of before, was considered almost super- human. The man's freedom was immediately granted to him, and his name proclaimed abroad as the prince of hunters. It is said that this animal exhibits a degree of intelMgence inferior to that of the Chimpanzee; this might be expected from its wider departure from the organization of the human subject. I could not ascertain that more than one or two at most of the young had ever been captured. One was taken and kept for a year by a native, and then sold to a Frenchman, but it died on the THE EMERGENCE OF THE GORILLA 33 passage home. Whether the skeleton was preserved is not known. No information respecting its habits in a state of domestication could be had upon which reliance might be placed. (P. 425.) The authors conclude: From the preceding descriptions there can be no reason to doubt that the Enge-ena is specifically distinct from the Enche-eco or Chimpanzee, the only member of the sub-genus Troglodytes hith- erto recognized by naturalists. From the Enche- eco it is readily distinguished. (P. 436.) This historical landmark in anthropoid literature includes a table of comparative physical measurements for orang-outan, chimpanzee, gorilla, and man. Meanwhile, the distinguished anatomists Jeffries Wyman, of Boston, and Richard Owen, of London, were simultaneously en- gaged in examining evidences for the ex- istence of a type of anthropoid ape new to science. But whereas the former, thanks to assistance of the missionaries, Wilson and Savage, had crania and other skeletal parts for study, Owen initially based his conclu- sions on drawings of the skull. At first he Fig. 23. Drawing of a young gorilla. From I. Geoffroy- Saint-Hilaire, 185 1. declined, with justifiable conservatism, to believe a new species had been discovered. Subsequently and after careful study of osteological materials, he decided that they so far differed from Troglodytes niger as to justify the establishment of a species. Fig. 24. Adult gorilla and young. From Gervais, 1854. which in honor of its discoverer. Savage, he proposed to call Troglodytes savagei (Owen, 1859). In the course of the next few years Owen published several important studies of the gorilla which, although primarily morpho- logical, contain certain valuable observa- tions on behavior and natural history (1859a, 1 86 1, 1866). An important mem- oir appeared in 1865. In 1 85 1 Isidore Geoff roy-Saint-Hilaire announced to his scientific colleagues re- ceipt by the Museum of Natural History in Paris of two preserved specimens of ape called in the Gaboon Gina or Engina and belonging to the species, so remarkable and still so little known by naturalists, desig- nated as gorilla. This note was published in 1852 and in it the author tells us that 34 A STUDY OF ANTHROPOID LIFE since 1828 his father, Etienne Geoffroy- Saint-Hilaire, had suspected the existence of a second type of African ape. Further account of the characteristics of Troglodytes gorilla was supplied by Henry Ford (1852-53), whose brief descriptive communication to the Academy of Natural Sciences of Philadelphia is said to have been accompanied by a fine skeleton of the ape. The first general treatise known to us in which the gorilla is described along with the other anthropoid apes is that of Gervais (1854). Under the names "Troglodytes, Gorille, Orang, and Gibbon" this author acceptably describes the structure, habits of life, and distribution of the four anthro- poid types. Both illustrations and text are valuable, but the work is of unusual inter- est because it presents what appear to be among the earliest definitely recognizable drawings of the gorilla. It was left to Isidore Geoffroy-Saint- Hilaire to assemble and present in con- veniently readable form the widely scat- tered facts concerning the history and characteristics of the gorilla. This he did in a conspicuously important monograph (1858-61). It is his distinction and merit also to have established the genus gorilla. It seems that the announcement by Sav- age and Wyman (1847) ^ new African ape deeply stirred scientific interest. As a result both the English and the French in- stituted search for specimens. In the course of a few years numerous skulls, a few com- plete skeletons, and several cadavers were obtained. A skeleton received in Paris in 1849 aJ^d the specimens which arrived in 1 85 1 commanded the immediate attention of the comparative anatomist de Blainville, whose work, interrupted by his death but continued by Duvernoy, was finally pub- lished by the latter in 1855-56. It is said that the two preserved specimens were ex- hibited at the International Exposition in Paris in 1852. According to Geoffroy-Saint- Hilaire, additional gorilla and chimpanzee materials arrived in Paris in 1853, 1854, and 1855, and as it is known that materials were received also in England, it is evident that the determined efforts to obtain speci- mens were reasonably successful. Although he at first accepted Owen's designation of the gorilla as Troglodytes savagei, Geoffroy-Saint-Hilaire later main- tained that the animal constitutes a dis- tinct genus and that the specific name might better be gina than savagei. He, therefore, called it Gorilla gina. In addition to its historical materials, the Saint-Hilaire monograph contains excellent accounts of habitat, habits, and general behavior. Following the discovery of the giant ape to science, and its establishment as a new genus of anthropoid, came its exploitation before the credulous public. For this the lay traveler and explorer Paul Du Chaillu was chiefly responsible. The publication of his Explorations and Adventures in Equa- torial Africa (1861) marks the dramatic climax of his efforts. Lacking knowledge of biology and adequate scientific training for the task he set himself, his statements and even his specimens from the first aroused the suspicion of scientific authori- ties. Du Chaillu's honesty has been ques- tioned, but whether or not fairly it is cer- tain that he was grossly careless in exposi- tion, and perhaps also in the handling of his gorilla exhibits. At any rate his publi- cations were so far repudiated by the sci- entific world that even today they are con- sidered first-rate examples of "nature fak- ing." Although the critics of Du Chaillu and his work are numerous and they have published several attacks and commen- taries, a single example. Gray (i86ic), will serve to indicate their point of view and mode of destructive attack. Gray, among other things, accuses Du Chaillu of tampering with his zoological specimens and of using both the statements and the drawings of others without proper acknowl- edgment. However charitable his inclina- tion, one must admit that the showingr for Du Chaillu is bad. With bare mention of the contributions to gorilla lore of Sanford (1862) and Reade (1863, 1864, 1868) we would con- clude this historical sketch. It would be THE EMERGENCE OF THE GORILLA 35 rash to assert that all of the existent spe- cies and varieties of anthropoid ape are known to science even today. As late as 1903 Matschie described a new species of gorilla, G. beringei, just discovered by the German colonial officer Captain von Be- ringe. The later years of the nineteenth century witnessed steady progress in anthropoid re- search. Of this, account will be taken in the later parts of this volume. Major prob- lems of classification were solved, essential facts of distribution and ecological rela- tions were gathered, the gross anatomy of each of the principal types of anthropoid ape was described with reasonable com- pleteness and adequacy, and the scientific world gained familiarity with living speci- mens of the great apes in supplementa- tion of its earlier acquaintance with skins, skeletons, and cadavers. Psychobiological studies even in the nineteenth century were few and of trivial importance. Conse- quently, except from naturalistic contribu- tions, little was learned about the behavior and mental traits of the anthropoids. We have achieved our main historical purpose of tracing the history of knowl- edge to the point of definite recognition of each of the anthropoid types, but before turning to our main interest, the behavior of the apes as made known to us through naturalistic observation and experimenta- tion, we must examine somewhat more systematically and critically than hereto- fore terminology, types, and relations. CHAPTER FIVE TERMS, TYPES, AND RELATIONS IN tracing the history of knowledge of the anthropoids we have found it nec- essary to refer frequently to important taxonomic and morphologic contributions. This is due to the interdependence of vari- ous lines of inquiry, their historical rela- tions, and their common or overlapping terminology. The order of appearance of notable varieties of interest in anthropoid research, as previously suggested, seems to have been crude natural history (appear- ance and manner of life), classification, anatomy, physiology, behavior, and psy- chology. The student of behavior need not be also systematist and morphologist, but to ignore these disciplines with their highly developed techniques and their invaluable assemblages of information would be in- excusable. It, therefore, seems desirable, in this our last historical and orientational chapter, to present briefly the derivation and meaning of certain recurrent popular and technical terms, and also certain essential informa- tion about anthropoid types and their ob- vious relations among themselves and to man. The term primates, already repeatedly used by us without definition or apology, is derived from the Latin primas, first or chief. It was used by Linnaeus for the "highest" order of the mammalia, which according to his view included men, mon- keys, lemurs, and bats (Homo, Simla, Le- mur, and Vespertilio). According to the strength and quality of one's pride, this association of man with monkeys and bats may strike him as oddly interesting, hu- morous, or belittling. As now defined, the order includes le- murs, monkeys, anthropoid apes, and men. The bats are omitted. There are two divi- sions, or suborders: the lemur-like animals (Lemuroidea), and the manlike animals (Anthropoidea), the monkeys, anthropoid apes, and man. Some authors recognize as a third suborder the Tarsioidea. Few of the millions who familiarly use the terms ape and monkey are capable of defining them precisely. Indeed, it is not an easy task. Because of its more remote origin we should inquire first about the his- tory and meaning of the word ape. It comes from the Old English, the masculine being apa, the feminine ape {Murray Diet.). Rennie (1838, p. 38) says of it: The word ape, which exists with little variation in all the modern European languages which have their origin in the ancient Teutonic, as aap in Dutch, a§e in German, apor in Swedish, &c., is commonly supposed to be derived from the Ger- man word a§en, to imitate (hterally to ape) ; and in English is apphed indiscriminately to all simiae without tails, which are, on that account, gen- erally considered to approach most nearly to the human form. In following the usage of the word ape through the centuries one finds many enter- taining reflections on the infrahuman pri- mates. "Visage after martyn apen: Folke heo buth, ful eovel y-schapen!" {K. Alts. 6464, A.D. 1300.) "An ape vvilbe an ape, by kinde as they say. Though that ye clad him all in purple array." (Puttenham, Eng. Poesie [Arabic] 211 Prouerbe, 1589.) Originally a generic term for manlike animal, ape later came to be restricted to such as lack tail and cheek pouches. Mur- ray says of it: "An animal of the monkey tribe {Simiadce) ; before the introduction of 'monkey' (i6th c), the generic name, and still (since 1700) sometimes so used poetically or rhetorically, or when their un- couth resemblance to men and mimicry of human action is the main idea. . . {Murray Diet., cf. ape.) Although the word continues to be used generically, the prevalent usage in America is for anthropoid ape. Since this meaning TERMS, TYPES, AND RELATIONS 37 seems to us for many reasons desirable, we have accepted it. The adjective anthropoid, from the Greek and meaning "of human form," was early used to restrict the applicability of ape. Related terms, such as anthropo- morpha and anthropomorphous (Linnaeus, 1735; Hoppius, 1760), appear in the litera- ture. A century since, the term was used as in this volume. "A race of Anthropoids, — neither Raleigh nor Sidney would have called them Men — has wormed itself into the dominion of the letter-press — not the literature of England." {Q. Rev., XLVIII [1832], 96.) The usages of the following quotation have existed for centuries and they con- tinue to be of interest and value. We say that an ape is a monkey without a tail, and a. haboon a monkey with a short tail, reserving the term monkey more particularly for those species which have very long tails; and though our early writers use these three words indiscriminately . . . yet the significations here given have generally prevailed since the time of Ray. . . . {Penny Cycl., II [1834], 144.) Baboon, a term of uncertain origin, ap- pearing in many ancient and modern lan- guages, has been consistently used to designate the dog-faced monkey, called also by the ancients Cynocephalus. Of the origin of the word monkey, which also has many spellings, we are ignorant. In one version of Reynard the Fox (1498) appears Moneke as the name of the son of Martin the ape. It is surmised that the term was brought to England by show- men from the Continent. Cognate terms are the French monne (sixteenth and seventeenth centuries), the Italian monna, and the Spanish and Portuguese mona. Often today, as was true in previous cen- turies, the word is used generically for all the infrahuman primates, and again it is applied more specifically. We favor, and have adopted, the usage which excludes, on the one hand, the lemur-like primates, and on the other, the manlike forms (an- thropoid apes), thus designating as mon- keys all other primates. The words simia and simian are so often used that they demand consideration. Ren- nie (1838, p. 35) is authority for the statement that they are generally thought to be derived from the Latin simus, mean- ing flat-nosed, though he admits that they may come from the Latin for mimic or simulator. Both meanings evidently are ap- propriate, since the primates are notorious imitators of one another and of man, as well as being flat-nosed. Lichtenstein (1791), whose account of the terms used by the ancients to designate the primates is excellent, states that the word simia was used in three senses by Latin writers: (i) As a general term for all apes and monkeys ; ( 2 ) for tailless apes, as distinguished from Cynocephali and Cercopitheci ; and (3), for the single genus called by Linnaeus Sylvanus, as distin- guished from Aegipan, Satyrus, and Sphinge. These different meanings, he re- marks, were not recognized by the writers themselves. Proceeding in this discussion from the general to the particular by way of such terms as primate, ape, and monkey, we come now to the names for those primates whose behavior is our subject matter. Gibbon, although alleged to be an Indian word, has not been discovered in any In- dian language {Murray Diet.). Buffon, whose scientific writings are the earliest in which we have discovered the term, states: Gibbon is the name by which M. Dupleix sent us this animal from the East-Indies. I thought at first that this was an Indian word, but in looking over the nomenclatura of the monkey tribe, I found a note of Dalechamp's upon Pliny, that Strabo has described the cephos by the word Keipon, from which, probably, Guibon, Gibbon, is derived. (Barr's Buffon, 1797, IX, 185, foot- note.) Rennie's account of the term is similar to and confirmatory of that of Buffon. The history of our knowledge of the gibbons, and other true apes, ascends to a more remote period of antiquity than has been hitherto sus- pected. The name gibbon, indeed, though of an- cient origin, is modern in its apphcation to the animals which now bear it; since we learn from Aristotle that the k^/3os, /c^ttos, Keiiros, or cephiis, of the ancient Greeks and Romans, (a word itself 38 A STUDY OF ANTHROPOID LIFE Fig. 25. Drawing of orang-outan heads. Adult (left), child (right). From Hermes, 1876. Fig. 26. Drawing of orang-outan heads. Adult (right), child (left). From Hermes, 1876. clearly derived from the Hebrew '"j^p, koph,) had a long tail; but though it may have been origi- nally misapplied to the hylobates, custom has so sanctioned its use, that it would now be difficult, even were it desirable, to change it. (Rennie, 1838, p. 146.) Whatever its origin, gibbon is the com- mon term for that family of apes which the taxonomist Illiger (1811) designated as Hylobates, a term which is truly de- scriptive, since it means tree-walkers. Both gibbon and Hylobates would be entirely satisfactory in their appHcation were it not that some systematists have established two genera of gibbon, one of which they have called Hylobates, the other Sympha- langus. This complication we shall consider later under types. Orang-outan is an adaptation of two Malay words, orang meaning a reasonable being, and outan, of the woods or wild. It TERMS, TYPES, AND RELATIONS 39 is variously spelled, but Rennie (1838, p. 81) states as the correct form in English orang-outan. The first to record the name in scientific literature, as applied to the East Indian ape, is thought to be Bontius (1658). Systematists unfortunately have attached many names to the creature com- monly known as orang-outan. Among them are Simla, Pithecus, Papio, Pongo. Had they consistently used the common name, endless confusion would have been avoided. As one reads the literature he comes to feel that too many authorities, each with the conviction that he may do as he likes about nomenclature, are worse than none. Chimpanzee is thought to be derived from a native African word. It appears in several different spellings. The first which we have found is Quimpeze (de la Brosse, 1738). Matthews (1788) gives as alterna- tives Japanzee and Chimpanzee. That the word as now spelled, and with its present application to the smaller of the two Afri- can anthropoid apes, has been in use for approximately two centuries is indicated also by the following statement: A most surprizing creature is brought over in the Speaker, just arrived from Carolina, that was taken in a wood at Guinea. She is the Female of the Creature which the Angolans call Chimpanze, or the Mockman. (Lond. Mag., September, 1738, P- 465-) Even less fortunate than the orang- outan in its adventures with zoological names is the chimpanzee, for at various times and by diverse authorities it has been called Homo, Orang-outang, Pongo, Simla, Pithecus, Troglodytes, Pan, and by trav- elers or explorers Barys or Barris, Smitten, and yet other odd names. Supposedly an African name for wild and hair)^ men, gorilla appears first in the account of Hanno's exploratory voyage, al- ready quoted on page 3. Martin (1841, p. 372) tells us that the word gorilloi used by the translator of the Hanno record may be identical with Drill and Mandrill which are old African names still in certain places used for the chimpanzee. By Savage and Wyman (1847) gorilla was selected as specific name for the new type of African ape which they mistakenly described as a species of chimpanzee. Sub- sequently it naturally became the name of the new anthropoid genus. Reliable records seem to indicate that confusion of native African words and their adaptations is partially responsible for delay in the scientific identification of the chimpanzee as distinct from the Asi- atic orang-outan, as well as in the discov- ery of the gorilla. Engeco, as used by Bat- tell (Purchas, 1625); Inchego (Bowdich, 1 8 19); Enche-eco (Savage and Wyman, 1847), and its corruption, Jocko, except as misapplied by Buffon (1789), Aude- bert (1800), and a few other authors, to the eastern orang-outan, certainly desig- nate the chimpanzee. Likewise, Battell's term Pongo, presumably derived from the native tribal name Mpongwe; Ingena, as used by Bowdich; Enge-ena of Savage and Wyman, and its corruption, Gina, unmis- takably apply to the gorilla. This hasty and incomplete examination of the history and meanings of terms which we shall many times use naturally leads to the principal problems of classification, nomenclature, and historical phases of their solution. It is no part of our task to out- line the history of these problems, or to in- dicate in detail their present status. In- stead it will suffice for our present need to illustrate stages of progress in the classifi- cation of the primates and to describe somewhat more fully the particular classifi- cation which we have selected for use. For discussion of classification and no- menclature among the ancients we can cite no better authority than Lichtenstein (1791). With him we leave consideration of the prescientific period and pass to the contribution of Linnaeus. In the first edi- tion of the famous Systema naturae (1735), Linnaeus applied the term Anthro- pomorpha to a group of animals consisting of men, monkeys, and sloths {Homo, Simia, Brady pus). In the tenth edition, 1758, Anthropomorpha is replaced by Primates, which includes four genera: men, monkeys, 40 A STUDY OF ANTHROPOID LIFE lemurs, and bats. Even at that time many types or species of "Simia" were distin- guished and with varying degrees of preci- sion and adequacy described. Cuvier, who was comparative anatomist and paleontologist, as well as taxonomist, in his Legons d'anatomie comparee (1800) groups what we today know as primates in two families: I. Les Bimanes (two-handed), II. Les Quadrumanes (four-handed). The first family includes man alone. The sec- ond includes the monkeys (Simla) and the lemurs, as indicated in the following schema (see Gregory, 19 10, p. 65). Family I. Les Bimanes I"; Homme Homo) Family II. Les Quadrumanes Singes (Simia) Makis (Lemur) Homo Pithecus Callithrix Cercopithecus Cynocephalus Papio Cebus Lemur Indris Loris Galago Tarsius The classification of Cuvier has been selected to indicate the status of primate taxonomy at the beginning of the nine- teenth century. Similarly, that of Forbes, as given in his Handbook to the Primates (1894), may represent the end of the cen- tury. The Order PRIMATES, therefore, comprises two very homogeneous sub-orders — (i) The Le- mur-like animals (LEMUROIDEA) including the Aye-Aye, the Tarsier, and the True Lemurs; and (2) the Man-Hke animals (the ANTHRO- POIDEA), which embrace the Marmosets, the Baboons, the great Apes, and Man. (Forbes, I, 3.) Commenting on the taxonomic relations of man, Forbes writes: Notwithstanding the numerous varieties and races of mankind distributed over every region of the globe, each exhibiting differences in habits, customs and superficial complexion, Man forms but one species. Homo sapiens, the sole repre- sentative of the unique genus of his family. (I, 1-2.) Order Primates Suborder I. Lemuroidea Tarsiers, Lorises, Lemurs Suborder II. Anthropoidea Family i. Hapalidae Family 2. Cebidae Family 3. Cercopithecidae Family 4. Simiidae Family 5. Hominidai Forbes's classification of the Simiidae or, in our terminology, anthropoid apes, fol- lows : I. HYLOBATES, Illiger 1. agilis, F. Cuvier 2. leuciscus (Schreber) a. leuciscus (Schreber) b. concolor, Schlegel 3. leucogenys, Ogilby 4. lar (L.) 5. hoolock, Harlan 6. hainanus, Thomas 7. syndactylus (Desmarest) II. SIMIA, L. I. satyrus, L. III. GORILLA, Is. Geoffr. I. gorilla (Wyman) Family Simiidae IV. ANTHROPOPITHECUS, de Blainville 1. troglodytes (L.) 2. calvus (Du Chaillu) Including all of the gibbons in the genus Hylobates, Forbes describes seven species/ of which one presents two subspecies. For the genus Simia (orang-outan) he gives but one species. Likewise for the genus Gorilla^ only one species is described. In the genus Anthropopithecus (chimpanzee) two species are recognized. In the decade between the publication of Forbes's handbook and the appearance of Max Weber's important volume on the mammalia {Die Sdugetiere, 1904), com- parative anatomy as basis for taxonomy progressed rapidly. Weber presents in mas- terly fashion an impressive assemblage of morphological facts, and in the light thereof a classification of the primates which in several respects differs radically from its predecessors. For example, the group primates is resolved into two orders, the Prosimiae and the Simiae. The latter in TERMS, TYPES, AND RELATIONS 41 WEBER'S CLASSIFICATION OF THE PRIMATES Order Suborder Prosimi£e Family I. Tarsiidae II. Lemuridae Genus Primates ^ Simiae I. Platyrrhina 1. Hapalidce 2. Cebidas II. Catarrhina 1. Cercopithecidae 2. Hylobatidae 3. Anthropomorphce . Genus Simia Linnaeus (orang-outan) S. satyrus Linnaeus S. abeli Clarke Genus Gorilla G. gorilla Wyman Genus Anthropopithecus de Blainville A. troglodytes Linnaeus A. calvus Du Chaillu A. {Troglodytes) tschego turn is divided into the suborders Platyr- rhina (monkeys with nostrils opening out- ward and separated by a broad septum) and Catarrhina (monkeys and apes with nostrils opening downward and separated by a narrow septum). Instead of grouping all of the anthropoid apes in a single family, as does Forbes, Weber constitutes the gibbons a separate family called Hylobatidae, consisting of two groups, the gibbons and the siamangs, in a single genus. The remaining anthro- poid apes he groups in the family Anthro- pomorphae, as is indicated in the above schema. Weber's classification has the conspicu- ous merit of recognizing the striking mor- phological differences of the lemur-like ani- mals, which he calls Prosimiae, from the true monkeys and apes, or Simiae; and likewise, the morphological gap between the gibbons and the three types of great ape. Although in several of the points above mentioned we consider his classifica- tion more satisfactory than that of Elliot (1913), we wish to present the latter be- cause Elliot's Review of the Primates is an exceedingly useful assemblage of informa- tion to which we shall have occasion fre- quently to refer throughout this volume. All of the classifications, as here pre- sented, are incomplete; species ordinarily have been omitted, and, for all groups ex- cept the anthropoid apes, genera and in some instances even families. In view of the extreme confusion of an- thropoid types which has long obtained and persists even to this day, it would seem desirable to use consistently as generic terms, gibbon, orang-outan, chimpanzee, and gorilla, in preference to any of the taxonomic designations which have been proposed. Except, therefore, as we quote other authors or refer to specific classifica- tions, we shall feel free throughout this work to use these familiar terms to desig- nate types and shall ordinarily indicate ELLIOT'S CLASSIFICATION OF THE PRIMATES Order f Suborder I. Lemuroidea Primates | Suborder II. Anthropoidea Family I. Family II. Family III. Family IV. Genus I. Genus II. Family V. Genus I Genus II Genus III Genus IV Family VI. Callitrichidae Cebidse Lasiopygidae Hylobatidae Hylobates — Gibbons Symphalangus — Gib- bons Pongiidae Pongo — Ourang-utan Gorilla — Gorilla . Pseudogorilla — May- ema Ape Pan — Chimpanzees Homonidae 42 A STUDY OF ANTHROPOID LIFE species or variety by prefixing or suffixing some generally known and widely accepted descriptive term. For example, we shall use Bornean orang instead of Pongo pygmaeus, Simia pygmacus, or Simia satyrus ; and Sumatran orang instead of Pongo pyg- maeus abelii, Simia abelii, or Simia bicolor. Likewise, we may refer to the bald- headed chimpanzee or Chimpanzee calvus instead of Pan calvus, Simia calvus, An- tkropopithecus calvus, or Mimetes troglo- dytes. The species koola-kamba we shall commonly designate as chimpanzee koola- kamba or simply koola-kamba, instead of by the Latin names Pan koola-kamba, Trog- lodytes koola-kamba, or Simia koola- kamba. Since for the genus Gorilla, heaven be praised, the taxonomists have not created a multitude of names, we may safely use it in company with suitable specific term, or we may prefix a well-chosen descriptive term. Thus the most recently discovered gorilla type may be unequivocally desig- nated as mountain gorilla or Gorilla be- ringei. Mountain is appropriate because of the nature of the animal's habitat; beringei, because it recognizes the discoverer, Cap- tain von Beringe. Division of the Hylobatidae into two genera, the Hylobates, the gibbons com- monly so-called, and the Symphalangus, popularly known as siamangs, creates a difficulty, for no longer can the word gib- bon safely be used generically as can orang, chimpanzee, and gorilla. For the present, however, it appears to us desirable to con- tinue it as synonymous with Hylobatidae and thus inclusive of the siamang. Ordi- narily, however, we shall apply the term siamang as well as a specific term to avoid possible confusion of this genus with Hy- lobates. Such popular terms as white- handed gibbon, instead of Hylobates lar, agile gibbon instead of Hylobates agilis, or hoolock instead of Hylobates hoolock, we shall feel entirely free to use. Because behavior may vary with type (genus, species, variety) as with individu- ality, sex, stage of development, and physiological condition of the organism, it is essential that an animal which serves as object of studv be so carefully and accu- Fig. 27. White-cheeked gibbon, Hylobates leucogefiys. i From Sclater, 1877a, Proc. Z06I. Soc. London. . rately described that it may be classified tl and safely compared with other indi- I viduals in the several respects mentioned, f This necessity is the ground for the lively i interest of students of behavior and psy- chobiologists in taxonomic method, discov- k eries, and nomenclature. As one step in iDj what we conceive to be a profitable direc- t tion, we would now offer a general survey «tf of the major divisions of the anthropoid d apes, for, as we have already had reason m to remark, definite and adequate descrip- (ai TERMS, TYPES, tion of an animal subject depends pri- marily on wisely selected and well-estab- lished principles of classification. To pro- ceed, then, with our survey. The gibbons clearly enough fall into two groups, recognized as genera by certain au- thorities. They are, as previously stated, the Hylobates, or true gibbons, and the sia- mangs. The former genus, called Hylobates by Elliot, includes some twelve species or varieties which differ chiefly in color mark- ings, and are in such respect extremely variable., To include the siamangs, the genus Symphalangus has been established. In it there are three species or subspecies: S. syndactylus (formerly known as Hyloba- tes syndactylus, Simia syndactylus, Sia- manga syndactyla, and the Siamang gib- bon), S. s. continentis, and S. klossi. The latter is said by Elliot to be a very small form of siamang, differing from the first species only in size. The Hylobates and Siamangs differ chiefly in that the latter have a laryngeal sac which in Hylobates is lacking, are in general somewhat larger than Hylobates, and possess more pronounced supra-orbital ridges. As one reads the taxonomic account of the Hylobatidae one wonders whether spe- cies-making has not been overdone and whether perhaps the great variation in color markings has misled observers. Authorities are agreed that there is only one existent genus of orang-outan, and although for many years it has been sus- pected that there are two species, the one found in Borneo and the other in Sumatra, the fact is not perfectly established. By Elliot (19 13) the Bornean orang is called Pongo wurmbi, and the Sumatran form P. abelii. In the genus Chimpanzee, ten species have been described. By Elliot the follow- ing are listed. We shall take the liberty of using Chimpanzee as our generic term in- stead of Pan, which is Elliot's term. C. calvus (bald-headed chimpanzee), C. juUgi- nosus, C. satyrus, C. kooloo-kamba, C. leu- coprymnus, C. chimp anse, C. sckweinfurthi, ND RELATIONS 43 C. aubryi, C. vellerosus, and C. juscus. Although some of these species are well established, it is extremely difficult to iden- tify and classify immature specimens. Con- sequently, students of behavior often find it next to impossible to designate the spe- cies of chimpanzee observed, or even to de- scribe individuals in sufficient detail to en- able the experienced systematist to do so. The gorilla, like the orang-outan, seem- ingly varies markedly only in separated and differing habitats. There are two readily distinguishable forms: the lowland type. Gorilla gorilla, with a few subspecies or varieties, and the mountain type, Gorilla beringei. The difficulties which the student of behavior meets in his attempts to classify or describe the chimpanzee are absent in the case of the gorilla. But as between the two genera a new uncertainty arises, for there are evidences of the occurrence of intermediate forms. Several such indi- viduals are mentioned in the anthropoid literature. Sometimes they are described as chimpanzees; sometimes, as gorillas. Elliot has set up the genus Pseudogorilla, with the single species, mayema. This rarely encountered intermediate form may be a hybrid between the gorilla and chimpanzee. We have attempted to offer taxonomic orientation for students of anthropoid be- havior and to recommend certain authori- ties and specific classifications which we believe may be relied upon and advantage- ously used. Similarly, we would now men- tion and recommend general morphological authorities and sources for those whose special psychobiological interests and in- quiries may necessitate reasonably com- plete and detailed knowledge of the struc- ture of anthropoid apes. For general accounts of types, natural history, and structure, we would suggest Rennie (1838), Martin (1841), Vrolik (1841), Duvernoy (1855-56), Hartmann (1885), Keith (1896), Huxley (1863), and Heck (1922). The most convenient recent single source of morphological de- scription is The Morphology and Evolution of the Apes and Man (1924) by Sonntag. 44 A STUDY OF ANTHROPOID LIFE This work, although barely more than a syllabus, has many advantages for the stu- dent of behavior. Among them is the pres- entation of a list of more than five hundred references, chiefly to accounts of structure. Of all the anthropoid apes the gibbons are least like man, structurally and in be- havior. Next, in order of increasing resem- blance, comes the orang-outan, while the chimpanzee and gorilla compete for first place. In some respects the one, and in some the other, is the more like man. In order of lessening structural fitness for ar- boreal life, the anthropoid types rank: gib- bon, orang-outan, chimpanzee, gorilla. As between the orang and chimpanzee there is not much to choose, but there is a vast difference between gibbon and gorilla. Even the superficial observer notes indications of family relationship between gorilla and chimpanzee, whereas the gibbons seem much more remotely related to the other anthropoid apes and to man. As we may not offer even a general ac- count of the status of knowledge of the genetic relations of anthropoid types, we must again have recourse to the citation of authorities. There is no dearth of interest- ing and useful discussions of the subject, but there is complete lack of definite infor- mation. Together with many ingenious theories and much speculation, we find precious fragments of information in al- most all divisions of biological science. Presently we may reasonably expect these fragments to fit together into a consistent and intelligible whole which will enable us to read accurately the genetic history of anthropoid types and of man. Morphological facts indicate that al- though the anthropoid apes are more like man than are any other animals, and that their order of increasing resemblance is gib- bon, orang, chimpanzee, and gorilla, there is little likelihood of human origin or de- scent from any one of the existing types. Instead all are believed to have developed from a common ancestral form which is now extinct. As facts of behavior and of psychobio- logical status may presently throw new and important light on the chief problems of primate relationships and human origins, and as in such case it will be desirable for us to have clearly in mind theories of de- scent and ancestral schemata which have been inspired primarily by consideration of morphological facts, we venture to present, with proper acknowledgments to the au- thor, and as an example, the tentative scheme of relationships within the order primates constructed by G. Elliot Smith. Fig. 28. Hypothetical relationships of the primates. From G. Elliot Smith, 1924. Courtesy of Oxford University Press. We have discussed terms, types, and re- lations as preparation for examination of the facts of anthropoid behavior, and to aid us in understanding, evaluating, and using them. We shall now enter upon our main task, the critical examination of available records of anthropoid life in order to con- struct therefrom safe and as nearly as may be accurate description of the life history and action-systems of the several types of anthropoid ape. PART II GIBBON c e I) 0 e a I I ( i t GIBBON CHAPTER SIX THE HABITS AND LIFE HISTORY OF GIBBON WITH a classification dictated by what we conceive to be psycho- biological interests, we have ar- ranged the data of gibbon behavior in three chapters. In the first are presented the essential and fairly well-established facts of natural history, including distribution, habitat, habits, and life history; in the sec- ond, a description of emotional life and expressions in the gibbon; and in the third, an account of receptivity and adaptivity. In thus segregating our naturalistic mate- rials and arranging them in psychobiologi- cal categories, we have, it is true, departed from the time-honored practice of systema- tists, naturalists, and general zoologists. We hope that the method of presentation may prove convenient as well as logical and especially that it may serve to reveal and emphasize the gaps in our knowledge, unsolved problems which should be at- tacked, and opportunities and needs for naturalistic and experimental inquiry. Throughout the chapters we have added to what we found in the literature on gibbons our own observations, often unrecorded, and other pertinent data which in various ways we have been able to assemble. Con- sequently our description, although pri- marily historical, is also in a measure original and calculated to advance knowl- edge rather than merely to indicate its present status. HISTORICAL SUMMARY Although acquaintance with the gibbon may be traced back some twenty-five cen- turies, scientific knowledge is both young and immature. A resume of the statements scattered through our previous chapters may be serviceable. Whereas the comments of Aristotle do not convince us that gibbons were known in his time, the evidences in Pliny and Galen are more varied, positive, and use- ful. Indeed, we feel reasonably assured that Pliny wrote of the gibbon and that Galen dissected it. Marco Polo's reference, in the thirteenth century, to manlike animals is chronologically next in order. Then follow the historical accounts of Gesner (1551) and Aldrovandi (1637). They effectively perpetuated but added nothing to the knowledge of the ancients. The description offered by Le Comte (1697) unmistakably applies to the gibbon. But perhaps the birth of scientific description should be dated from the publication in 1766 of the fourteenth volume of Buffon's Natural His- tory rather than from the writing of Le Comte. Shortly after the publication of Buffon's famous volume appeared de Visme's (1769) illustrated account of the gibbon. The references of Turpin (1771) and Charles Miller (1778) are unimportant, but van Iperen and Schouman in 1784 supplied a really useful description of the wau-wau, and Audebert (1800) presented the excellent illustrations which we repro- duce as figures 20 and 21, p. 28. Early in the nineteenth century interest in the gibbon family appears to have in- creased, and there were published several scientific contributions, including those of Raffles (1822), E. Geoffroy-Saint-Hilaire and F. Cuvier (1824), and Horsfield (1824). As in the previous part of this volume we have endeavored to survey the presci- entific period of anthropoid inquiry, in the present part we shall feel free to devote our 48 A STUDY OF ANTHROPOID LIFE attention j)rimarily to the content of sci- entific contributions and to endeavor to give a connected account of the informa- tion which has become available. More illuminating than much that has since been written is Le Comte's descrip- tion of ''a species of ape." It is an admi- rable introduction to gibbon behavior. For myself, in passing from China to the coast of Coromandel, I saw in the Strait of Malacca a species of ape. . . . This animal walked naturally on its two hind legs, which it bent ever so little, like a dog that has been taught to dance. It made use of its two arms as we do ; its face was fashioned almost ex- actly like those of the savages at the Cape of Good Hope ; but its whole body was covered with white, black, or gray wool : nevertheless its cry was exactly like that of a child; all of its external behavior was so human and its passions so lively and striking that even dumb men could have ex- pressed their sentiments and wishes little better. They seemed to be above all of a very tender dis- position, and to show their affection toward those whom they knew and loved, they embraced and kissed them with surprising transports. They have an action which is not found in any other ani- mal, and which is characteristic of children; that is, to stamp with joy or with displeasure, when they are given or refused something for which they have a passionate longing. Although they are very large (for those I saw were at least four feet high) their nimbleness and adroitness are incredible. It is a pleasure beyond expression to see them run up the tackling of a ship, where they sometimes play, as if they were especially made for the art of vaulting; or as if they had been paid, like our rope-dancers, to amuse the company. Sometimes suspended by one arm, they balance themselves for some time nonchalantly to try themselves, and then turn, all of a sudden, around a rope, with the rapidity of a wheel, or a sling that is put in motion; sometimes 'holding the rope successively with their long fingers, and letting themselves drop into the air, they run with full speed from one to the other, and return with the same speed. There is no posture they cannot imi- tate, nor any motion they cannot perform; bend- ing themselves like a bow, rolling like a bowl, hanging by their hands, feet, and teeth, according to the different fancies with which their bizarre imagination furnishes them, and which they per- form in the most diverting manner in the world : but their ability to fling themselves from one rope to another, at a distance of thirty or forty feet, seems still more surprising. (Le Comte, 1697, II, 362-364.) A full century later there appeared in Latreille's Buffon (1799-1808, XXXV, 140) another typical naturalistic account of the gibbon. We quote it from Harlan's translation. "This Orang-outang, named Voulock [Hoolock] in its native country, was a female, and regularly menstruated, but the discharge was interrupted after the attack of scurvy. She was of a very gentle disposition, only monkeys displeased her, whose presence she could not endure. She always walked in the upright attitude, and could even run very fast : when walking on a table, or among china-ware, she was very careful not to break any thing; when climbing she used only her hands; her knees resembled those of man. Her cry was sharp and deafening, pronouncing often and fre- quently repeating the syllables yaa-hoo ! yaa-hoo ! yaa-hoo ! — with the emphasis on the last syllable, particularly on the terminal sound : when she heard any noise resembling this, she commenced crying also. When contented, she emitted a low guttural sound. When sick she whined like a child, and was fond of being nursed. Her food consisted principally of vegetables and milk; she would never touch a dead animal, or eat meat, and re- fused even to eat from a plate which had con- tained meat" [in this respect she differed from those individuals in the possession of Dr Bur- rough, these latter would eat meat occasionally]. "When thirsty, she plunged her fingers into the water and licked them : she voluntarily covered herself with pieces of sail-cloth, but would not endure clothes. She would come when called by name. She was commonly melancholy and pen- sive." (Harlan, 1834, p. 53.) Keith, who in 1896 prepared a sum- mary digest of the scientific literature on the gibbon, deplored the paucity of data on this family of anthropoid apes and re- marked that it is not due to lack of op- portunity for study, since in recent years there have been thirty-five specimens be- longing to different species of gibbon in the Zoological Gardens of London. Our knowledge of its anatomy is based upon a very small amount of material. Until five years ago, when Kohlbriigge pubhshed dissections of four specimens, our information was confined to incomplete descriptions of the anatomy of five animals. . . . After their arrival in Europe, they are soon at the disposal of the dissector, for un- fortunately they do not live long in confinement, few of them more than a year. Of three gibbons that were in the Rotterdam gardens, two lived for about a month, the other died after a sojourn of eight days. (Keith, 1896, p. 372.) THE HABITS AND LII If the systematists and morphologists may reasonably complain of meager infor- mation concerning gibbons, much more so may the psychobiologist, for whereas there are now several excellent anatomical publi- cations on this family of apes, there are only a few first-rate naturalistic descrip- tions and only two experimental studies of behavior which are worthy of attention. One marvels at the fact and wonders why no enterprising biologist has intensively studied the natural history of the gibbon. Although not an easy task it should be al- luring, because of the characteristics of the animal itself and the historical failures. STRUCTURAL CHARACTERS Smallest of the anthropoid apes, and in many aspects of structure as well as be- havior least manlike, the gibbons are dis- tinguished from the other anthropoids by the presence of small ischial callosities, shape of skull and facial contour, color and texture of skin and hair, relative length of arms, degree of arborealness, and posture in climbing, walking, and resting. In height, the full-grown gibbon, with the exception of the siamang which is con- siderably larger, seldom exceeds three feet. The animals are very slender, with chest well developed, but abdomen constricted and likened by some authorities to that of the greyhound. The latter contrasts almost ludicrously with that of the gorilla which is extremely large. The weight of the crea- tures, rarely given by observers, is surpris- ingly slight. Hornaday supplies the follow- ing measurements for "the largest speci- men I measured in Borneo": head and body, 19 inches; extent of outstretched arms and hands, 5 feet i inch; entire reach of arms and legs, 5 feet i inch; hand^ 6>4 inches long by i inch wide; weight, l^o^ pounds (Hornaday, 1904, p. 12); ^nd Keith (1895, p. 292) gives the body weight of the gibbon as about 12 pounds, and for the siamang about 2 1 pounds. The lay observer is always struck by the great length of arm in the gibbon. Accord- ing to Huxley (1863, pp. 23-24) the pro- HISTORY OF GIBBON 49 portion of arm length to leg length is ex- ceeded only by the orang-outan, while the proportion of arm length to body length is greater in the gibbon than in any other an- thropoid ape. So long are the arms that as the animal walks upright the fingers in some cases nearly touch the ground. The hand is very long and narrow, exceeding the foot in length. Both the thumb and the great toe are widely separated from the next digit. The great toe is well developed and may be nearly half as long as the foot. In the siamang, regularly, and occasion- ally in other members of the gibbon family, the second and third toes are connected with a web or fused completely. The head is variously described as round- ish or egg-shaped. The latter term seems to us more strictly applicable. The face by many observers has been characterized as more like the human, for the nose is more prominent than is the case in any other ape, and the nostrils, opening downward and outward, increase the similarity to man. The teeth are said to appear slowly and relatively late in the period of devel- opment. We have failed to find entirely satisfactory authority for this statement and the observational data are far from adequate. The canine teeth are large. Of all the anthropoid apes the true gib- bon alone, and here the siamang is again an exception, lacks that peculiar structure which is called laryngeal sac. In the sia- mang the structure is conspicuously pres- ent and functions apparently in connection with vocalization. The skin ordinarily is black and carries a coat of hair which is characteristically thick, deep, and woolly in the gibbons proper. Its color ranges from black, through brown, straw-colored, and gray, to snow- white. In some members of the family, the hands, feet, face, and breast are naked; and in the siamang the skin covering the laryngeal sac, as well as that of the face, hands, and feet, is relatively free of hair. The brain of the gibbon differs less in shape, size, and proportions from that of the monkeys than do those of other an- 50 A STUDY OF ANTHROPOID LIFE thropoid apes. The surface is said to be less rich in convolutions and sulci and the frontal lobes to be more flattened. It is said Fig. 29. biamang, with laryngeal sac inflated. Courtesy of F. W. Bond, photographer, and Zoological Society of Lon- don. also that the occipital lobes of the cerebrum are smaller than in the other anthropoids. For supplementation of this brief struc- tural description we would refer the reader to Sonntag (1924) and to morphological authorities mentioned in his extensive bibli- ography. Because the siamang differs so strikingly from the other gibbons it is desirable to characterize it separately. It is both taller and heavier than the gibbon proper, with jet-black skin and hair, the latter being coarser and rougher than in Hylobates. The skin of the throat is bare and disten- sible over the large laryngeal sac. The sec- ond and middle toes are united as far as the last joint. The skull is larger and the supra-orbital ridges more highly developed than in gibbons. The arms are, relatively, shorter. Forbes (1894, II, 167) states that the frontal lobes of the brain are flat, and that the olfactory bulbs extend forward be- yond them. The occipital lobes are small, and the cerebellum projects from beneath the cerebrum. But among all these struc- tural peculiarities, the outstanding charac- teristic of the siamang, the one by which it may most easily be distinguished from other members of the large family, is the naked skin covering the laryngeal sac. When this is distended in the use of the sac the appearance of the animal is ex- traordinarily distinctive. DISTRIBUTION, HABITAT, AND SPECIES The gibbon family is strictly oriental and inhabits the Indian zoogeographical re- gion. Its distribution is of particular inter- est in relation to species formation and modification. By one or another species it is represented in southern China, the Malay Peninsula, the Malay Archipelago, and the Island of Hainan. In the latest edition of Brehm's Tierle- Fig. 30. Siamang, with laryngeal sac partially inflated. Courtesy of New York. Zoological Society, E. R. Sanborn, photographer. ben (1922), Heck^ recognizes as estab- lished and worthy of naturalistic descrip- 1 In the fourth edition of Brehm's Tierleben, L. Heck is responsible for the section on Pri- mates. THE HABITS AND LIFE tion four species of Hylobates: H. hoolock, H. lar, H. agilis, and H. leuciscus, in addi- tion to the genus Siamanga. Writing some- what more recently (1924, pp. 73-74), and with quite different purpose, Sonntag recog- nizes the siamang and eight species of Hy- lobates: H. hainanus, H. lar, H. agilis, H. pileatus, H. muelleri, H. leuciscus, H. hoo- lock, and U. leucogenys. Of the twelve spe- cies described by Elliot (19 13) three or four are decidedly questionable. As distribution, habitat, and behavior differ significantly for the various species, it is necessary at this point to list them under the common names which we have adopted for use in this volume and to pre- sent certain essential information concern- ing each. Because of the multiplicity of species names and the persistence of con- fusion of types it is necessary also to pre- sent the more important recent synonyms. 1. Agile gibbon = Hylobates agilis F. Cuvier = H. lar — H. variegatus = H. rafflesti — H. unko = H. pileatus = Slen- der gibbon = Active gibbon. Found exclu- sively in Sumatra and Siam (Forbes, 1894, II, 153), or in Sumatra alone (Elliot, 19 13, III, 169; Martin, 1841, p. 425). The agile gibbon varies markedly in coloration and in consequence has been the subject of much discussion and the cause of confusion. 2. Bornean gibbon = Hylobates con- color Harlan = H. harlani = H. miilleri — H. junereus = Miiller's gibbon. Found in Borneo. This species also is subject to j color variations which are imperfectly ' known and still less understood. 3. Hainan gibbon = Hylobates nasutus Klinckel = H. pileatus — H. hainanus. Found in the Island of Hainan and Cochin I China (Elliot, 1913, III, 155). 4. Hoolock = Hylobates hoolock Har- lan = H. hulok — H. choromandus — H. niger. Found in the Malay Peninsula (?) , (Upper Assam, Aracan, Yunnan). i 5. Siamese gibbon = Hylobates pileatus I Gray = H. agilis. Found, according to I Elliot (1913, III, 170), in Cambodgia; Paknam Kabin, Siam; Cochin China. HISTORY OF GIBBON 51 6. Wau-wau = Hylobates leuciscus Geoffroy = H. javanicus = Silver, silvery, or gray gibbon. Found in Java. 7. White-cheeked gibbon = Hylobates leucogenys Ogilby. Found in Siam. Fig. 31. Female siamang, abuut fivt- yL-ai> uld. Courtesy of New York. Zoological Society, E. R. Sanborn, photogra- pher. 8. White-handed gibbon — Hylobates lar Linnaeus = H. variegatus — H. albi- manus = H. unko = H. leuciscus = H. entelloides = H. agilis. Found in India: Tenasserim, Malay Peninsula. Siamang = Symphalangus syndactylus = Hylobates syndactylus — Siamanga syndactyla. Found in Sumatra and possibly also in the Malay Peninsula (Elliot, 1913, III, 177). All of the species of Hylobates are found in upland forests at elevations rang- ing, according to different observers and for the different species, from four or five hundred to five thousand feet above sea level. Our primary authorities for this statement are Tickell (1865), Anderson (1878), and Blanford (1889-91). The sia- mangs alone frequent sea level and the coast. Heck (1922, p. 614), on the au- thority of one Wray, states that the true gibbons avoid altitudes greater than four thousand feet and correspondingly cold re- 52 A STUDY OF ANTHROPOID LIFE gions, while a species of siamang ascends as high as seven thousand feet in the moun- tains of the Malay Peninsula. Its coat, pre- sumably adapted to the high altitude tem- peratures, is described as long and rough. The description suggests that this type of siamang is comparable in its environmen- tal relations and adaptations to the moun- tain species of gorilla and that both are high altitude types. By one authority the reader is assured that gibbons are much alike in all essen- tials, and by another that they differ im- portantly. Perhaps the contradiction is due in large part to the now well-recognized variations in coloration and color pattern in both genus and species. From the data we have succeeded in assembling it is clear that color varies with species, individual, sex, developmental stage, and perhaps also climatic and nutritional conditions. Prob- ably the facts would be difficult enough to understand if completely observed even in a single well-defined species. It is no won- der, then, that the systematists have been puzzled by the extreme differences in the coloration of specimens from the same geo- graphical region and presumably repre- senting the same species. Forbes, writing in 1894, describes the coloration of the several species of Hy- lobates with simplicity and definiteness. Elliot in 19 1 3 offers more elaborate de- scriptions and is much less certain of the adequacy of his knowledge. The siamangs and several types of gibbon at one time or another in their life history are jet-black. The wau-wau is typically ashy gray in coat color, and in certain other species there is a considerable range of color, combined with a complex and variable pattern. Gradually naturalists and systematists have come to appreciate the risk of basing species on coat characters; but we are still, it appears from the literature, far from an intelligent understanding of the facts, rela- tions, and causes of coat color and pattern in these highly interesting apes. Relations of coloration to sex and age are well established. Pocock (1905, p. 172) is authority for the statement that an adolescent female Hainan gibbon which when first observed was dark smoky gray, shortly after arrival at the London Zoo- logical Gardens became light gray. The change apparently coincided with sexual maturity. Swinhoe (1870, p. 224) states that in this species the males are black and the females white. ' Of the hoolock, Sanyal (1907, p. 277) writes that: The species may be divided into the four fol- lowing groups: (1) Light-coloured female hoolocks turning grey, or even white with age. (2) Black, or grey-coloured female hoolocks, becoming lighter grey or white with age. (3) Black female hoolocks never turning grey or white. (4) Light-coloured, or grey males, remaining always the same colour. THE HABITS AND LIFE In an unpublished manuscript Mrs. Reynold A. Spaeth, from data preserved in the notes of the late Dr. Spaeth, asserts that in the gibbons of Siam as a rule the males are dark and the females light in coloration, and that among young ones the males are gray and the females buff. Ex- ceptions to this rule are noted. It also is established that in certain at least of the species of Hylobates sexual dimorphism does not appear until rela- tively late in development and that the sexes consequently are confused during early life and the phenomena of coloration, therefore, are not readily related to sex. In 1830, George Bennett acquired in Singapore a specimen of siamang which he describes as a castrated Ungka ape. The anthropometric data presented, and the fol- lowing sentence, "The animal had been castrated, but the spermatic cord termi- nated in the scrotum in two small oval substances, rather larger than small peas" (Bennett, 1834, II, 171), justify the con- clusion that it was a young male siamang in which the primary sex characters were only partially developed. Our inference is supported by the observations of Pocock, who states that the male gibbon, owing to the relatively late appearance of sexual dimorphism, is often mistaken by scientists as well as laymen for either a castrated individual or a female, and the female for a castrated male (Pocock, 1905, p. 171, and more recently by Welch, 191 1, pp. 353 ff.). This matter is of peculiar inter- est and importance because sex, age, and physiological condition are as important in connection with descriptions of behavior as are species differences. HABITS OF LOCOMOTION Little is definitely known of the daily life of wild gibbons. Of the half score or so of competent naturalistic observers who have contributed to our knowledge, not one has pursued his inquiry long enough or exten- sively enough to obtain a reasonably com- plete and well-correlated account. The fol- lowing passage from Anderson is typical of HISTORY OF GIBBON 53 the descriptions to be found in the best scientific contributions. It was early morning and the air was resonant with the loud calls of this Gibbon; large troops were answering each other from the opposite banks, and the hills echoed and re-echoed the sound. The Hoolock is also common on the Kakh- yen hills, on the eastern frontier of Yunnan; and, there, too, my attention was called to them at daybreak when they passed up from their shel- tered sleeping-ground in the deep and warm val- leys to heights of about 4,000 feet. We, in the middle distance, first caught a faint murmur of voices; but every minute it became more and more distinct, till at last the whole troop rushed past in a storm of sound, vociferating "whoko!" "whoko!" and in a few more minutes their cry was heard far up the mountain-side. Considering that their progress is almost exclusively arboreal, the rapidity with which they make their ascent is wonderful. (Anderson, 1878, I, 2.) One may infer from this statement, and similar observations of other authorities, that the animals generally spend the night in sheltered regions and during the day as- cend the hills or mountains in search of food. The name Hylobates is appropriate be- cause gibbons are highly arboreal crea- tures. They are well fitted structurally for life in trees, whereas on the ground they are at a disadvantage. Almost every natu- ralist who has written about them has de- scribed their mode of progress through trees and also their way of walking. The following general statements seem to apply to all of the species of Hylobates, but the heavier and less agile siamang cannot safely be included. All observers agree with Anderson that the progress of gibbons through the trees is marvelously rapid. They use their arms to swing themselves from branch to branch instead of jumping or springing. It is said that they cover distances of thirty, or even forty, feet without evident difficulty or hesitation. They can change direction of motion while in the air and on landing are able to take a fresh start instantly. In- deed, their locomotion has been likened by many observers to the flight of a bird. Martin, whose general account of the genus Hylobates is at least the equal of 54 A STUDY OF ANTHROPOID LIFE any available, thus describes the "agility, power, and address" of a specimen of the agile gibbon which was exhibited in Lon- don in 1840. Fig. 33. The same wau-wau as that in fig. 32. Courtesy of H. C. Bingham and Mrs. R. Abreu. When at rest, her favourite position is that of sitting in a crouched attitude, at the fork of one of the branches of the tree in her spacious apart- ment, so as almost to shroud herself from view; and from this post she watches intently every- thing that passes around, or the motions of any person endeavouring to gain a sight of her. It is not without impatience that she submits to disci- pline: she has often turned upon her keeper with every demonstration of anger, and engaged with him in a struggle for the mastery. It is almost im- possible to convey in words an idea of the quick- ness and graceful address of her movements: they may, indeed, be termed aerial, as she seems merely to touch, in her progress, the branches among which she exhibits her evolutions. In these feats her hands and arms are the sole organs of locomo- tion ; her body hanging, as if suspended by a rope, sustained by one hand (the right, for example), she launches herself, by an energetic movement, to a distant branch, which she catches with the left hand : but her hold is less than momentary ; the impulse for the next launch is acquired : the branch then aimed at is attained by the right hand again, and quitted instantaneously, and so on, in alternate succession. In this manner, spaces of twelve and eighteen feet are cleared with the greatest ease, and uninterruptedly, for hours to- gether, without the slightest appearance of fatigue being manifested: and it is evident, that if more space could be allowed, distances very greatly ex- ceeding eighteen feet would be as easily cleared; so that DuvauceFs assertion, that he has seen these animals launch themselves from one branch to another, forty feet asunder, startling as it is, may be well credited. Sometimes, on seizing a branch in her progress, she will throw herself, by the power of one arm only, completely round it, making a revolution with such rapidity as almost to deceive the eye, and continue her progress with undiminished velocity. It is singular to observe how suddenly this Gibbon can stop, when the impetus, given by the rapidity and distance of her swinging leaps, would seem to require a gradual abatement of her movements. In the very midst of her flight a branch is seized, the body raised, and she is seen, as if by magic, quietly seated on it, grasping it with her feet. As suddenly she again throws herself into action. The following facts will convey some notion of her dexterity and quickness. A live bird was let loose in her apartment; she marked its flight, made a long swing to a distant branch, caught the bird with one hand in her passage, and attained the branch with her other hand; her aim, both at the bird and the branch, being as successful as if one object only had engaged her attention. It may be added, that she instantly bit off the head of the bird, picked its feathers, and then threw it down, without attempting to eat it. On another occasion, this animal swung her- self from a perch, across a passage, at least twelve feet wide, against a window, which it was thought would be immediately broken ; but not so : to the surprise of all, she caught the narrow frame-work between two panes with her hand, in an instant attained the proper impetus, and sprang back again to the cage she left — a feat requiring, not only great strength, but the nicest precision. She is fond of fruit, and often displays her dexterity in catching apples or plums, purposely thrown at her: however quickly they may be propelled by a vigorous arm, and although pretended throws may be made, to deceive or balk her, she never fails to catch the fruit, and that almost without an effort. (Martin, 1841, pp. 429-431.) So far as we have been able to discover, no study of any aspect of the remarkable translational activity of the gibbon has ever been made under carefully arranged experimental conditions. The measure- ments which might thus be obtained are much to be desired. That specific differences in agility have been noted is indicated by Tickell (1865, p. 197), who says that the white-handed THE HABITS AND LIFE HISTORY OF GIBBON gibbon is not nearly so active and lively as the hoolock. Several authorities state that siamangs move more slowly and are some- what less sure in their climbing than are the species of Hylobates. It is certain that gibbons climb with fa- cility and swing about in the forests with assurance and in such wise as to make rapid progress if they so desire. But when it comes to movement on the ground there is considerable variation in the descriptions which we have assembled. Almost all au- thorities agree that the general attitude in walking is erect with the soles of the feet placed flat on the ground, and the arms held either above the head where they wave in the air, or bent sharply at the elbow. By some it is assumed that the arms are used to aid in balancing, by others that this is a minor function and that they are merely held up out of the way. Again, some ob- servers state that the animals can walk with rapidity and ease if not frightened or hurried, whereas others consider this mode of progression difficult, unnatural, and fa- tiguing. It is also said that if frightened or for any other reason hurried, the gibbon either hops along excitedly or takes to quadrupedal locomotion. Certain comparisons offered by Pocock (1905) in an excellent article on the be- havior of a female specimen of the Hainan gibbon are pertinent. This author says gib- bons are unequaled among the anthropoid apes for proficiency in use of arms in arbo- real progression and in use of legs in ter- restrial progression. Their bipedal ability is surpassed only by that of man. In fact, Pocock's description, comparison, and dis- cussion of locomotion in the four types of anthropoid ape are at once so consistent with the data which we have assembled, so instructive, and so suggestive of genetic problems, that we quote him at length. If the Anthropoid Apes be ranged in series ac- cording to proficiency in bipedal locomotion, the order will be (i) Gibbons, (2) Gorillas, (3) Chim- panzees, (4) Orangs. Gibbons not only stand erect and habitually walk without putting the hands to the ground; they can even run with astonishing speed, a speed indeed comparable to that of Man, allowance being made for difference in size. Like Man they race away when scared; and, unlike the other Anthropoid Apes, they do not use their arms as crutches. Sometimes also, but rarely, they leap over the ground with both feet together.- Gorillas can stand and walk upright, but not with the ease of Gibbons, and it may be doubted if they ever run erect or leap, i.e., progress with both feet off the ground at one time; and they probably never run from danger, standing upright, as Man and Gibbons do. Their usual walk is quadrupedal. Chimpanzees, too, are essentially quadrupedal; and under ordinary conditions, and when in per- fect health, almost always get over the ground on "all fours," hke a Baboon or Rhesus. In this re- spect, indeed, they more resemble the Cercopithe- coid Monkeys than does any other Anthropoid Ape; and they are able to cover the ground with much greater speed than either Gorillas or Orang- utans; but I am unable to say if their quadru- pedal method is so fast as the bipedal method of Gibbons. Like Baboons, they can stand erect and walk to a certain extent, but not with the facility of Gorillas. The gait of young Orang-Utans may be de- scribed as a clumsy quadrupedal shuffle. I never saw one stand unsupported by the arms. Weak- ness of leg and weight of body make exclusively bipedal action, if not an impossibility, at least so great an effort that it may be doubted if it is ever resorted to. Their whole organisation suggests un- fitness for terrestrial locomotion. Thus, if the Apes be classified according to their quadrupedal activity on the ground, they will stand: (i) Chimpanzees, (2) Gorillas, (3) Orangs, (4) Gibbons. It is interesting to compare this series with one based upon dexterity in cHmbing and addiction to arboreal life. It is: (i) Gibbons, (2) Orangs, (3) Chimpanzees, (4) Gorillas. The Gibbons stand quite alone both in method and expertness; the others differ inter se merely in degree. The foregoing results may be briefly sum- marised as follows: — The Gibbons are the most expert climbers and bipedal walkers, the least ex- pert quadrupedal walkers. The Orangs rank sec- ond in climbing, third in quadrupedal and fourth and last in bipedal activity. The Gorillas take fourth place in climbing, second in bipedal and second in quadrupedal activity. The Chimpanzees stand third in cHmbing, third in bipedal and first in quadrupedal powers. Since, therefore, the action of Monkeys, whether Cercopithecidae, Cebidae, or Hapalidae, and of Le- murs is essentially quadrupedal, the fore and hind 2 "These and the following statements and re- flections are based upon my own observations of the Anthropoid Apes that have come under my notice in the Society's Gardens." A STUDY OF ANTHROPOID LIFE limbs being used to an approximately equal ex- tent, both in terrestrial and arboreal locomotion, it may be inferred that the Chimpanzees have de- parted least in these respects from the primitive Primate stock; the Gorillas a little more in the line of bipedal erection and, concomitantly, loss of climbing power; the Orangs still more in the di- rection of loss of terrestrial activity and increase of arboreal cxpertness; the Gibbons most of all in the line of bipedal activity, dexterity in hand- climbing, and loss of quadrupedal power. This serial arrangement of the Apes is the exact opposite of the one prevalent in text-books, where the order adopted is based upon structure with Man placed first as the standard for comparison. It suggests that for the origin of Gibbons we must look not to forms resembling any known Cerco- pithecoid type, but to forms which had already acquired the Simiine or Anthropomorphine char- acteristics and had either lost or never learnt the method and skill in climbing found in the former group. They may have started from a type some- what on a level with the Chimpanzees with re- spect to terrestrial and arboreal activity; and to swing with greater facility from tree to tree and to obviate the risk of injury in case of a fall, it is highly probable that they have become dwarfed in stature and grown lighter in build. Their mus- cularity and length of arm, slightness of body and strength of leg, all factors of importance in en- abling them to traverse the jungle and, in case of a miss or a breaking branch, to drop lightly to the ground and run to the nearest tree for safety, were probably perfected concomitantly. That Gib- bons are able to drop with safety a considerable distance is substantiated by the fact that Mr. de St. Croix has seen his specimen come to the ground without injury from a height of about 20 feet. When leaping to the ground Gibbons swiftly draw up the knees as the feet touch, exactly as a man does under similar circumstances, to break the shock. (Pocock, 1905, pp. 178-179.) When resting the gibbon ordinarily sits hunched up in the crotch of a tree, with its long arms folded across in front of it and sometimes resting on the knees, the head bent forward and the chin nearly in con- tact with the drawn-up knees and folded arms. Those who have observed it in cap- tivity frequently state that in sleeping it lies stretched out on back or side. The evi- dence suggests that this is an adaptation to the conditions in captivity instead of the natural attitude in quiescence or sleep. By several observers it is stated that the ani- mal readily becomes accustomed to sleep- ing in a bed and takes satisfaction in neatly covering itself. There is no reason to doubt the fact because it is well established that all of the anthropoid apes appreciate com- forts and speedily avail themselves of any Fig. 34. White-handed gibbon, H. lar. Courtesy of Xew York Zoological Society, E. R. Sanborn, photographer. facilities for increasing their satisfaction in rest or activity which may be provided in their captive environment. Relative to aquatic locomotion Candler writes: There is a point about the Hoolock that strikes me as very extraordinary, and that is the fact that he cannot swim. I had been told this by both na- tives and Europeans, but I confess I was some- what sceptical about it until I tried experiments myself. We put a full-grown Hoolock into a big tank in 10 feet of water. He struggled helplessly, as a boy would before he learns to swim. He sank twice, with head thrown back and arms waving frantically, and we wxre obliged to rescue him al- most asphyxiated and choking in the most human way. This weakness he shares with man, but I do not know whether (or not) it has been noted in the other anthropoids. It is a significant fact that the range of the Hoolock is bounded by two vast rivers, the Brah- maputra on the north and the Irawaddi on the south. It may well be that, with his natural aver- sion to water, these rivers have confined him to THE HABITS AND LIFE the comparatively limited stretch of country he occupies. Travelling high up in the jungle, he could swing easily across the ordinary streams which would come in his path without having to take to the water. The monkeys of India take readily to water, and it is a pretty sight to see them spring out from a lofty overhanging bough and drop, one after another, with a splash into the stream, and strike out boldly for the further bank. (Candler, 1903, pp. 188-189.) The natural ability of the gibbon to swim has been tested also by Bennett (1834, II, 1 51-152) with definitely nega- tive results. From the few observations re- ported it may tentatively be inferred that the animal does not naturally take to the water and is unable to swim. DIET AND HABITS OF EATING AND DRINKING It is established that the chief natural foods of the gibbon are vegetable growths. They include various wild fruits, berries, grains, leaves, grasses, shoots, and roots. Some observers state that certain animal foods are also included in the natural diet, as, for example, various insects and other small invertebrates, birds' eggs, and occa- sionally birds themselves. The dietary in- I formation is meager and unsatisfactory, since the evidence is mostly indirect. It is entirely possible that some species or indi- viduals may be exclusively vegetarian, whereas others in varying degree seek ani- mal products. The diet of captive specimens, although of relatively little naturalistic interest, has : practical significance because of varied rea- isons for maintaining specimens in confine- ment. It is reported that they readily eat cooked grains, fresh and dried fruits, raw eggs, meal worms, vegetables in great va- riety either cooked or raw, and in some in- I stances chicken, beef, or other meats in small quantities. All things considered, we may conclude that they are primarily vegetarians, but I that like man they are highly adaptable in their dietary tastes, preferences, and re- quirements, and may be taught to eat al- most anything which is not physiologically HISTORY OF GIBBON 57 injurious. Some captive specimens have been maintained chiefly on a meat diet, but ordinarily a vegetable diet is used on ac- count of convenience and economy. Tickell (1865, p. 198) records the important ob- servation that the young white-handed gib- bon, when fed solely on plantains or on milk and rice, is likely to lose its hair, as a result presenting a most ridiculous appear- ance. Few recover from this condition, but a change of diet, especially enabling the animals to help themselves to insects, in some instances results in the reappearance of the hair. Our principal sources of information on diet in nature and captivity are the fol- lowing authors: Bennett (1834), Harlan (1834), Rennie (1838), Martin (1841), Tickell (1865), Schmidt (1886), Blanford (1889-91), Klein, A. (1894), Candler (1903), Elliot (1913), Robinson (1925). In general, gibbons have the habit of taking water by either sweeping the arm along the moist leaves of forest trees or by dipping the hand and forearm into water and licking the accumulated supply from the fingers, back of the hand, and hair of the wrist. This habit is perfectly natural in view of the facts which have already been presented, for the tree habitat and the long arm of the animal render this method of obtaining water convenient and appropri- ate. There are undoubtedly species and in- dividual variations in manner of drinking and the reports on the drinking habits of captives vary widely and naturally enough differ in many respects from those based on observations in nature. We have not been able definitely to establish species dif- ferences. Hand-drinking, as it may be called, seems to be universal in the gibbon family, but a particular captive specimen may use the hand either as a scoop to take up water or, somewhat as in its wild envi- ronment, by dipping and licking off the accumulated drops. Another individual, or perhaps the same one under slightly differ- ent conditions, may place its lips to the water and drink directly. Occasionally it has been reported that an individual would 58 A STUDY OF ANTHROPOID LIFE raise the vessel of liquid to its lips and drink in human fashion. Blanford (1889-91, pp. 7, 9) states that the hoolock drinks with its lips, putting its head down to the water as monkeys do, whereas the white-handed gibbon drinks by scooping up the water in its hand. On the other hand, Pocock (1905, p. 176) states that both the hoolock and the white-handed gibbon habitually drink by dipping the back of the hand and the knuckles into the water and licking it off. Strictly speaking, they do not scoop up the water but merely dip the hand and arm in. The same author describes direct drinking on the part of a Hainan gibbon in captivity. That this was an acquired adaptation is rendered prob- able by the fact that an injury to the indi- vidual's right hand rendered that unusable and that the left hand frequently was used for holding to some object while water was taken. These various accounts of methods of drinking are peculiarly instructive as indi- cating dangers of misconception or inade- quacy of description when observation is limited to a single captive specimen, and the life experience and conditions in cap- tivity are not fully described. Our con- sideration of the sum of information leads to the conclusion that the practice of dip- ping is of primary importance, and that the different authorities have noted variations of this practice or deviations from it which are related to species characteristics and habits and to adaptations to conditions of captivity. LIFE HISTORY All observational reports agree in indicat- ing that the several species of gibbon are gregarious, living in groups of varying size. Sometimes undoubtedly these are family groups; again the males, if not also the females, appear to be segregated. But more particular description of gregarious- ness logically belongs in the chapter on af- fectivity, and the topic is mentioned here as introductory to consideration of sex and reproduction. It is significant that the literature con- tains few references to courtship and mat- ing activities, and almost no definitely es- tablished facts. Turpin (1771, p. 309) says that "they [the gibbons] do not offer a scandalous spectacle of unbridled passion." This casual remark indicates a contrast be- tween the behavior of gibbons and that of monkeys and great apes. The utter lack of description of sex activities indicates, we believe, the relative difficulty of observa- tion and suggests that shyness, timidity, or perhaps seasonal mating, may restrict exhibition of sexual behavior. It may be a matter of affective constitution, strength of sex impulse, or reaction to the presence of an observer. But, whatever the reasons, ignorance of the sex life of the gibbon is very nearly complete. Concerning age, sexual maturity, and the phenomenon of menstruation we cite the following observations. The occurrence of menstruation in gib- bons is attested by Buffon (Barr's transla- tion, 1797, IX, 187) and by Harlan (1834, p. 53). More recently a specimen carefully observed by Pocock furnished exception- ally valuable information. It was received in London in January, 1904, having for- merly belonged to Mr. E. H. de St. Croix who had procured her in the Island of Hainan in July, 1897. She, therefore, had been in captivity about six and one-half years. When captured she w^as thought to be about six weeks old, but within six months she was practically independent. It is assumed that she probably was born in 1897. Pocock (1905, p. 170) arranged for systematic observation of this Hainan gib- bon. Menstruation is reported to have be- gun in December, 1903, when the animal was approximately seven years old and had achieved her growth. Subsequent svstem- atic observation indicated that the interval between menstrual discharges was approxi- mately a month, and that discharge con- tinued for two or three days. Cessation of menstruation occurred for two winter months during which the gibbon suffered from influenza and diarrhea. THE HABITS AND LIFE HISTORY OF GIBBON Welch (191 1, p. 355) likewise reports menstruation and comments thus on its late appearance: "The delayed develop- ment of the scrotal bag and diminutive size of the testicles correspond to the late com- mencement of menstruation. ... It seems to be the normal course that in Hylobates menstruation is delayed until a much later period than is normal in Man." We may tentatively conclude that the gibbon becomes sexually mature at from five to eight years of age and that men- struation occurs at intervals of approxi- mately thirty days. On the basis of evidence which we shall exhibit in subsequent paragraphs the period of gestation is supposed to be approxi- mately seven months. As a rule there is a single birth. Of this Tickell (1865, pp. 197-198) writes: "The young seldom reach maturity when deprived of liberty. They are born generally in the early part of the cold weather, a single one at a birth, two being as rare as twins in the human race. The young one sticks to its mother's body for about seven months, and then begins gradually to shift for itself." Pertinent also are the following state- ments from Blanford and Forbes: "But a single young is born at a time. Neither the period of gestation nor the age at which these animals become adult appears to have been ascertained." (Blanford, 1889-91, p. 7.) "The female produces but a single young one at a birth, of which she takes I the greatest care. She carries it about, clinging to the under side of her body, for many months. It is said that she even takes it to the waterside from time to time, and with much solicitude, and in spite of its cries and resistance, washes its face." (Forbes, 1894, II, 151.) It may here be remarked that the face washing is thought by most authorities to be a misinterpreta- tion of the behavior of the female as with baby clinging to her breast she bends over to dip water from a pool and lick it from her hand. We can readily imagine that the female gibbon, observed at a distance. drinking in its peculiar fashion might ap- pear to be washing its infant. Little is known of reproduction and the family life of either gibbon or siamang in freedom, and commonly it has been stated that these animals do not breed in cap- tivity. It is our good fortune to be able to present certain rarely interesting observa- tions. Reynold A. Spaeth, who devoted some months to an intensive study of problems of reproduction in the gibbons of Siam and whose life was sacrificed to the risks of tropical research, left notes on which Mrs. Spaeth has based a most interesting de- scription of "The tree- walkers of the tropics." With her permission we are sev- eral times referring to her husband's obser- vations as reported by her, and we here quote a paragraph which is of peculiar value. Dr. Spaeth found that the gibbons were for the most part in family groups. So far as he could as- certain, they have their young in the early sum- mer and spring, and almost all the females that he collected were either just going to give birth to a young one or were already suckling this year's baby. On one occasion he came upon a group of males alone in a tree early in the morning, con- versing in the typical male gibbon tones, and he concluded that it was some sort of bachelors' club gathering. But as a rule he found what appeared to be families. The gibbon has only one young a year and it takes three or four years for them to mature, so a family frequently consisted of two or more young ones in various stages of growth beside the father and mother. . . . They hang onto the mother with an extraordinarily strong grip as she swings thru the trees. She appears not to be in the least incommoded by the baby hang- ing to her and swings along as unconcernedly as tho she were alone. Mrs. Spaeth in her next paragraph reports birth of two gibbons in the "compound" of A. W. Ogilvie, Prae, Siam, and remarks: Mr. Ogilvie's gibbon family is the only instance on record of the gibbons breeding in captivity. (From unpublished manuscript, "The Tree- walkers of the Tropics," by Edith E. Taussig Spaeth.) The facts are thus reported by Ogilvie: Records of the Gibbon of Siam {Hylobates lar) breeding in captivity, are I believe unknown and 6o A STUDY OF ANTHROPOID LIFE the following instance, although the animals were not in strict captivity, is interesting. In April 1Q14 I bought and turned loose in my compound five gibbons, two white and three black. One of the black ones subsequently became savage and had to be shot, but the other four lived amicably together until March 1920 when one of the white ones was noticed to be pregnant and in May gave birth to a young one. A black gibbon who was obviously the father attached himself to her, and the other two were chased from their accustomed trees and never allowed in the compound. At the time of writing the young gibbon though over two years old and quite big enough to fend for itself still clings to its mother when she moves rapidly from tree to tree, and more remarkable still, is nursed by her and has never been seen to take any of the solid food provided for the other monkeys. (Ogilvie, 1923, p. 137.) Remarkable in this instance is the pro- longed period of nursing and of dependence of infant on mother. We have discovered authoritative report of two other births in captivity. They oc- curred in the Rangoon Zoological Gardens during 1923 and 1924. In presenting report on these cases Robinson emphasizes the delicacy of the white-handed gibbon and usefully describes the method of housing and caring for these apes in the Rangoon Gardens. Since his brief account of circum- stances of mating, birth, and relations of infant to mother is unique, we quote fully: We find it impossible to leave a male and a fe- male in the same cage. We selected a pair of gib- bons that we had had for seven years and which had not been sick during that period. It was re- ported to the Superintendent that these two had been seen copulating once in the early part of November 1922, and, as the young one was born on the ist of August 1923, the period of gestation was thought to be about nine months. When the father was let into the outer run for exercise, it was noticed that the mother took her seat close to the expanded metal on the side of the run. The male then clung to the expanded metal opposite her, and copulation was effected through the net- ting. In the case of both the young ones born, they were born at night, and the day before the birth the mother refused her food. She seemed dull, restless and frightened. From the appearance of the cage on the following morning, it appeared that the mother must have dragged about the in- fant until the placenta got broken off. The same was observed on the occasion of the second birth. She kept the baby pressed close to her breast and, from time to time, pulled back its head, gazing at it eagerly and displaying the utmost pleasure in it. She hardly ceased examining it and turning it over Fig. 3 5. A baby gibbon in Siam, species undetermined, said to be less than a year old. Courtesy of Mrs. R. A. Spaeth. and stroking it. She kept it clean with her hands and, for some weeks, would not allow anyone to see it. The first baby died owing to a catastrophe. The mother and child had been let out into the outer run and, as was perhaps natural, she took the child to the father's cage to show it to him. He took hold of the baby's finger and was fondling it when something apparently frightened the mother, who desired to retire. The father objected and held on to the baby's finger and, between the two parents, the unfortunate infant's finger was pulled off, and it died of septic poisoning on the 12th September 1923. The parents were observed to copulate between the 15th and 23rd of October 1923, many times, and the second infant \vas born on the 19th of THE HABITS AND LIFE HISTORY OF GIBBON 6i May, 1924. This puts the period of gestation at about seven months, and it would appear that it could not have been much longer. Enlargement of the breast, and fullness of the stomach only showed in the mother in the advanced stage of pregnancy. The infant clung on to its mother's hair, but the mother kept her arms round it in the earlier stages, and, whenever she could be induced to leave her retiring stage at the top of the cage, she always supported the infant as she came down with her thigh or her foot. She fed the infant from her breasts, and did not allow it to partake of any other food. The baby was born with its eyes open ; the head and ears were comparatively large. It had a mod- erate quantity of thick hair on the head, and thin, soft and downy hair on the back. There was little or no hair on the outer aspect of the arms and thighs, while the other parts of the body were quite bare. It was impossible to find out anything about its dentition; but the first gibbon which died within six weeks of its birth had four in- cisors at the time of its death. After eight weeks the hair has grown very thick and luxuriant on the head; and the back, the outer aspects of the arms, thighs and hands are now also fully covered with thin and soft hair; while the abdomen, the forehead, chest and buttocks are still bare. When born, its face was heavily lined and wrinkled, but in a few weeks the skin has smoothed out; the face is clear and, from looking an old and decrepit object, it now appears young and smooth. We had kept the outer doors of the cage shut, so that the mother should not be disturbed by visitors, and the only person she saw was the Superintendent, who visited her daily and saw to her food. When it was about four weeks old, I visited it, and, when we opened the doors, the mother and child were on the upper shelter. There were only the Superintendent and myself and a keeper at the back, I called the mother and of- fered her a mango; she at once came down and seemed to be quite without fear. She knew us all, which may perhaps account for that. It was inter- esting to note the way she clambered down, sup- porting the baby at each step, and, when seated at the front of the cage, peeling and eating the mango with one hand, she kept holding out the 'baby's hand towards us, with the intention prob- 'ably of teaching it to catch hold of the wire net- ting. This gave us a very excellent view, and time to record the progress made in the matter of the jhair, but we could see no sign of teeth. 1 We have so far not attempted to take any jphotographs ; indeed, it would be almost impos- sible, partly because the mother would not come forward with the child, and partly because in the rains in Burma the light is too poor to enable photographs of any value to be taken of animals inside a small cage. It is hoped to be able to do io before long. (Robinson, 1925, pp. 456-458.) Of the span of life in gibbon and sia- mang nothing is definitely known. Accord- ing to Harlan (1834, p. 59), who in turn cites Burrough as his authority, the natives of Assam assert that the gibbon may live to an age of twenty-five or thirty years. In a few instances specimens have lived in zoological gardens for fifteen or twenty years. Although this account of the life history of the gibbon is a mere sketch which lacks completeness and satisfactory verification of fact, we believe that it fairly represents the status of knowledge and we hope that it exhibits extraordinarily important oppor- tunities for naturalistic and experimental observation. GIBBONS IN CAPTIVITY Gibbons have the reputation of being very delicate and difficult to keep in European and American zoological gardens. There are records of many years' life in captivity, but the average appears to be a few months. We have obtained information from the directors of nearly a score of ex- hibition parks. One specimen of white- handed gibbon has lived for more than twenty years in the Philadelphia Zoological Garden. Undoubtedly the physique, eco- logical needs, habits of life, and tempera- ment of these apes unfit them for close confinement and a sedentary existence. It is well known that they are peculiarly sensi- tive to subnormal temperatures and that they succumb readily to exposure to drafts or cold and to inadequate or otherwise un- suitable nourishment. Even their social en- vironment appears to be important for health and contentment. Most frequently mentioned as causes of death in captivity are respiratory diseases, due doubtless to unreasonable exposure, and intestinal disorders induced by the combination of improper foods and expo- sure. "The Gibbon is a very delicate ani- mal, in spite of its selecting usually an elevated habitat, and rarely survives long in captivity, generally succumbing to some pulmonary complaint." (Elliot, 19 13, III, 62 A STUDY OF ANTHROPOID LIFE 150.) And of the hoolock, Candler (1903, p. 187) says: "Owin^ to its extreme deli- cacy and the great difficulty experienced in keeping it alive in confinement, it does not often find its way into European collec- tions. Even in the Calcutta Zoological Gardens it is difficult to keep Hoolocks alive for any length of time. They often succumb to pneumonia, or if they escape actual disease they mope and die from the effects of confinement, or possibly from dep- rivation of some article of diet which in the wild state they have been accustomed to." That the animals may be satisfactorily maintained in a semi-wild condition in their native countries is indicated by the statements of Mrs. Spaeth. But having critically examined all the information available on the constitution of the gibbon and its relations to captivity. we are unable to subscribe to the prevalent opinion that it is peculiarly delicate and in- capable of adaptation to new conditions of life. Instead, it seems to us that these ex- ceptionally interesting anthropoids are to a considerable extent the innocent victims of human ignorance, stupidity, and careless- ness. Usually we fail lamentably to protect them from infectious diseases, or to cure disorders once contracted. We fail likewise to maintain proper hygienic conditions, a balanced ration, and to provide suitable exercise and adequate social environment. Although unquestionably there are differ- ences in degree of hardiness among the genera, species, and individuals of anthro- poid apes, biologically intelligent care, we feel assured, will suffice to maintain almost any normal specimen in healthy and con- tented captivity for a long time. CHAPTER SEVEN AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON ONE takes pleasure in raising this species of monkey [the 'onke,' Siamese gibbon?] because they are gentler than the others. . . . Economical and dexterous, they never break or smash anything. Friends of peace, and full of compassion, they wish to embrace those who weep, and their pity redoubles in pro- portion as they hear the groans of the un- happy; they never abandon those whose tears have not dried." Thus speaks the Siamese missionary Tabraca through Tur- pin (177 1, p. 309). It seems to have been settled by this gentle spirit that our pri- mate fellow creatures should be described with sympathetic anthropomorphism. One may respect the sentiment while question- ing both the accuracy and the adequacy of the description. The foregoing chapter has offered glimpses into the affective life of the gib- bon. It remains now to attempt a con- nected and, as nearly as may be, complete description of affective expressions. If it were our responsibility, we should be eager to apologize for meagerness of knowledge, insight, and interest. Evidently in this sphere of psychobiology we know only in part, and it may be suspected that the larger, if not also the better, part of ac- quaintance with the emotional traits of the gibbon is yet to be achieved. With the scanty information which we have been able to gather from a scattering and barely scientific literature, we shall do our best to indicate facts, informational trends, prob- lems, and opportunities. But our descrip- tion will necessarily be an indefinite sketch instead of a finished and accurate portrait. Oftener than any other the word gentle appears in accounts of the temperament and disposition of gibbons. There is per- fect agreement among observers that they are shy, timid, wary; good-tempered, af- fectionate, gentle; readily trained when young, fond of petting or cuddling, and ap- preciative of human kindness. Exceptions test this rule, and in any particular captive individual, whatever the species, one may happen upon quickness of temper, irrita- bility, and resentment of human attentions. Usually friendly and approachable even by strangers, this slightly built anthropoid is capable of biting savagely and of inflicting serious wounds. Seldom, however, is it the aggressor except under extreme provoca- tion. Nevertheless, it is wise for one who is inexperienced in handling them, or lacking in self-confidence, to await their advances instead of forcing attention. Like the other anthropoid apes they are quick to detect and resent unfriendliness or unkindness, and long remember such experiences. Mal- treatment or cruelty from a man may, it appears, make them suspicious of all men, while remaining friendly and trustful of women (Martin, 1841, p. 431). Such con- ditioned behavior we often misunderstand or misinterpret in ignorance of its history. Of the hoolock, Burrough, as quoted by Harlan (1834, pp. 57-58), says: The individual in question became so tame and manageable in less than a month, that he would take hold of my hand and walk with me, helping himself along at the same time with the other hand applied to the ground as described above. He would come at my call and seat himself in a chair by my side at the breakfast table, and help himself to an egg, or the wing of a chicken from my plate, without endangering any of my table furniture. ... In temper he was remarkably pacific, and seemed, as I thought, often glad to have an opportunity of testifying his affection and attachment for me. When I visited him in the morning, he would commence a loud and shrill Whoo-whoo-whoo-whoo, which he would keep up often from five to ten minutes, with an occa- sional intermission for the purpose of taking a full respiration; until finally, apparently quite 64 A STUDY OF AXTHROPOIl) LIFE exhausted, he would he down and allow me to comb his head, and brush the \on<r hair on his arms, and seemed delighted with the tickling sen- sation produced by the brush on his belly and legs. This description is of special interest be- cause it refers to an adult individual. It is noteworthy, writes Heck (1922, p. 622), "what an irresponsible tendency gib- bons have to allow themselves to be cud- dled and petted." Certain, if not all, species and many individuals are extraordinarily gentle, friendly, and eager for human kind- nesses. The siamang differs from the true gib- bons no less, it would appear from our im- perfect information, in disposition than in structure. Raffles (1822, p. 243) character- izes it as bold and powerful, whereas the other gibbons are timid and gentle. Yet Forbes, an equally reliable authority, de- voted to exactitude of description, reports of a young siamang, found clinging to its dead mother and brought in alive, that in a very short time it became a most delight- ful companion. Its expression of countenance is most intelli- gent and often very human; but in captivity it generally wears a sad and dejected aspect, which quite disappears in its excited moods. With what elegance and gentleness it takes with its delicate taper fingers whatever is offered to it ! Except for their hairiness, its hands, and, in its youth at all events, its head, seem to me more human than those of any other Ape's. . . . The gentle and caressing way in which it clasps me round the neck with its long arms, laying its head on my chest, and watching my face with its dark brown eyes, uttering a satisfied crooning sound, is most engaging. Although it often inflates its laryngeal sac, it rarely gives utterance to more than a yawn-like noise or suppressed bark; but this dila- tation has no reference apparently to its good or bad temper, although, when very eager and im- patient for anything, a low pumping bark is ut- tered. Every evening it makes with me a tour round the village square, with one of its hands on my arm. It is a very curious and ludicrous sight to see it in the erect attitude on its somewhat bandy legs, hurrying along in the most frantic haste, as if to keep its head from outrunning its feet, with its long free arm see-sawing in a most odd way over its head to balance itself, and now and again touching the ground with its finger-tips or its knuckles. (Forbes, 1894, II, 168-169.) Sharply contrasting with this picture of the siamang is that of Duvaucel, who was at one time employed as naturalistic ob- server in Sumatra by Sir Thomas Stamford Raffles. The passage which we venture to quote was originally published in E. Geo- ffroy-Saint-Hilaire and ¥. Cuvier's Histoire Naturellc dcs Mammijeres. It has been often quoted, much discussed, and also ad- versely criticized. Servitude, however long, seems to have no in- fluence in modifying the characteristic defects of this ape [the siamang], his stupidity, his sluggish- ness, and his awkwardness. It is true, that a few days suffice to make him as gentle and contented as he was before wild and distrustful; but, con- stitutionally timid, he never acquires the famili- arity of other apes, and even his submission ap- pears to be rather the result of extreme apathy than of confidence and affection. He is almost equally insensible to good or bad treatment; gratitude and revenge are sentiments alike for- eign to these animated machines. All his senses are dull and imperfect; if he regards an object it is manifestly without interest — if he touches it, it is involuntarily. In a word, the siamang exhibits an absence of all intellectual quahties; and if animals were to be classed according to their men- tal capacities, he would unquestionably occupy a very inferior station. Most commonly squatted on his hams, with his long arms twined round him, and his head concealed between his legs, a position which he also occupies while sleeping, he is seldom roused from his lethargy, nor does he break silence, unless at intervals, to utter a dis- agreeable cry, which in sound approaches to that of a turkey-cock, but which appears to be expres- sive of no sentiment, nor to declare any want, and which in fact expresses nothing; hunger itself does not arouse him from his natural apathy : in cap- tivity he receives his food with indift'erence, car- ries it to his mouth without avidity, and sees him- self deprived of it without testifying either sur- prise or resentment. (Duvaucel, quoted from E. Geoffroy-Saint-Hilaire and F. Cuvier, 1824. Le Siamang, p. 2.) Because it is at variance with almost all other reports this author's description fails to inspire confidence. Perhaps the most generous way to account for its contradic- tory nature is to assume that Duvaucel unwittingly observed and perhaps accu- rately described the behavior of a diseased or otherwise enfeebled and decrepit cap- tive specimen. In one of the very best early descriptions AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON 65 Fig. 36. Portrait of a gibbon. Unidentified, but probably H. hoolock. Courtesy of G. Krause. of the behavior of a captive siamang, Ben- nett (1834, II, 149) thus comments on his subject: On shipboard "he was so docile when at liberty, and so very much irri- tated at being confined, that he was per- mitted to range about the deck or rigging." And later this individual is mentioned as grave of look and mild of manner. EMOTIONAL EXPRESSIONS Among the many references in which, more or less incidentally, mention is made of affectivity or its expressions in the gib- bons, not more than a score are worthy of serious consideration, and even in these there is little well-established or indeed adequately stated information. One may reasonably infer from present evidences that the animals express varied emotional experience. We have attempted to arrange our materials in certain familiar affective categories, and although we recognize their inadequacy we present them as indication of the status of knowledge and to exhibit primary needs and obvious opportunities for research. Jealousy, resentment, anger, and rage gain varied expression. It is established that the gibbon is likely to resent attention given by its master or mistress to other animals, or indeed other individuals of its species. We have found no mention of jeal- ousy of persons, and we are not able to give from the available literature a worth-while description of the manifestations of what is referred to as jealousy by Schmidt (1886, p. 14), who speaks of the animal's resentment of the care of other nearby ani- mals and the belief that the gibbon may die if another is preferred to it. And for the following, Raffles is authority: It is the general belief of the people of the country that it will die of vexation if it sees the 66 A STUDY OF ANTHROPOID LIFP: j)rcfcrence given to anotlu-r; in corroboration of which I may add, that the one in my possession sickened in this situation, and did not recover until relieved from the cause of vexation by his rival the Siamang being removed to another apartment. (Raffles, 1822, p. 243.) This, by the way, is an inadequately founded belief, applied not only to the gibbon but to the other anthropoid apes. Undoubtedly there is basis for the state- ment that agreeable social environment is essential to the normal health and content- ment of the animals. Determined resent- ment of disagreeable treatment is tenta- tively described by a number of observers. For example, Blyth (1844, p. 465) writes: I can testify to the capability of these animals to inflict serious injury, from having witnessed a tame female of the Sumatran H. agilis suddenly attack her keeper, by springing up at him, grasp- ing his body with her four limbs, and biting at his chest, when it was fortunate for the man that her canines had been previously filed down; in conse- quence, as was said, of her having occasioned the death of a man at Macao. And the author adds by way of foot- note comment: From what I have seen of the Gibbon tribe when brought up tame, no animals could be more gentle and good-tempered; but the lady in ques- tion had good reason for the utter hatred which she bore to her keeper, who used to make her display her wondrous activity a hundred times a day, in swinging from bough to bough of a large artificial tree by means of her fore-limbs only, by frequent application of the whip. Anger and rage in these creatures, as in children, are readily evoked and gain free expression. Like the child, they quickly re- cover from emotional outbursts and there is evidence that the behavior is expected to achieve some desired end. Bennett has given a description of anger in the Ungka ape (siamang) which is confirmed and in certain directions supplemented by that of Tickell for the white-handed gibbon. At sunset, when he was desirous of retiring to rest, he would approach his friends, uttering his peculiar chirping note, a beseeching sound, beg- ging to be taken into their arms; his request once acceded to, he was as adhesive as Sinbad's old man of the sea; any attempt to remove him be- ing followed by violent screams. He could not en- dure disa[)pointment, and, like the human species, was always better pleased when he had his own way; when refused or disappointed at anything, he would display the freaks of temper of a spoiled child ; lie on the deck, roll about, throw his arms and legs in various attitudes and directions, dash everything aside that might be within his reach, walk hurriedly, repeat the same scene over and over again, and utter the guttural notes of ra, ra; the employment of coercive measures during the paroxysms reduced him in a short period to a system of obedience, and the violence of his tem- per by such means became in some degree checked. Often has he reminded me of that pest to society, a spoiled child, who may justly be de- fined as papa's pride, mamma's darling, the visi- tor's terror, and an annoyance to all the living animals, men and maid-servants, dogs, cats. . . . (Bennett, 1834, II, 152-153.) Anger it shows by a fixed steady look, with the mouth held open and the lips occasionally re- tracted to show the canines, with which it can bite severely, but it more usually strikes with its long hands, which are at such times held dangling, and shaken in a ridiculous manner, like a person who has suddenly burnt his fingers. (Tickell, 1865, p. I97-) One finds also references to the animals throwing themselves on the ground, fling- ing themselves about, and screaming loudly, when they are disappointed or provoked. Of the physiological concomitants of anger or rage the literature gives no infor- mation. It is entirely evident, even from avail- able imperfect descriptions, that timidity, fear, and terror are intimately related to resentment, anger, and rage, and that the former emotional and expressive condition may almost instantly give place to the lat- ter. Thus, for example, the anthropoid ape who is alarmed or actually frightened by an unfamiliar object or by the menacing behavior of another animal may become aggressive and vigorouslv express resent- ment or anger the moment the fear-inspir- ing object begins to retreat or withdraw. There are no quotable examples of the replacement of timiditv bv resentment, but we have often obser\'ed it ourselves in each type of anthropoid ape, and it is well known in man. Although it is repeatedly stated that gibbons are timid, there is a dearth of descriptive material on fear and AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON 67 Fig. 37- A gibbon expresses interest and surprise. Courtesy of G. Krause. terror. All that the literature actually sup- plies is a few instances of fear-evoking situations. Thus Forbes, of his own knowl- edge, tells of the unexpected terror and in- hibition of action in a group of siamangs which became isolated in some trees that were being felled: That they can leap the great distances from tree to tree ascribed to them is no doubt an accurate observation ; but they appear to be sometimes ter- ror-stricken and unable to perform these feats to save their lives. During the felling of the forest near this village, a small colony of Siamangs got isolated on a tree separated from the next clump by some thirty feet or so. They scampered up and down in the crown of the tree howling in the most abject terror at every stroke of the axe; yet they would not venture to leap the intervening space, and even, when the tree was falling, they did not attempt to save themselves by springing to the ground, but perished (Forbes, 1894, II> 169.) its downfall. According to Mitchell snakes disturb gibbons much less than they do the great apes. Tried with various kinds of snakes, the gibbons were least timid; a very small agile gibbon showed no fear and very little curiosity, while a full-grown example of the same species and a hoolock gibbon showed no panic, but re- treated very decidedly. It is possible that gibbons, as they are the most agile and completely arboreal of all the monkeys, run little risk from snakes and have partly lost their fear. (P. Chalmers Mitchell, 1912, p. 201.) Of the emotional categories suggested by aversion, disgust, shame, and modesty, we have found no noteworthy mention in the literature on the gibbon. This is of interest 68 A STUDY OF ANTHROPOID LIFE Fig. 38. Expression of fear in a gibbon. Courtesy of G. Krause. primarily as informational lack which doubtless can readily be remedied by the determined observer, and secondarily as in- dicating possible contrast between the gib- bon and the other anthropoid apes with respect to the existence or frequency of ex- pression of these modes of feeling. Grief and sadness are occasionally re- ferred to with the usual brevity and inade- quacy of description. The following is Forbes's account of the death of a gibbon: The Wau-Wau has a wonderfully human look in its eyes; and it was with great distress that the writer witnessed the death of the only one he ever shot. Falling on its back with a thud on the ground, it raised itself on its elbows, passed its long taper fingers over the wound, gave a woeful look at them and at his slayer, then fell back at full length — dead — "saperti orang" (just like a man), as his Malay companion remarked. He kept in captivity for a short time a specimen which was brought to him by a native, and it became one of the most gentle and engaging creatures possible; but when the calhng of its free mates reached its prison house, it used most pathetically to place its ear close to the bars of its cage and listen with such intense and eager wistfulness that it was impossible to retain it in durance any longer. It was accordingly set free on the margin of its old forest home. Strange to say, its former companions, perceiving perhaps the odour of cap- tivity about it, seemed to distrust its respect- ability, and refused to allow it to mingle with them. Amid the free woods we may hope that this taint was soon lost and that it recovered all its pristine happiness. (Forbes, 1894, II, 156-157.) Amusement, delight, and joy likewise are seldom mentioned and never adequately described in the literature. Yet their exist- ence in the gibbon cannot be doubted. Re- peatedly reference is made to the playful- ness of the young and to their evident sat- isfaction in amusing themselves by simple AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON 69 games which are played either with others of their kind or with human companions. Occasionally there are found references to attempts on the part of these creatures to express appreciation of human friendliness or kindness. Affection and sympathy for one another and for persons are more frequently men- tioned in the literature than any other types of emotional expression. From an anonymous writer we quote the following paragraphs descriptive of intraspecies sym- pathetic relations, and at the same time typical of the information offered by vari- ous authorities. Having read the letters of Dr. Gulliver and GJ.R. in Nature, Vol. VIII, pp. 103 and 163, in which the affection of monkeys for their dead is discussed, I think that I may perhaps be per- mitted to record my experience in regard to a certain class of monkeys that I have peculiar fa- cilities for observing, which is not in accordance with the observation of Mr. Forbes or G.J.R. I keep, in my garden, a number of Gibbon apes {Hylobates agilis) ; they live quite free from all restraint in the trees, merely coming when called to be fed. One of these, a young male, on one occasion fell from a tree and dislocated its wrist; it received the greatest attention from the others, especially from an old female, who, however, was no relation; she used, before eating her own plan- tains, to take up the first that were offered to her every day and give them to the cripple, who was living in the eaves of a wooden house ; and I have frequently noticed that a cry of fright, pain, or distress from one would bring all the others at once to the complainer, and they would then con- dole with him and fold him in their arms. But one morning one of the flock was found hanging dead in the fork of a tree, his comrades took no notice whatever of him, and were playing j and singing their peculiar song as usual close to j him ; on the body being removed they took no j notice whatever. A neighbor of mine who keeps a pair of these j apes, informs me that the male lately came home ! after an absence of two days very sick ; the fe- male, who had theretofore been very affectionate, carefully avoided him, and on his death a few days after showed the most thorough indifference. Very possibly the alleged affection for their dead may exist among some families of monkeys, and not among others. Though my apes live in com- iplete freedom, they have never shown any dispo- jsition to breed, though I have had some of them over two and a half years. (Anonymous, 1874, P- 243-) Referring, it is thought, to one species of gibbon, sympathetic expression is thus de- scribed : These animals were reserved, very gentle, and uncommonly cleanly as to their bodies and their food. They evinced great attachment for each other, as particularly appeared during the sick- ness of the female; the other holding her in his arms as a parent does her infant ! and after her death he immediately refused sustenance, and, as before stated, shortly died. (Lewis, 1834, P- 33-) From varied experience as hunter and superintendent of zoological park, Horna- day offers the following: With the Gray Gibbon, of Borneo, I am well acquainted; and after the three great man-Uke apes, it is to me the most wonderful of anthro- poids. They are very timid, the shyest of all Pri- mates that I ever hunted, and wonderfully suc- cessful in eluding the hunter. Nevertheless, so strong is their affection for their young, I have seen a whole troop that had made good its es- cape, return at the call of an infant Gibbon in trouble, and all reckless of their own safety come down within twenty feet of their deadly enemy. Very few other mammals will do this. (Hornaday, 1904, p. 12.) Attachment to persons is a matter of frequent record and there are several in- stances of special expressions of affection or sympathy which involve aggression on the part of the gibbon, as, for instance, in attempting to defend a human friend or companion. On the other hand, it is stated that in the flight of a troop, the mother gibbon sometimes abandons her young and again protects and defends it at the risk of her own life. Although the fact is not clearly established in the literature it may well be that such markedly different be- havior is related rather to the nature of the situation in which the animal finds itself than to individuality or species. SOCIAL RELATIONS As already remarked, all of the species of Hylobates and Symphalangus are known to be gregarious, but the social relations and habits of species differ somewhat. On the authority of Duvaucel, Martin says that the siamang is gregarious, and 1 70 A STUDY OF ANTHROPOID LIFE Fig. 39. Friendliness expressed by a gibbon. Courtesy of G. Krause. that each troop has a chief believed by the Malays to be invulnerable. The Ungka- puti (agile gibbon) is said to live in iso- lated couples (184 1, p. 419). This is con- firmed by Forbes (II, 153) who says it is found generally in small troops or in pairs. According to Tickell (1865, p. 196), the white-handed gibbon lives in bands of AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON eight to twenty individuals, although occa- sionally a solitary male is met with. The largest assemblages are those of the hoo- lock which are described by Blanford (1889-91, p. 6) as found associating in flocks of fifty to one hundred individuals, or even more. He also refers to the occa- sional solitary male. Only in the case of the siamang is the chief or leader especially mentioned, and in that case by only two authorities, Duvaucel and Broderip (1849, p. 244). With reference to the cooperative rela- tions of gibbons, next to nothing seems to be known. Some observers assert that troops, however large, will abandon a wounded comrade, and instances are re- ported of seemingly sympathetic coopera- tive action. It appears that the latter, and perhaps exceptional action, is more often observed in captive individuals than in na- ture, possibly because they are more accus- tomed to men and less dismayed by their presence or threats when there is occasion for sympathetic action. Nowhere have we discovered even the suggestion that any species regularly constructs anything in the nature of a shelter from the rain or the cold. It seems improbable that animals should live in bands as do the gibbons without developing a considerable measure of helpful cooperation. But obviously the subject is more appropriate for field study than for speculative consideration. Naturally there are more accounts of re- lations with human beings than with mem- bers of the species, and especially of friendships and playful activities. One of the most illuminating of these descriptions is that of Bennett, from whom we quote concerning the relations of his gibbon with a Papuan child. He was playful, but preferred children to adults. He became particularly attached to a little Papuan child (Elau, a native of Erromanga, one of the New Hebrides group,) who was on board, and whom it is not improbable he may have in some degree considered as having an affinity to his species. They were often seen sitting near the capstan, the animal with his long arm round her neck, lovingly eating biscuit together. She would lead him about by his long arms, like an elder leading a younger child: and it was the height of the grotesque to witness him run- ning round the capstan, pursued by, or pursuing, the child. He would waddle along, in the erect posture, at a rapid pace, sometimes aiding him- self by his knuckles; but when fatigued, he would spring aside, seize hold of the first rope he came to, and, ascending a short distance, regard himself as safe from pursuit. In a playful manner he would roll on deck with the child, as if in a mock combat, pushing with his feet, (in which action he possessed great muscular power,) entwining his long arms around her, and pretending to bite; or, seizing a rope, he would swing towards her, and, when efforts were made to seize him, would elude the grasp by swinging away; or he would, by way of changing the plan of attack, drop suddenly on her from the ropes aloft, and then engage in various play- ful antics. He would play in a similar manner with adults; but finding them usually too strong and rough for him, he preferred children, giving up his games with them, if any adults joined in the sports at the same time. If, however, an attempt was made by the child to play with him, when he had no incHnation, or after he had sustained some disappointment, he usually made a slight impression with his teeth on her arm, just sufficient to act as a warning, or a sharp hint, that no hberties were to be taken with his person; or, as the child would say, "Ungka no like play now." Not unfrequently, a string being tied to his leg, the child would amuse herself by dragging the patient animal about the deck : this he would good-naturedly bear for some time, thinking, perhaps, it amused his little play- mate; but finding it last longer than he expected, he became tired of that fun, in which he had no share, except in being the sufferer; he would then make endeavours to disengage himself and retire. If he found his efforts fruitless, he would quietly walk up to the child, make an impression with his teeth, in a ratio of hardness according to his treatment : that hint soon terminated the sport, and procured him his liberty. (Bennett, 1834, II, 158-160.) It has been remarked by various au- thorities that some at least of the gibbons tend to be more reserved toward men than toward women, and in some instances to exhibit very marked preferences. This ob- viously may be due on the one hand to the treatment received by the animal from persons, or, on the other, to sex interest. We have observed the latter in a mature female wau-wau. Entirely characteristic of the anthropoid 72 A STUDY OF ANTHROPOID LIFE apes, according to our experience and our acquaintance with the literature, is the fol- lowing intelligently appreciative behavior of a young gibbon toward his human care- taker. When teethintr my companion suffered severely — as the human infant so often does — both lo- cally and constitutionally, as indicated by boils and inflamed finger-tips. On lancing and poultic- ing the latter, and extracting some of its obstruct- ing teeth, the poor creature seemed greatly re- lieved, and I was delighted to watch it recover, without contracting for me any antipathy for the pain I had inflicted on it, but rather the reverse. (Forbes, 1894, II, i6g.) On the authority of the late Doctor Spaeth we have already reported that the gibbons of Siam seem for the most part to live in family groups. This observer discov- ered that he could distinguish the sexes of the species in point by differences in their calls. On this basis he identified certain so- cial groups as made up of males alone and certain others as mixed or family groups. Again we quote from Mrs. Spaeth to illus- trate various points in the affective life and social relations of the gibbon family: It is practically impossible to capture an adult gibbon alive, unless it can be made to come onto the ground. Swift and sure as they are in the trees, they are singularly awkward and helpless when they have to walk. Their legs are much shorter than the arms and, while they can grip branches and support their weight on their legs easily enough, their legs do not seem well adapted to walking. Frequently they help themselves along with their hands in an ungainly fashion. Once driven out of the trees, they can easily be cap- tured. But most of the tame gibbons are taken as babies, the mother killed and the baby saved. There are instances of a hunted mother gibbon dashing her baby down and so killing it, possibly because she feared its capture but more likely be- cause she found its weight too heavy in her ef- forts to escape. The baby gibbons, or "chenees" as the Siamese call them, make fascinating pets. They are most affectionate and intelligent little things, soft and furry with bright eyes and cling- ing arms. Lacking the mother to cling to, they quickly adopt master or mistress in her place and they appear to be perfectly happy travelling about house or compound clinging tightly to a skirt or a trouser leg. Even the older ones will jump readily into the owner's arms, twine their arms around his neck, and make an affectionate little sound like "Hu, Hu.'' There are hundreds of tame chenees in Bangkok and the Siamese grow very fond of them. They do not train them or use them for any purpose but apparently regard them as members of the family and they will almost never consent to sell them. The gibbon is far too mischievous and inquir- ing in temperament to be allowed to run free. They are not kept in cages but fastened by a collar and ring to a chain that permits them to dash about on a high bamboo pole or verandah railing or tree. They are incessantly active and it is extremely difficult to photograph them — they twist and turn and leap about and, if you ven- ture too close, they love to spring on your head, twine their arms about you and give you a quick little bite and leap away again. Except for occa- sional older animals, disillusioned and teased and jealous, they are generally friendly, but their sense of humor is of the slapstick variety and their little jokes are most disconcerting to a stranger. Before you know what has happened, they have nipped you here and there, thrown your hat into a klong and are back in the tree sampling the contents of your bag, and generally hurling each inedible article after the hat. One of the most entertaining sights is a dog and a chenee playing together. They look as tho they were lighting furiously but it is a toss-up which is enjoying it more. Near our house in Bangkok is a white gib- bon about four years old whose particular friend is a coal black dog. When the chenee is turned loose the two roll each other over and chase each other all up and down the house and thru the compound. If the dog nips the ape, the latter springs up on his bamboo pole out of reach but presently he leans down and grabs the dog firmly by the tail, indicating that he is ready to play again. A lady in Bangkok tells me that she had a little black gibbon but she had to get rid of it be- cause it would steal into her little boy's room when he was having his nap and tweak the child's nose. He did not hurt him but the child would wake up angrily and try to explain what was hap- pening, while the gibbon sat demurely in a comer. At last, one day, the mother happened to catch him in the act. (From Mrs. Spaeth's unpubHshed manuscript.) The subject of social relations, in certain of its aspects, will be continued in the next section, inasmuch as vocalization is pri- marily a social and emotional expression. THE VOICE OF THE GIBBON AND ITS USES The voice of the gibbon has remarkable range and carrying power. Perhaps chiefly because of this fact, vocalization has at- tracted the attention of naturalists, physi- AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON ologists, and anatomists, and, in general, the information available is more abundant and also more reliable and self-consistent than that on any other topic of the psy- chobiology of the animal. Extraordinary characteristics of vocalization early aroused speculation as to the nature of the vocal mechanism, and this curiosity was aug- mented by the existence of a conspicuous laryngeal sac in the siamangs. Although early descriptions of the voice and its mechanism are of relatively little scientific importance, one or two are worthy of quo- tation as indicating the nature of interest and the direction of inquiry. Bennett, in speaking of the neck pouch of the siamang, observes that it has been the subject of much speculation and is thought to be an appendage to the vocal organs. He then continues with report of his own observations: For often when irritated, I have observed him inflate the pouch, uttering at the same time a hollow barking noise. . . . The inflation of the pouch was not, however, confined to anger; for when pleased he would purse the mouth, drive the air with an audible noise into the sac; when yawning, it was also inflated; and in all in- stances, (except when excited by anger,) he would gradually empty the sac, as if he derived a pleas- ure from it. When the sac has been distended, I have often pressed on it, and forced the air con- tained within it into the mouth, the animal not evincing at the time any sign of its being an annoyance to him. When uttering the barking noise, the pouch is not inflated to the same extent as when he yawns. . . . To test the suggestion advanced by certain observers that the laryngeal sac is useful to the gibbon in swimming, Bennett one day placed his subject in a large tub of water. It was, as he reports, much fright- ened in this situation and "soon began to display a marked hydrophobic symptom, but not the least attempt was made to in- flate the pouch, although he was frequently submersed." (Bennett, 1834, II, 150-152.) The mechanism of vocalization is men- tioned also by Candler: As in other species of apes, there is a special modification of the larynx, which acts as a sort of resonating-box, and helps (I suppose) to make the sound carry, as it does, long distances. There is also a peculiar arrangement of the upper aper- ture of the larynx, with its small and inadequate looking epiglottis, which more resembles the ar- rangement in birds than the leaf-like epiglottis in man. (Candler, 1903, p. 188.) Attacking the problem of mechanism with the interest and technique of the mor- phologist, Giacomini examined the vocal structures of the gibbon with resulting ex- cellent description of the larynx. This au- thor states that the order of decreasing re- semblance of the structure of the larynx to that of the Caucasian, according to his own observations, is as follows: White male, Negro female, Bosch male. Chimpan- zee, Gibbon, Macacus, Cercopithecus, Go- rilla, and Orang-outan (Giacomini, 1897, p. 117). More recently Mott has dissected the larynx of the siamang and by aid of both horizontal and vertical serial sections sought to get such knowledge of its con- formation and relations as is necessary for an understanding of vocalization. Omitting his excellent anatomical description, we quote with reference to relations of sound production to characteristic features of anatomy. The loudness of sounds is increased proportion- ally to the amplitude of vibrations of the vocal cords, which is dependent upon the force with which the air is expelled through the chink of the glottis. The animal can by filling its laryngeal sacs bring into play the false vocal cords, which by their approximation necessitates a still further in- crease of propulsive force before the air can es- cape and set in vibration the vocal cords — in fact, the animal, when it wishes to emit a loud sound, can employ the "coup de glotte" of the singer. This "glottic shock" is produced by two muscular folds called the ventricular bands, or false vocal' cords, which in conjunction with some other mus- cles cause a complete constriction of the air-pas- sage above the true vocal cords. Their function is to protect the larynx during swallowing and to take any strain exerted by the respiratory muscles during effort, such as vigorous action of the arms or abdominal muscles involving the fixation of the chest. Thus action in coughing is of the nature of a spasm preceding an explosion of the breath. . . Such powers of emitting a loud vocal call of warning or of sexual attraction must play an important part in the self-preservation and pres- ervation of the species of these timid, agile, arbo- 74 A STUDY OF ANTHROPOID LIFE real animals. Doubtless, when this particular (iib- bon imitated the low-pitched bark of the dog he employed the whole of the vocal cord, but how did he imitate the shrill whistles of the guinea- pig? In order to imitate the shrill whistles of the guinea-pig it may be assumed that the animal em- ployed some means of considerably shortening the vocal cords and permitting only their free edge to vibrate, as in the human high soprano or falsetto voice in the male. (Mott, 1Q24, p. 1168.) Aside from the light thrown on the functional significance of larynx and laryn- geal sac by such investigators as Giacomini and Mott, as psychobiologists we are inter- ested in the implication that Mott's sia- mang imitated the bark of the dog and the shrill squeaks of the guinea pig. In general, the voice of the gibbon is shrill, penetrating, and in many instances musical. There are times, however, when to a human observer it is extremely disagree- able. Mott (p. 1 1 69) remarks: "The power of variations in pitch, which the Gibbon possesses, may be a means of emotional in- tercommunication which the other anthro- poids do not possess to the same degree." And referring especially to the possible sig- nificance of the laryngeal sac, Forbes (1894, II, 151) says that the voice of the gibbon "is very powerful and can be heard at a great distance, especially when they are howling in chorus. The Wau-Wau and the Siamang, the one without, and the other with, a laryngeal sac, are equally vigorous in this respect." The testimony of Blyth (1875, p. 4) is confirmatory of our general description, for he remarks: "They are further remarkable for their ex- ceedingly loud shouting cries, not unmusi- cal in tone, which are often uttered in con- cert, and differ more or less in the different species." So also is that of Welch (1911, p. 357)- Of curious interest is Shelford's refer- ence to the nature of the gibbon cry and the possibilities of imitating it. The Gibbons go about in large herds; their cry is extremely musical, and in the early morning the jungle fairly rings with it. I know no more joy- ous sound in nature than the dehghtful bubbhng shouts of these creatures. . . . The Malay and Kayan names for the Gibbon — Wa-wa and Wok — are onomatopa-ic in that they represent two notes of the series of whistles and hoots that the ani- mals utter. ... I know of no instrument on which the cry can be well imitated except a sim- ple thing made by the Kayans out of a bamboo- joint and known as Buloh Wok; with this the cries can be imitated with such great exactitude that the apes are often decoyed within a few yards of the performer. (Shelford, 1916, p. 6.) Undoubtedly vocalization differs signifi- cantly in the species of the family Hy- lobatidae, not only in accordance with the presence or absence of a laryngeal sac, but also in correspondence with variations in laryngeal structure and the use of the or- gans. Doctor Spaeth's observation that he could distinguish the sexes in certain spe- cies of Siamese gibbon by the voice is per- tinent. Whereas heretofore w^e have found it either impossible or obviously unprofit- able to attempt specific descriptions, the observational data on vocalization are rea- sonably adequate for this purpose. For the agile gibbon, Martin, with the assistance of Waterhouse, offers the follow- ing admirable description: The voice of this Gibbon is extraordinar}-. not only for its power and volume, but for the suc- cession of graduated tones in which its cry is uttered. In a room, it is overpowering and deaf- ening: it consists of a repetition of the syllables 00-ah, oo-ah, at first distinctly repeated, and as- cending in the scale, but at last ending in a shake, consisting of a quick vibratory series of descend- ing notes, during which the whole of the animal's frame quivers with the effort to produce them: after this, she appears to be greatly excited, and violently shakes the netting or the branch to which she may be clinging; which action being finished, she again traverses her cage, uttering the preliminary syllables oo-ah, oo-ah, till the shake again concludes the series. It is principally in the morning that the animal thus exerts this modu- lated cry, which is, probably, its natural call to its mate, and which, from its strength, is well calcu- lated for resounding through the vast forests. The following observations on the voice of this animal were obligingly presented to the Author, by Mr. Waterhouse : — "I should endeavour to give an idea of the whooping of the Gibbon (as far as the music is concerned, but not as regards the quality of sound), by comparing it to the tuning of a harp; first beginning with an E string, and repeating it at short intervals; then being altogether silent for a little time, and then beginning again; next, two AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON strings, as it were, are struck, E and E sharp (or F natural) : the second string is then screwed up, by half-notes, until it reaches the octave; the E and F natural, E and F sharp, E and G natural, &c., being struck nearly together. It must be ob- served, that, before the upper note arrives at the octave, the animal amuses herself by occasionally descending a few semitones, then ascending again, and so on. But when the octave is once gained, and has been sounded a few times, we may im- agine the upper string to be very rapidly let down by semitones; the lower note remaining the same as at first, and the two strings being always struck together.! The rapidity of the descending passage is equal to that of an extremely brilliant shake. The animal then remains quiet for a short time; after which follow two barks, each com- posed of the low and high E, sounded nearly together. "It appeared to me that, in ascending and de- scending the scale, the intervals were always ex- actly half-tones; and I am sure that the highest note was the exact octave to the lowest. In this passage the lips were engaged, and rapidly vi- brated during its execution. "The quality of the notes is very musical; and I do not doubt that a good viohnist would be able to give a correct idea of the Gibbon's com- position, excepting as regards its loudness. The Gibbon's voice is, certainly, much more powerful than that of any singer I ever heard. "One more fact I noticed, viz., that the Gibbon is usually a long time before she comes to the rapidly-descending passage; but when she has given it once, she soon runs through the pre- liminary part of her composition, and again comes to the descending passage." (Martin, 1841, pp. 431-432.) Allegretto. Accellerando. Crescendo. r-r- This description in musical terms is sup- plemented by report of Welch who says that in addition to the common chatter of excitement and laughter vi^hich all species of Hylobates make, the agile gibbon has a loud cry. "It appears, all through this rapid chromatic passage, as if the animal emitted two notes at a time, as in the music; but this is the effect of the rapid transition from the lower note to the up- ■per." This peculiar cry of E. agilis is best described by a word "whopp," and is shouted out, the mouth being wide open and the throat conspicu- ously dilated. It is only uttered once and then silence ensues for about thirty seconds, then an- other "whopp," then a period of silence, then an- other "whopp," and so on. Usually this cry con- tinues for about ten minutes, but a few times I have heard it continued for over an hour; and very occasionally the "whopp" is prolonged into a long loud screech lasting a minute or longer, the mouth being kept wide open the whole length of the screech and the throat dilated. I have never heard it uttered when playing or quarrelling with the H. hainanus (both species utter the common chatter at these times), but only when the H. agilis is swinging by itself. It is also a quite different sound from anything uttered by S. syn- dactylus. (Welch, 191 1, p. 357.) Of the nature of vocalization in the Bornean gibbon we have discovered only casual mention. One of the most interest- ing of the references is that of Elliot, who states that in this species, and in the wau- wau also, a peculiar bubbling noise is pro- duced (1913, III, 173). Pocock, contrasting the vocal expressions of the Hainan gibbon with that of the hoo- lock, writes: The voice of our Hainan Gibbon is quite dif- ferent from that of the Hoolock. It is a high- pitched trill all on the same note, and shriller even than the high note of the Hoolock's cry. It consists of from about three to six distinct cries repeated in very rapid succession, suggesting al- most production by vibration of the tongue, al- though, as a matter of fact, I believe the lips alone are instrumental in producing the effect. There is then a momentary pause, after which the cry is repeated. It may perhaps be represented in the following way : — hoo hoo hoo hoo — hoo hoo hob — hob hob hob hoo hob — &c. The Hoolock, on the contrary, cries as follows: — hah, hoo, hah, hod, hah, hah, hoo, hah. The "hoo" is on a lower note than the "hah," with which the cry fre- quently ends. The ordinary expression of anger or remon- strance in the Hainan Gibbon is a prolonged and guttural grunt, which is repeated rapidly and often, and frequently interspersed with a kind of warble when the excitement rises. (Pocock, 1905, p. 176.) Previously in our account of habitat and habits of life we have quoted Anderson's description of the call of troops of hoo- locks as in the morning they ascend the 76 A STUDY OF ANTHROPOID LIFE mountain sides from their sleeping grounds in the valleys (p. 53). The cry of the Hoolock is a characteristic sound in the Cachar jungle. It is a very pleasing note, rising and falling in intensity, and remind- ing one somewhat in its rhythm of a pack of beagles giving tongue on a scent which is waxing and waning in strength, as a larger or smaller number of the band join in the chorus. It is heard chiefly in the early morning, then all through the heat of the day there is silence, but towards evening, as the sun sinks, you may hear it again. Hooloo ! Hooloo ! Hooloo ! with the ac- cent on the Hoo syllable, is supposed to describe the sound, but it is really quite indescribable in writing. (Candler, 1903, p. 188.) Heck, seemingly reporting original ob- servations, writes: A Hoolock which I saw living in the London Zoological Park for some time, willingly used its voice and at every time of day, as soon as it was spoken to by the keeper or was excited by any- one through imitation of its sounds. I dare say that I have never heard the voice of a mammal, man excepted, which sounded to me more full- toned and pleasanter than that of this gibbon. At first I was astonished, later charmed, by these tones coming from the depths of the chest, drawn out to the fullest power and yet not at all un- pleasant. They may be represented by the sylla- bles hu, hu, hu. Other species emit a much less pleasant call. (Heck, 1922, p. 619.) Referring presumably, although of this we cannot be absolutely certain, to the Sia- mese gibbon, Mrs. Spaeth offers this inter- esting description: They are very noisy animals, with a shrill, mournful, penetrating call. Here in the suburbs of Bangkok we can hear them calling to each other from compound to compound as much as a quarter of a mile away, especially early in the morning. The native children love to imitate them and the apes respond and whoop wildly when the children give their call. To the Siamese the gibbons' cry may sound like "Pua, Pua" but to the European it is more like "Wup, wup, wu-u-u" going up in the scale and gathering vol- ume and shrillness until it ends in a very high trill. Dr. Spaeth described the initial "wup, wup" as "pumping sounds," as tho the animal were gathering steam for the final trill. The males, he said, made more of the pumping sounds and ended with a shorter trill than the females. As he wished particularly to collect females, he found it very convenient to be able to distinguish the sexes by the call. He found that the males called more frcfjuentiy in the early hours of the dawn, from six to eight. From eight to nine the females took up the cry, interrupted or answered from time to time by the males, and after nine o'clock the gibbons were quiet until late in the afternoon, when they called again but not so persistently as in the morninir. Although we have found several earlier references to the cry of the wau-wau than that of Forbes, they are relatively unim- portant, and we, therefore, introduce the subject with a quotation from Forbes: The Wau-Wau — the Malay name for this Gib- bon— is one of the first of the Quadrumana that makes its presence known to the traveller in Java, when he reaches its upland forest regions. In the evening, just about sundown, and more especially in the early morning commencing before sunrise and finally ceasing when the sun is above the tops of the trees, he will be surprised by a sudden out- break of what appears to be now the loud plain- tive wailings of a crowd of women, now the united howhng of a band of castigated children. The present writer's first acquaintance with this charming genus of Monkeys was made among the Kosala hills in Western Java, and it will ever remain with him as one of many most pleasant recollections of a long tropical sojourn. Their "woo-oo-ut — woo-ut — woo-oo-ut — wut-wut-wut — wut-wut-wut," always more dolorous on a dull heavy morning previous to rain, is just such a cry as one might expect from the sorrowful counte- nance so characteristic of the species of Hylobates. (Forbes, 1894, H, 156.) We have noted above (p. 75) the bub- bling sound produced, according to Elliot, by both the wau-wau (Hylobates leucis- cus) and the Bornean gibbon {Hylobates miilleri or concolor). From Heck we quote the following bor- rowed characterization of the wau-wau cry. The Wau wau begins, as Hasskarl tells me, with a few separate sounds: ua, uua, ua, ua. Then follows more quickly ua, ua, ua ; then: ua, uua. ua, ua. And at last a call becoming plain and more rapid, the u shorter, so that it almdsi sounds like a w, but the a longer, and the whdle company never fails to join in with like calls. In the same way sing four silver gibbons which re cently came into the Breslau Zoological Park. 1 ; largest begins a short ringing sound which lu comes louder and louder. The others fall in. the cry becomes strong, so that one could hear it all around in a circle, and it goes over into a r\>\\vi AFFECTIVITY AND ITS scale of twittering sounds which reminds one of a bird, and the whole bodies of the animals trem- ble. (Heck, 1922, p. 619.) Our own observation of the character- istic vocalization of the wau-wau agrees closely with Heck's description, but there are many variations of the cry and also other sounds produced by this species of gibbon which should receive scientific at- tention. For the white-cheeked gibbon, Boutan, as the result of observation of the species in nature and the study over a period of five years of a female kept in captivity, gives the most elaborate and thoroughgoing account of vocal expressions which is avail- able for any species. This author was inter- ested primarily in the problem of language. Incidentally he noted and carefully de- scribed the various forms and phases of vocal expression. The description is lengthy and of quite unusual value. We shall en- deavor to report its facts completely and to summarize the main conclusions. The white-cheeked gibbon {H. leuco- genys) possesses a voice of great compass. Owen (1868) is quoted by Boutan as stat- ing that the larynx in the gibbon is rela- tively large and the vocal cords well de- fined with ventricle intermediately deep and continued into a sac in the thyrohyoid space. The creature is capable of producing a great number of notes and it only "among mammals can pretend to sing." In the wau- wau the scale ascends and descends by half-tones through an entire octave. With the aid of phonographic records, Boutan studied vocal reactions, but he found it difficult to translate the sounds into letters, and he definitely states that the following words merely approximate the vocaliza- tions. I. State of satisfaction or well-being. Hoc, hooc, houc — general cry, when food pre- sented or known person or animal in sight. Hoc, houg, houg; Hag, couag, gouaggac — cry of moderate satisfaction, used chiefly when eating. Couiiiii (very pointed and repeated often) — cry of great satisfaction, food particularly delicate or not tasted for long time. Hem-hem (a cough and a heave, expressing ef- CPRESSIONS IN GIBBON 77 fort) — frequently when animal jumps from branch to branch. Kouhi-hig-hiig (with raising of hps and laugh of mouth) — great evidence of affection — tender salutations. 2. State of illness or fear. Houg, houc, oug, houc (mezzo voice) — ennui. Koc, kog-koug . . . hiiig (with manifestation of anger) — frank hostility. In presence of person displeasing or an enemy; often followed by song of excitation. Ook-okoug (grave and jerky) — danger, some- thing frightening or unknown; looking at dark corner in evening; seeing object or animal un- known. Crug-cruuug (pecuhar sound accomplished by grinding of teeth) — rare, incomprehensible. En- nui of solitude. Illness. 3. Intermediate state. Thwiiwwg (sweet and plaintive)— to call atten- tion of friendly person. "I am here." Ho o o ouguoug (plaintive and long) — salute to beloved person not seen for long. Tempted to interpret as a plaint or friendly reproach. Kuhig ouk — satisfaction after a play, or a pleasantry which goes too far. Preut, Pruut (with vibration of lips) — menace of play. (Only in young animals.) 4. State of great excitement. Great song of excitement, with roulade and trem- bling of lower jaw. Heard at great distances in wilds. Mentioned by Owen. (Always preceded by jumping and shaking. May last several min- utes.) (Boutan, 1913, pp. 31-33 ) The author observes that no vocal ex- pression for a state of astonishment was noticed, and he suspects that if such exists it has been confused with expressions of fear, since the animal is extremely timid. The sounds recorded are numerous. Bou- tan concludes that they have not the value of words, but instead represent vague no- tions or awareness of agreeable, disagree- able, and dangerous situations or events. He characterizes the vocal expressions as a pseudo-language. This investigator's most important con- clusion is that the vocal expressions of the white-cheeked gibbon are instinctive and practically independent of the experience or special training of the individual. He carefully guarded his subject from the vo- calizations of its species throughout the period of captivity and observed that when 78 A STUDY OF ANTHROPOID LIFE it first produced a call it was the cry char- acteristic of the species. In comment on this important conclusion Boutan says that his subject responded to her name, clearly expressed certain desires in action, but never produced new sounds or imitated the sounds of her human caretakers. The gib- bon, he says, does not characterize objects by sounds. The latter indicate only a state of feeling; not the precise nature of food, but only the degree of satisfaction caused by it. The cry of the white-handed gibbon is graphically described by Tickell who, pass- ing from consideration of habitat and gre- gariousness to vocalization, says: It is rare to see a solitary one; occasionally, however, an old male will stay apart from the flock, perched on the summit of some vast tree, whence his howls are heard for miles around. The forests which these animals inhabit, resound with their cries from sunrise to about 9 a.m. Their usual call may be thus rendered. u^oo a Tcroo a woo a- vrour oo u/oe/ The sounds varying from the deep notes of the adults to the sharp treble of the young ones. During these vocal efforts they appear to resort to the extreme summits of the loftiest trees, and to call to each other from distant parts of the jungle. After 9 or 10 a.m. they become silent and are engaged feeding on fruit, young leaves, buds, shoots and insects, for which they will occasion- ally come to the ground. (Tickell, 1865, pp. 196- 197.) Referring to the captive siamang which he had opportunity to observe on ship- board, Bennett states: The sounds he uttered were various : when pleased at a recognition of his friends, he would utter a peculiar squeaking, chirping note; when irritated, a hollow, barking noise was produced; but when very angry, and frightened, or when chastised, the loud guttural sounds of ra, ra, ra, invariably followed. When I approached him for the first time in the morning, he greeted me with his chirping notes, advancing his face at the same time, as if intended for the purpose of salutation; but I did not feel desirous of trying the experi- ment, as I knew these animals were not in the habit of kissing, and I well knew they were in the habit of biting. (Bennett, 1834, II, 154.) Citing Miiller as his authority, Huxley (1863, p. 27) says: All observers testify to the prodigious volume of voice possessed by these animals. According to the writer whom I have just cited, in one of them, the Siamang, "the voice is grave and penetrating, resembling the sounds goek, goek, goek, goek, goek ha ha ha ha haaaaa, and may easily be heard at a distance of half a league." While the cry is being uttered, the great membranous bag under the throat which communicates with the organ of voice, the so-called "lar^^ngeal sac,'' be- comes greatly distended, diminishing again when the creature relapses into silence. The vocalization of the siamang is most fully described by Welch: The voice of Symphalangus syndactylus is re- markable for the variety of cries, which follow rapidly one after another, and at least five sounds can be distinguished, with all of which the gular bag dilates. Anyone with their eyes shut would certainly think there was more than one animal in the cage. These cries are : — (1) The usual and loudest, best described by the words "woe, woe, woe," &c., repeated rapidly and for a variable number of times, sometimes forty or fifty. Judging from the deafening noise the animal made with the "woe woe" &c. on the first occasion I heard it, I should think it could be heard much further off than an adult H. hoolock, but unless one hears two adults shouting against one another, it is very difficult indeed to be cer- tain which of the two has the louder cry. (2) A gurgling noise, best described by the word "moo," drawn out over several seconds and sounding somewhat like a human being beginning to vomit. It follows rapidly after the "woe, woe, woe," &c., as a rule, and the gular bag dilates to the greatest size with this sound, occasionally reaching a diameter of nearly 8 inches. The "moo" is made mostly during inspiration. (3) What I can best describe as a wailing- shriek like the word "wair" shrieked out for twenty or thirty seconds and sometimes longer, the voice being alternately raised and lowered a little. It usually follows rapidly after the "woe, woe, woe," &c., and is about as often heard as no. 2 — the gurgling "moo." It is, however, louder than the "moo." (4) A "ho, ho, ho," &c., repeated, as a rule, four or five times. I have only heard it on a very few occasions and it is not nearly so loud as the previous three sounds. (5) A squeal somewhat resembling the noise made by some Eagles. This is as rare as the "ho, AFFECTIVITY AND ITS EXPRESSIONS IN GIBBON 79 ho, ho," &c., and not so loud as the first three sounds. When at rest the gular bag is black in sun- light and slightly wrinkled, but on dilatation it becomes dull red. In its walk S. syndactyhis is bipedal like Hylobates. (Welch, 191 1, pp. 357- 358.) Gibbon vocalization and speech, except for the work of Boutan, have been ob- served instead of studied. Indeed, no aspect of linguistic expression and intercommuni- cation has been investigated thoroughly. Conclusions, therefore, are definitely con- tra-indicated, whereas research is demanded as condition of progress. CHAPTER EIGHT RECEPTIVITY AND ADAPTIVITY IN GIBBON OF the three chapters in which we have chosen to arrange psychobio- logical data concerning gibbons, the first and second deal primarily with native, early appearing, or hereditary traits and capacities, whereas the third and present one considers chiefly nurtural influences, acquisitions, and adaptations. There is in- timate relation and overlapping, inasmuch as Nature and Nurture, ''instinct" and "intelligence," the racially given and the individually acquired are inseparable as- pects of biological process. Probably neither is more important in the life of the organ- ism than is the other, and it is only by the artificiality of classification that we are tempted to describe them separately and to compare them as though they might func- tion independently. The word "instinct" seldom appears in this book; the word "intelligence," except as quoted, almost as rarely. We have no horror of the terms, but we are convinced that it is more profit- able to deal specifically with the facts of behavior and experience than to hide our ignorance in general terms. In the chapter on natural history we at- tempted so to use essential facts of struc- ture and classification, habit and life his- tory as to present a picture of the daily free life of the gibbon. In that on affec- tivity and its expressions we similarly tried with the meager materials at hand to sketch the emotive life. Always chief em- phasis has been placed on behavior, al- though we have freely used subjective terms in order to increase intelligibility. As we see it, each of these chapters is pre- paratory to that on adaptivity, for the facts of natural history and of affective life bear intimate and significant relation to the nature and expressions of "intelli- gence." We purpose in this, the final chapter on the psychobiology of the gibbon, to gather together what is known of its environmen- tal relations and characteristic forms of adaptation, docility, or educability — terms which we may use interchangeably and without initial attempt at precise defini- tion. Interested rather in the modes, rates, limits, and relations of behavioral adapta- tion than in its presence orykbsence, we have arranged the facts accordingly.' "/ Belittling of our undertaking though it may seem, we must initially admit the sci- entific inadequacy of the materials which are available on the psychobiology of the gibbon. We are eager to point out defects and deficiencies because it seems an excel- lent way to stir effort toward more nearly accurate and adequate knowledge. For the natural history of the gibbon we discovered available materials to be meager and fragmentary. In no single direction can one tell with assurance a connected and de- tailed story of the daily life of this spryest and shyest of the apes. Even more dis- heartening are the data on affectivity and its modes of expressions. They are crude, incomplete, unreliable, merely glimpses through a clouded glass, and well-nigh valueless, we judge, except as they may arouse our ambition immeasurably to outdo our predecessors in quest of facts, insights, and vision. But whereas gibbon natural history and affectivity are in a prescientific stage of in- vestigation and descriptive examination, adaptivity has entered upon the obviously scientific phase by virtue of the systematic naturalistic and experimental studies of a single investigator, Louis Boutan. Descrip- tion of gibbon "intelligence" prior to the publications of Boutan is hopelessly crude and unconvincing. Happily, his contribu- tions constitute an outstanding excuse for an otherwise depressing recital. The situa- RECEPTIVITY AND ADAPTIVITY IN GIBBON tion which our study of the Hterature re- i vealed has made us feel that where sci- entific inquiry begins, ignorance is more favorable than misinformation, for the lat- ter implies bias, prejudice, preconception, ■ and the false assumption of knowledge. RECEPTIVITY THE MODES OF SENSE To the average user of this book we doubt- less shall be equally intelligible whether we employ the objective technical terms re- ceptor, effector, and reaction, or the sub- jective terms sense organ, organ of expres- sion, and sensory response. Either way there are implications a plenty, and as our knowledge of the train of psychobiological facts doubtless is nearer its beginning than its completion, we resolutely decline to label ourselves as objectivistic or subjec- tivistic. Instead we shall endeavor to be practical and pragmatic, thus satisfying neither extreme party, and we trust suffi- ciently irritating all to increase desire for information and understanding. It appears that the morphologists have devoted considerable attention to the nerv- ous system of the gibbon. Witness such ad- mirable structural studies as those of Flower (1863), Kohlbriigge (1890-91), Waldeyer (1891), and the invaluable di- gests and bibliographies of Keith (1896) and Sonntag (1924). "The brain in the Gib- bons," writes the latter, "is intermediate in its characters between those of the Cer- copithecidae, on the one hand, and those of the larger Simiidae on the other. Moreover it indicates in some ways the path pur- sued by the latter in evolution." (Sonntag, 1924, p. 282.) In what for the psychobiologist is by far the most illuminating and generally useful description of the gibbon brain in compari- son with that of other primates, Tilney (1928, I, 405 ff.) describes the configura- tion of the cerebral hemispheres as little more advanced in many respects than those .of baboon and rhesus monkey. The prin- cipal fissures and lobations agree closely. In some ways, according to this authority, the gibbon brain is more complex and 81 highly developed than that of the mon- keys; in other respects, somewhat less so. There is, Tilney writes: a richness of convolutional pattern in the oc- cipital lobe, which does not exist in either of the other two forms. This fact, taken in conjunction with the much reduced appearance of the su- perior colhculus of the midbrain, indicates that in the gibbon most of the actual supervision of vi- sion has been transferred to the occipital lobe. The fissures in the temporal lobe, especially the superior temporal fissure, are well developed and this latter has connected with its extremity a well- defined angular gyrus. The fissures of the basal surface of the frontal and temporal lobes give these regions an extremely simple appearance. In fact, the impression ob- tained from a survey of the cerebral hemispheres in gibbon alHes this form much more closely with the group here identified as intermediate pri- mates. Certainly, the superficial appearance of the gibbon's cerebral hemisphere places between it and the more highly complex endbrain of the great anthropoid apes a wide interval, so wide as to justify the opinion that in descent, the lineal rela- tion between the gibbon and the anthropoid, how- ever direct, must be quite remote. (I, 415-416.) Of the "sense organs" Sonntag (1924, pp. 314-316) remarks that tactile corpus- cles are present in the skin of apes and man; that the anthropoid eye, in its gen- eral anatomy and so far as examined, is similar to that of man; that the ear of apes also is essentially like the human ; and that other types of receptor which undoubtedly exist in each of the anthropoid apes have not been studied. We note, however, that Kunze (1915, pp. 651-659) has described the papillae of the tongue in gibbon and siamang. Evidently then structural neurology has little to offer relative to the receptivity or modes of sense in gibbons. This is a re- grettable situation which suitable provision for anthropoid research should presently alleviate. Aside from structural evidences of modes and characteristics of receptivity there are those from general behavior, but on search- ing the literature for pertinent data we dis- covered no reports of either naturalistic or experimental examination of any mode or aspect of sense. Even the conspicuously 82 A STUDY OF ANTHROPOID LIFE important special senses have not been surveyed, much less studied intensively and tJioroughly. And far more suq^rising and discouraging is the discovery that natural- istic or field observation of the animals has yielded almost no scientifically acceptable information. It appears then that the sensory anatomy and physiology, like the sensory psycho- biology, of this great family of apes are virtually untouched. Where we need estab- lished and well-correlated assemblages of fact appear chance observations, which are fragmentary, unverified, and often we fear unverifiable, inferences, opinions, and sur- mises. Combining what few established struc- tural and behavioral data the literature supplies as basis of tentative statement, it may be hazarded that vision, and hearing are highly developed modes of receptivity in the gibbon. Indeed, conditions of life suggest that hearing may be more acute than in most other primates; and the na- ture of its vocalization prepares us for dis- covery of a complexity of auditory recep- tivity comparable with that of man. Pocock, emphasizing the importance of acute hearing in the life of the gibbon, points to a structural character which he thinks may be indicative. "In this connec- tion it is important to note that of the two Apes inhabiting W. Africa, namely the Chimpanzee and the Gorilla, and of the two inhabiting the East Indies, namely, the Orang and the Gibbon, the larger and stronger has in each case small insignificant ears and the smaller and weaker large ears." (Pocock, 1905, p. 180.) Presumably this author refers to the external ear or possibly exclusively to the pinna. In either event the biological significance attributed to the structural differences appearing among the anthropoid apes is doubtful. Yet it may very well be true that the sense of hearing is more highly developed in gibbon and chimpanzee than in orang-outan, go- rilla, or even in man. Sonntag, referring to the same observa- tion and quoting Pocock, further remarks: "The external ears are most prominent in Man and the Chimpanzee, for they are concealed by the hairs in the Gibbons, Orang and Gorilla. Their small size in the Gorilla and Orang permits them to be easily hidden." (1924, p. 316.) In view of all that is known of the wild life of the gibbon, and especially of the nature and demands of its environment and its social relations, one might expect it to depend for avoidance of dangers and escape from aggression on the special senses of hearing and sight. Obviously it is adapted to quick flight instead of to defense or ag- gression. In this respect it contrasts most markedly with the gorilla. Although we should, for such reasons, expect gibbon vi- sion to be of an order of acuteness and complexity comparable with our own, avail- able data justify only the inference and not the assertion that the animals' amazingly accurate spatial adjustments are condi- tioned by visual data. Of the system of visual impressions and perceptions — color, brightness, form, size, distance — we are profoundly ignorant. The same degree of ignorance obtains for the other modes of sense. It is impossible even to list them; much less may we describe them. We would not leave the reader with the impression that there are no dogmatic as- sertions concerning the senses in the litera- ture on gibbons. As a fact there are a great many statements based upon casual observation or inference from what has been read. They apply, however, almost ex- clusively to sight and hearing. Of the cu- taneous, kinaesthetic, and chemical sense modes nothing apparently is known, and, strange to say, nothing is asserted. It is our opinion that these scattering, unsupported statements are negligible in value, and we have taken little pains to cite or otherwise give credit for them. One might, it is true, from knowledge of modes of sense in man and other pri- mates, and very general acquaintance with the natural history and behavior of gib- bons, write an interesting and perhaps also substantially correct general description of RECEPTIVITY AND ADAPTIVITY IN GIBBON 83 the receptive equipment of this family of apes. But it would obviously be of infer- ential instead of observational origin and profitless except as an intellectual exercise or as a species of prophecy, to be subjected to the test of experimental inquiry and measurement. "intelligence" Prior to the early years of the nineteenth century the adaptive behavior of gibbons seems to have escaped critical examination and remark, although it frequently at- tracted attention and provoked comment and characterization. It remained for Sir Thomas Stamford Raffles, during his gov- ernorship of Bencoolen, Sumatra, to arouse scientific interest in these apes by notable ] additions to naturalistic information. His efforts were partially robbed of their value by serious disagreement with the French naturalists Duvaucel and Diard, whom he had employed as assistants. Raffles himself I published little on the behavior of gibbons, 1 and the notes of Duvaucel were used by Cuvier in his natural history of mammals, 1 which by virtue of this unique contribution [becomes the most valuable of our early sources of light on the intelligence of the siamang and Hylobates. Referring to the siamang, Duvaucel writes: This species is very common in our forests [those, namely, in the neighborhood of Bencoolen in Sumatra], and I have had frequent oppor- tunities of observing it, as well in its wild state as in bondage. . . . These animals are slow and , heavy in their gait; they want confidence when they climb, and agility when they leap, so that they may be easily caught, when they can be surprised. But nature, in depriving them of the means of readily escaping danger, has endowed them with a vigilance which rarely fails them ; if they hear a noise which is strange to them, even though they be at a mile's distance, fright seizes them, and they immediately take flight. When surprised on the ground, however, they may be captured without resistance, being either over- whelmed with fear, or conscious of their weak- aess and the impossibility of escaping. At first, in- deed, they endeavor to avoid their pursuers by flight, and it is then that their awkwardness in this exercise is most apparent. Their body, too tall and heavy for their short slender thighs, in- clines forwards, and availing themselves of their long arms, as crutches, they thus advance by jerks, which resemble the hobbling of a lame man whom fear compels to make an extraordinary effort. (E. Geoffroy-Saint-Hilaire and F. Cuvier, 1824, Le Siamang, p. i.) This often quoted account of the be- havior of the siamang has been adversely criticized for reasons which will presently appear. Of the agile gibbon Duvaucel offers the following account: These apes, which live more frequently isolated in couples than in families, are the least common of those found here [in neighborhood of Ben- coolen], since for five or six Wouwous one may see a hundred siamangs. Very different from the latter in its surprising agihty, it escapes like a bird, and Hke a bird can only be shot, so to speak, flying; scarcely has it perceived the most distant approach of danger when it is already far off. Climbing rapidly to the tops of the trees, it there seizes the most flexible branches, and bal- ancing itself two or three times to secure its equipoise, and acquire a sufficient impetus, it thus springs successively, without effort as without fa- tigue, to a distance of forty feet. As a pet or domestic animal it exhibits no ex- traordinary faculty : it is less clumsy than the sia- mang, its shape is more slender, its movements are more prompt and graceful, but its manners are less lively than those of the monkeys; and in its long slender arms, in its short bandy legs, one is far from suspecting such vigorous muscles and such marvelous agility. Nature, however, has not bestowed upon it a large portion of intelhgence. In this respect it is in no way superior to the siamang, both are de- prived of high forehead; this is one of the great points of coincidence between the two species. What I have myself seen, however, convinces me that it is susceptible of some education; it has not the imperturbable apathy of the siamang; it may be frightened or pleased; it flies from dan- ger, and is sensible of good treatment; it is glut- tonous, curious, familiar, and sometimes even gay and lively. Though deprived of the guttural sac so remark- able in the siamang, its cry is very nearly the same; so that it would appear that this organ does not produce the effect ol increasing the sound usually attributed to it, or else, that it must be replaced in the present species by some analogous formation. (E. Geoffroy-Saint-Hilaire and F. Cuvier, 1824, Le Wouwou, p. 2.) Rennie (1838, p. 166) is authority for the statement that Raffles disagrees with 84 A STUDY OF ANTHROPOID LIFE Duvaucel in his characterization of the sia- manjr and estimate of its "intelligence," since he speaks of it as bold and powerful, but easily domesticated, and so sociable and affectionate that it is content only when in company with those to whom it is attached. Possibly this is fair to Raffles, but our search has discovered in his publi- cations only a few sentences relating to be- havior and they supply little and indefinite information. Unfortunately the notes and manuscripts of Raffles were destroyed by fire. In the same period with the work of Raffles, Duvaucel, Diard, and Horsfield in Sumatra, appeared the publications of Har- lan who in his meager notes on the behav- ior of a specimen of Bornean gibbon, H. concolor, ventures the assertion that this ape possesses "all the docility and intelli- gence characteristic of the orangs." (Har- lan, 1825, p. 230.) Presumably he was using orang in the inclusive sense to desig- nate both orang-outans and gibbons. If not, his guess certainly is far from correct since the orang-outan is undoubtedly far su- perior to the gibbons in adaptivity of be- havior. The following account by Bennett of the behavior of a young siamang is strikingly at variance with the statements of Duvau- cel: His look was grave, and manner mild, and he was deficient in those mischievous tricks so pe- culiar to the monkey tribe in general. In only one instance did I experience any mischief from him, and that was in his meddling with my inkstand: he seemed to have an extraordinary penchant for the black fluid — would drink the ink, (by placing his finger in the inkstand, and then sucking it,) and suck the pens, whenever an opportunity of- fered of gratifying this morbid propensity : his black coat did not suffer from his dabbling in ink, unlike many of the human species, who suf- fer both in constitution and apparel from med- dling too much with it. There was a degree of intelligence in the ani- mal, beyond what is usually termed common in- stinct. These little miniatures of men, (as they are satirically termed,) are said to possess more sagacity than other animals, and to be a close connecting link between the "powerful lord of the creation," and creatures of an inferior genus. If it be true, as I have heard asserted, that intelli- gence is written in legible characters on the os frontis of the monkey tribe, I beg to add, that mischief and cunning also beam in their eye. One instance of a very close approximation to, if it may not be considered absolutely an exercise of, the reasoning faculty, occurred in this animal. Once or twice I lectured him on taking away my soap continually from the washing-place, which he would remove, for his amusement, from that place, and leave it about the cabin. One morning I was writing, the ape being present in the cabin, when casting my eyes towards him, I saw the lit- tle fellow taking the soap. I watched him, without his perceiving that I did so ; and he occasionally would cast a furtive glance towards the place where I sat. I pretended to write ; he seeing me busily occupied, took the soap, and moved away with it in his paw. When he had walked half the length of the cabin, I spoke quietly, without frightening him. The instant he found I saw him, he walked back again, and deposited the soap nearly in the same place from whence he had taken it. There was certainly something more than instinct in that action : he evidently betrayed a consciousness of having done wrong, both by his first and last actions ; — and what is reason if that is not an exercise of it? When he walks in the erect posture, he turns the leg and foot outwards, which occasions him to have a waddling gait and to seem bovv-legsed. He would pace the deck, being held by his long arm; and then had a resemblance to a child just learning to step. The limbs, from their muscular and strong prehensile power, render the animal a fit inhabitant for the forest; enabling him to spring from tree to tree with an agility that we have frequently witnessed him display about the rigging of the ship : he would pass down the backstays, sometimes hanging by his hands, at others walking down them in the erect posture, like a rope-dancer, balancing himself by his long arms; or he would spring from one rope at a great distance to another, or would drop from one above to another below. Being aware of his inability to escape pursuit, when running on a level surface, his first object, when about to make an attack, was to secure a rope, and swing towards the object he was de- sirous of attacking; if defeated, he eluded pur- suit by climbing out of reach. He has an awkward manner of drinking, by which the hquid is much wasted: he first applies his lips to the liquid, throwing the head up, which in some degree may be attributed to the promi- nency of the lower jaw : and if the vessel in which the liquid is contained should be shallow, he dips the paw into it, and holding it over the mouth, lets the liquid drop in. I never observed him lap with the tongue when drinking; but when tea or coffee was given to him, the lingual organ was carefully protruded for the purpose of ascertain- RECEPTIVITY AND ADAPTIVITY IN GIBBON 85 ing its temperature. This display of caution was not confined to this species of ape, as I know of several others which will do the same, when hot tea or coffee is given to them; shaking their sapi- ent head violently, if they are heated by the liquid; but still, undeterred, will wait patiently until the hot liquid becomes sufficiently cool for bibulary purposes. (Bennett, 1834, II, 154-158.) The Bennett soap story is a stock anec- dote, indicative perhaps of certain charac- teristic mental traits of gibbons, but of very uncertain value to the critical student of psychobiological phenomena. On considering all of the facts presented by Duvaucel and Bennett in the light of our general knowledge of the structural characters and life history of the siamang, and of the relations of behavior to stage of development in the great apes and man, we have reached the conclusion that the de- scriptions are not necessarily inaccurate or contradictory, but that instead Duvaucel and Bennett may have observed accu- rately and adequately described the be- havior of differing specimens. Bennett, it is reasonably certain, studied an immature male which was characteristically friendly, lively, and docile. Duvaucel, with knowl- edge of many individuals, may have been influenced chiefly by the behavior of the mature, senile, or ill conditioned. We are inclined to agree with most other critics and commentators that Bennett's descrip- tion is more closely applicable to the be- havior of the average captive specimen than is that of Duvaucel; and we are con- vinced that the apparent discrepancies in their reports are due to incompleteness of description. Had they indicated sex, age, and physical condition as well as species, they would have supplied essential basis for comparison. Tickell, who otherwise contributes noth- ing of note to our knowledge of adaptivity, remarks that young gibbons which he ob- served in captivity were "generally feeble, ,dull, and querulous, sitting huddled upon the ground, and seldom or never climbing ^ trees." (Tickell, 1865, P- 198.) We quote i his statement because of its obvious im- portance for studies of behavior. Unless pains be taken to render conditions of cap- tivity favorable for these animals, their be- havior is almost certain to be unusual or abnormal and descriptions of it inapplica- ble to the species. An entirely secondhand account of what was then known of the adaptive behavior of the gibbon is presented by Figuier, whose pertinent conclusion is thus ex- pressed: "These Monkeys [gibbons] are the least intelligent of the group we are now examining: the structure and volume of their brain, as well as their actions while in a state of captivity, put this fact beyond a doubt. But it would not be just to say, as some naturalists have done, that they are destitute of all intellectual faculties. The results of experience are opposed to this assertion." (Figuier, 1870, p. 586.) And by contrast Garner (1900, p. 276) remarks: "The gibbon is the most active and probably the most intelligent of all apes." A bit of evidence not without value in connection with a study of gibbon "intelli- gence" has been provided by Candler, whose interesting observation unfortu- nately cannot be safely interpreted without critical reexamination and supplementa- tion. As, day after day, I have ridden through the jungle, it has seemed to me that the Hoolocks work their ground systematically in their search for food, just as the planter plucks one section of his tea to-day and another section on a distant part of the garden to-morrow. For I have found them filling the air with their cries along a par- ticular stretch of jungle-road one day, whilst the next day not one was to be heard; then, perhaps, a week later they are back again in the same place. Living as they do in communities, they are constantly on the move, and from what we know of their great intelligence, it seems to me highly probable that their movements are guided by very definite plans, and that very probably they have some sort of government system. (Candler, 1903, p. 188.) By P. Chalmers Mitchell (19 12, p. 209) the gibbon is ranked as less intelligent than the great apes, although of young speci- mens he says they "soon become docile and are always gentle and friendly. One of 86 A STUDY OF ANTHROPOID LIFE those now at the London Zoological Oar- dens has been taught to swing round and round a bar holding on by his hands, and to stop and reverse at the word of com- mand." The gibbons, according to Debeaupuis (1924, pp. 137-138), are adjudged from the structure and volume of the brain to be the least intelligent of the "anthropo- morphic monkeys." They are, however, ex- cellent observers, equipped with sharp eyes, and extremely alert and active they miss nothing. From the unpublished notes and manu- scripts of Doctor and Mrs. Spaeth we have already, and in other connections, quoted descriptions of gibbon behavior which indi- cate marked docility and the power of rapid adaptation during early life to condi- tions in captivity. Considerable importance must be at- tached to the well-established fact that captive gibbons seldom are trained to any kind of work or useful service, aside from the performance of simple tricks or acro- batic exercises. Their relative inaptitude for such training and for systematic labor may be referable in part to adaptivity and in part to affective traits. We have exhibited accounts of the in- telligence of gibbons rather for the sake of historical completeness and in order to in- dicate the natural development of knowl- edge than because of their scientific value. Indeed, it is evident that the scientific study of gibbon intelligence was not under- taken by any of the authorities thus far mentioned. We propose now, in contrast with the casual observational contributions, to present more general and systematic dis- cussions of intelligence. The earliest general descriptions of an- thropoid behavior, including that of the gibbons, continue in many respects the best available. They are the previously quoted Natural History of Monkeys, Opossums, and Lemurs, which we have attributed to Rennie (1838), and The Natural History of Mammiferous Animals by Martin (1841). The former we consider excellent as a summary account of the prescientific period of acquaintance with anthropoid apes, and the latter we value even more highly because the writer assumes a larger measure of responsibility for the coordina- tion and evaluation of his materials. Again we state that no one who wishes to fa- miliarize himself with the history of an- thropoid psychobiology can afford to neg- lect either of these natural histories. The publications of Forbes (1894), Keith (1896), Elliot (1913), Heck (1922), and Sonntag (1924), have values in this connection peculiar to themselves. In no in- stance are they comparable with the works of Rennie and Martin. What Forbes in his Handbook to the Primates offers on gibbon adaptivity is entirely incidental to taxo- nomic description. This is true also of the more extensive, but for the student of be- havior less convenient and less readable, work of Elliot. Keith has limited himself chiefly to summarizing and presenting im- portant references on the morphologv of the anthropoids, and Sonntag similarly specializes on morphological materials. The Tierleben of Brehm (Heck) admirably brings the accounts of Rennie and Martin to our times. It is readable, although often poorly arranged, and apparently fair and reliable. The only approach to a systematic criti- cal examination of gibbon "intelligence" of which we have know^ledge is that of Mahou- deau, who in an article of promising title devotes his attention almost exclusively to the seemingly contradictory^ observations of Duvaucel, Diard, Raffles, and Bennett. By way of introduction he points out that the gibbon is of particular interest and value as object of studv because recent paleontological discoveries indicate that it is an archaic form which perhaps possesses many characteristics similar to those of man's anthropoid ancestor. The encepha- lon, for example, is characterized as "primitive" and, therefore, capable of in- dicating to us characteristics of its struc- ture in primitive man. From the following quotation one gets a RECEPTIVITY AND ADAPTIVITY IN GIBBON 87 vivid impression of Mahoudeau's special interest in gibbon intelligence and his strong bias in favor of the unity of the animal kingdom. For Man is not, as was long believed, a privi- leged being, distinct and completely different from those living about him. The basic form of all his organs, as well as the primordial function of his intellectual center are found in the animals, par- ticularly in the monkeys and apes. Nothing then, constituting the organization of Man is distinctive, unless it be the degree of per- fection acquired by his cerebral centers, a perfec- tion which has resulted from an immensely long series of intellectual efforts on the part of his ancestors. Among the zoological specimens most closely related to the human form in anatomical charac- ter and in physiology, one deserves especial at- tention. Not because it seems at first glance to be so similar to Man; not at all, for because of its small size and arboreally-adapted members it seems to be much less human than nearly all the other Anthropoids; but because the remarkable remains of the great primate fossil unearthed at Java, the Pithecanthropus, have shown that the most inferior in evolutionary degree of all the Anthropoids, was the one which presented in best state of preservation, those traits which must have belonged to our distant ancestors when the human prototypes commenced to separate, to dif- ferentiate from their zoological collaterals. It is for that reason that were all the Anthro- poids capable of furnishing the most interesting documents toward the natural history of Man, only one of them could be considered as almost approximating the survival of a form having taken part in our genealogical creation, and, in this capacity, this Anthropoid is for us much more precious than all the others. This type of Anthropoid which is so archaic is the type Hylobatidae, comprising in the present epoch, many species called Gibbons living in the southern countries of the far East. . . . Being a very old form, the type Hylobatidae possesses naturally a very primitive encephalon capable in consequence, of giving an idea of what must have been in its rudimentary state the en- cephalon of our protohuman ancestors; for how- ever great may be the existing difference between the brain of the Hylobatidae and of Man, it is not a matter of structure so much as a matter of difference of degree of evolution. From these facts it results that the intellectual manifestations of the Gibbon ought to be very similar to those of pri- mordial Man, and ought therefore to procure for us information of inestimable value. Small and weak, the Gibbons, living in equa- torial forests, surrounded by enemies, in the midst of perpetual dangers, are very fearful, excessively cautious ; moreover, they derive all the advantages of living in bands composed oftentimes of a large number of individuals. Though certain species, such as the Gibbon Lar, are sometimes encoun- tered in a small group of not more than from five to twenty individuals, the Siamang Gibbons and the Houloks generally form troops of fifty and even of a hundred individuals. It is certain then, that the Gibbon is eminently sociable, and that the need of hving in a' society, the need to which our civiHzations owe their origin, is found well developed in the Gibbon; moreover, it is not im- possible that the beginning of human societies took place at a time when our ancestors were still being confused with those of the Hylobatidae. The intelligence of animals living in a society is necessarily more developed than that of zoologi- cal species which remain solitary; that of the Gibbons ought therefore from their social hfe to be as advanced as the rudimentary morphology of their brain will permit. It should not be for- gotten that representing the most archaic type among the Anthropoids, the Gibbons cannot pos- sess an intelligence similar to that of the Gorilla, the Orang, and the Chimpanzee, all much more evolved than they ; but the intellectual manifesta- tions of these primitive primates, whose cerebral morphology is much further removed from Man than any of his congeners, are for that very rea- son, much more instructive. (Mahoudeau, 1913a, pp. 365-367-) Relative to the discrepancies between the Duvaucel and Bennett descriptions of siamang behavior, Mahoudeau makes cer- tain acute observations. We permit him again to speak for himself. It is certain that from the point of view of mental manifestations there exist notable differ- ences among the diverse hylobatine species ; but if the Siamang is perhaps less lively, less intelligent than some of his congeners, he does not seem, however, to merit all of the disparaging epithets pronounced by Duvaucel and which are unjusti- fied not only according to the observations of other authors, but also according to some of those belonging to Duvaucel himself, which we will cite a little further along. But, first, a simple remark: this Siamang which in captivity is so insensible to favorable and to unfavorable treatment, which eats with such in- difference, and watches the removal of its food without interest, could it not be otherwise than an animal absolutely stupid, than a simple living mechanism ; for does it not rather give the im- pression of a being comprehending its pitiable situation and to whom captivity is so cruel as to render everything indifferent to him? The Gib- bon, an Anthropoid essentially gymnastic and arboreal, should be extremely miserable when his 88 A STUDY OF ANTHROPOID LIFE space and his freedom an- (urtailed; and then, who could assure us that the disagreeable cry uttered at intervals by Duvaucel's Siamanfi was not an unhapjiy exclamation, the despairin*^ cry of an unfortunate captive? The justice of Duvaucel's statements becomes very doubtful in face of the fact that generally the Gibbons observed in captivity have not been found so sleepy, so apathetic, so deprived of all intellectual faculty, so like living machines as Duvaucel pretends. (Mahoudeau, 1913a, p. 369.) Peculiarly apt and impressive is Mahou- deau s surmise that the siamang observed by Duvaucel may have been extremely de- pressed by captivity and resentful of it. The attitude of indifference may lead even the best of observers to mistake high levels of intelligence, insight, or comprehension for dulness and stupidity. Actually this is a frequent occurrence in the relations of man, as observer, to the anthropoid apes. EXPERIMENTAL STUDIES OF INTELLI- GENCE BY BOUTAN AND OTHERS The French zoologist, Louis Boutan, has the unusual distinction of first studying the behavior of the gibbon systematically and under carefully controlled conditions over a long period. Interested initially in forms of vocalization and their linguistic rela- tions and significance, he subsequently undertook an exploratory study of methods of adaptation of behavior. His report on pseudo-language in 19 13 and on methods of learning in 19 14 are pioneer experimen- tal studies in anthropoid behavior of out- standing importance, which somew^hat an- tedate the psychobiological studies of the chimpanzee by Teuber and Kohler and of the orang-outan by Yerkes. Neither of Boutan's publications has received its mer- ited degree of attention from physiologists and psychologists. The reports are not even listed in the extensive bibliographies of such important texts and handbooks as Wash- burn's The Animal Mind (1908, 191 7, 1926) ; Kafka's Handbuck der vergleichen- den Psychologie (1922), Hempelmann's Tierpsychologie (1926); and only the 1914 publication is listed in the Psychological Index. Yet these studies hold the same |)lace among publications on anthropoid "intelligence" that Thorndike's monograph on Animal Intelligence (1898) holds among experimental studies of mammals which in psychobiological development stand close to the primates. Explanation of this over- sight and neglect may be found in the titles and place of publication of Boutan's papers: "Le pseudo-langage" (1913) and "Les deux methodes de I'enfant" ( 1914) , both appear- ing in Actes de la Societe Linneenne de Bordeaux. In the previous chapter Boutan's obser- vations on vocalization in the gibbon have been described and his more important re- sults and conclusions epitomized. Thus we have endeavored to exhibit and to empha- size the scientific significance of studies which appear to be of quite extraordinary- interest and importance. Naturally after more than a decade of rapid progress in the experimental investigation of problems of behavior, the technique and method- ology of Boutan, like those of Thorndike, seem crude and inadequate. Supplementing the content of our previous chapter, as far as the Boutan studies are concerned, we shall now draw primarily upon the content of his second report which is devoted ex- clusively to adaptations of behavior, and we shall cite from the report on pseudo- language only certain observations which are indicative of adaptive capacity. During a brief visit to Haut-laos, Indo- China, Boutan was enabled to obtain a very young female specimen of the white- cheeked gibbon, H. leucogenys, whose mother had just been killed bv a hunter (Boutan, 1913, p. 43). This little creature was eventually taken to France bv the Boutans and reared with care and particu- lar attention to conditions of life and ex- perience as related to psychobiological ob- servations. It is stated in the 19 14 report that the animal had been under observation for five consecutive years. Of its ultimate fate we are ignorant. This anthropoid sub- ject is almost unique among specimens which have been used for experimental in- vestigations of behavior, for its life history RECEPTIVITY AND ADAPTIVITY IN GIBBON 89 Fig. 40. Pepee, the white-cheeked gibbon st Societe Linneenne de Bordeaux. is intimately known by the scientific ob- server almost from birth, and, still more important, its mode of life and experience are matters of record. The date of birth is lacking and consequently the exact age, but this is of decidedly minor importance as the age may be estimated to within a few weeks, and knowledge of life history and especially of experience during captivity is hhfil l/\ I. ..111. II,. ( nmlt-,.\ .11 L. Ih. Ill, 111 ,111.! a prime essential for the safe analysis, de- scription, and interpretation of adaptations in behavior. With this unique anthropoid subject, and under conditions unusually fa- vorable for observation, Boutan conducted his sustained investigation of certain funda- mentally important problems in behavioral expression and adaptation. From the report on pseudo-language, 90 A STUDY OF ANTHROPOID LIFE two |)riiici[)al lines of evidence bearin^^ on "intelligence" may be drawn. They con- cern phenomena of imitation and neural fatigue. In addition to the typical call and other vocal expressions of her species, Bou- tan's gibbon exhibited certain spontane- ously acquired vocalizations which it is as- serted were not imitations of the sounds made by other animals. Boutan states that she did not imitate any human sound, how- ever clearly pronounced before her. This, in view of the long period of continuous and intimate association of the ape with people, is a result important in itself which indicates either negativeness in the ape or actual inability to imitate human sounds. As we shall have occasion to remark in other connections, the total behavior of the anthropoid apes in situations involving hu- man vocal copy for imitative response is such as strongly to suggest negativeness, or, as Boutan himself expresses it, "refusal" to imitate, and the seemingly superstitious inference of the natives of the African and Indian regions that the animals, dreading to be put to work if they "talk," stub- bornly maintain silence! This surmise may not be as ridiculous as it first seems. Contrasted with the negative findings of Boutan on imitation of sounds by the gib- bon is the statement by Mott that a sia- mang held as laboratory subject imitated sounds made by dogs and guinea pigs (Mott, 1924, p. 1 161). In this case neither conditions of observation nor responses are described in sufficient detail to render pos- sible critical evaluation of the observations as opposed to those of Boutan. Tenta- tively we may conclude from the scanty evidences that the white-cheeked gibbon, at least, does not readily imitate sounds pro- duced by man, whereas under certain con- ditions the siamang may imitate certain animal vocalizations. Boutan considers the gibbon's larynx capable of varied sound production, but habitually treating sounds as "dangerous," "advantageous," and "indifferent," the ape attends only to such auditory stimuli as naturally interest it. It manifests no inter- est in music, having satisfied its curiosity concerning the source, or in human con- versation. When its attention is strongly held by compelling visual or auditory stimuli, or problems demanding some novel adjustment, as the price of a much desired reward, fatigue rapidly appears. The image of herself in a mirror, oscillated complexly, at first greatly excited Boutan's gibbon. vShe attempted to seize the other animal behind the glass, was visibly surprised by her failure, and presently yawned slowly, stretched out on the grass before the mir- ror, and went to sleep. There was no per- sistent endeavor to locate the imaged animal. Instead, according to Boutan, his subject quickly perceived the futility of her efforts and became indifferent. Evidences of neural fatigue (often called mental) and of interest in the mirror im- age, comparable with Boutan's, will be re- ported in subsequent chapters also for other types of anthropoid ape. Undoubt- edly the facts are of considerable impor- tance, and although much might be said of them speculatively, there can be no doubt that accumulation of observational data will more rapidly advance knowledge and understanding of relations to the psycho- biological system of the ape. The reports of Boutan are brief and his style almost laconic. One must read and re- read them in order properly to appreciate observations, interpretations, and reflec- tions. The following sentences, with which an important chapter concludes, we quote in translation primarily to exhibit the au- thor's habit of thought and expression: 'Ts it really a necessity for the animal to save its attention? If so, the possibility of learn- ing to speak would depend less on the total development of the nervous centers than on the resistance of the animal to an effort of attention." (Boutan, 1913, p. 57.) Turning our attention now to the second of the reports, which is a comparative study of adaptation in the gibbon and in young children, we shall endeavor to pre- sent with reasonable detail and adequacy the essential features of method, result, and RECEPTIVITY AND ADAPTIVITY IN GIBBON 91 conclusion. Our reasons for extended ac- count of this study are, first, its uniqueness as the first and only experimental examina- tion of gibbon intelligence, and, second, its importance. The author shall state for himself the general conditions of observation and his objectives. I have brought up for five consecutive years an anthropoid belonging to the genus Hylobates. It was isolated from other animals of its species and subjected to no training except that necessary in living with human beings. It learned to sit on a chair at a table and to eat with a spoon. I sub- jected it to certain experiments to see of what it was capable by itself and compared its actions with those of young infants under the same con- ditions. I used children young enough not to have language at their disposal and also children who had the use of language. Experiments were simi- lar to those of Thorndike, Kinnaman and other American authors. . . . The instruments which I used, boxes with bolts and boxes with cords, were of the same order as those of Thorndike and Kinnaman. Thorndike shut his animals into the boxes; Kinnaman, and I followed his method, left the animals at liberty where they might open the boxes. My predecessors used hunger as a stimulant ; I used appetite and desire for dainty food. ... I was unfortunate in having only one subject to use. I confined myself to determining the behavior of the animal left to its own re- sources in face of a given mechanism. The point in which my researches differ from the preceding ones I have mentioned is my comparison with children placed under the same conditions. It is impossible to penetrate directly into the con- sciousness of an anthropoid. We can only judge of his psychological work by exterior manifesta- tions. Indirectly we can present the same prob- lems to a child whose definite stage of develop- ment we know. The child differs from the man, but the man has been a child. One may use the acts of a child in order to appreciate those of an animal. Many such experiments are needed in order to arrive at precision and to furnish a solid base for the conclusions of the philosophers. (Boutan, 1914, pp. 3-7.) For the study of problem solution under experimental conditions two small com- municating rooms were employed: the one painted yellow served as the subject's workroom; the other, painted black, as the observer's room. The former was well lighted by daylight, the latter was dark except for artificial illumination especially manipulated for purposes of graphic or photographic recording of responses. The wall between these rooms contained two openings: one, closed by colored glass to exclude actinic light, and the other by a slide which could be operated when it was desired to take photographs of the subject. The observer could readily watch the ani- mal, whereas he could not be seen by it. The illumination of the subject's room was supplemented for photographic purposes by a gas lamp. The apparatus for manipu- lation by the gibbon was fastened securely to a table in the experiment room and so placed that the essential portions of the mechanism faced the observation window. With the experimental situation in readi- ness, the gibbon was taken into the experi- ment room in a covered basket by a labora- tory assistant, who, placing the basket on the floor, counted "three" distinctly, as sig- nal for the experimenter, unfastened the cover of the basket and retiring from the room closed and fastened the door. Thus the animal was set at liberty in its work- room without the possibility of influence by the experimenter and without knowl- edge of his presence as observer. The apparatus employed by Boutan un- doubtedly was suggested by his knowledge of devices used by Thorndike in his study of "associative processes" in the cat and by Kinnaman in his similar study of the be- havior of monkeys. The mechanical devices were extremely simple and obviously de- signed with a view to exhibiting methods of solution of novel problems. Two types of apparatus were employed: the one de- pending upon visible mechanisms, and the other upon hidden mechanisms. In all cases the apparatus consisted of a wooden box, 25 by 35 by 20 centimeters, either one or two sides of which were covered with wire netting instead of doors so that food placed in the box might readily be seen by the subject. A small hinged door in the top of the box when opened gave the animal di- rect access to the reward or lure. This door was fastened in the various experiments by more or less complex visible or invisible Fig. 41. Boutan experiment boxes, A, B, D, E, redrawn from Boutan, 1914, pp. 15-17. Courtesy L. Boutan and Societe Linneenne de Bordeaux. mechanisms, and the appropriate manipu- lation of these mechanisms constituted the required adaptation of behavior to the ex- perimental situation. For the first type of problem, that with visible mechanisms, four similar boxes were used. In the first, box a, the hinged door at the top of the box with wooden button on the outside by which it could be pulled open, was left unfastened; in the second, box b, a horizontally moving piv- oted wooden bar served to prevent the opening of the door until the bar had been pulled to one side; in the third, box c, the door was held shut by two such wooden bars which worked in opposite directions, and in the fourth, box d, there were three such bars. Essential features in the con- struction of these problem boxes appear in the accompanying illustrations. The apparatus with hidden mechanism consisted of a box like that already de- scribed, the hinged door of which was held in place by a bar within the box, invisible from without, and in addition a spring was so arranged that the door opened as soon as the bar was withdrawn. On one of the vertical sides of the box was fastened a tube in the form of a crook through which a light wire passed from one end of the RECEPTIVITY AND ADAPTIVITY IN GIBBON bar to a wooden knob on the opposite and more remote end of the tube. A slight pull of the knob caused the door to spring open. Following his description of this experi- mental apparatus, Boutan cleverly re- marks: "One may criticize these instru- ments as being childish, but I reply that is exactly my purpose, a study of a bit of childish work." (Boutan, 1914, p. 18.) Had he been inclined to verbosity he might have added that in so far as the apparatus was appropriate to the human adult, it was in- appropriate to the human infant, child, or anthropoid ape. In the following condensation of Bou- tan's account of observations and conclu- sions we have quoted only portions liter- ally translated. The remainder is free translation, paraphrase, or presentation of essentials in our own language. In her first experience on June 6, 19 10, in the box a experiment, the gibbon Pepee hesitated a moment after the basket was uncovered, then sprang to the table, dis- covered the lure (bananas) in the problem box, and gave her characteristic cry of satisfaction. She fumbled at the netting on the one side of the box, then on the other, trying to push her hands through the mesh. Then she examined the top (solid face) of the box, and noting the button, grasped it and opening the door seized a banana and ate it. The problem obviously was an ex- tremely simple and easy one. When confronted with the box b prob- lem, Pepee promptly jumped to the table, examined the lure, and attempted to open the door with the button. Prevented by the sliding bar or lever, she tried to lift the lat- ter in the same manner as she pulled the button. Checked in this she again grasped the button ; checked here also she returned to the bar, pushed it laterally, opened the door and obtained her reward. Boutan notes that the pushing of the bar appeared to be accidental. In her first experience with the box c problem, the gibbon examined the new ar- rangement of bars for several seconds. She then pushed bar i laterally without at- tempting to raise it and without touching the button. Turning her attention to bar 2 she pushed it and simultaneously jumped from the table. Returning she opened the door. The immediate repetition of this ex- periment convinced the observer that the gibbon now moved the bars horizontally without attempt to raise them. When this same problem was presented after an interval of three days Pepee pushed bar i so vigorously that it sprang back to its original position. Again she pushed it, then moved bar 2 and opened the lid. When box d with its three bars was pre- sented, Pepee pushed them in the order 3, I, 2. Bar 2 had been pushed so far that it prevented the opening of the door. Without appearance of astonishment the animal pushed bar 3 back part way, then moved bar 2, and presently succeeded in opening the door. Boutan considers significant the fact that in this trial she first attacked bar 3, the one new to her, and then worked successively bars i and 2. In subsequent trials the box was fitted with stops to limit the action of the bars, and Pepee, using both hands, quickly and without hesitation operated them success- fully. The experimenter points out that evalua- tion of these results necessitates critical consideration of three groups of factors: (i) the gibbon's prior experience with more or less similar objects; (2) the influ- ence of the observer on the animal during the period of work; and (3) the new acqui- sitions or experiences of the subject during experiments. It is stated that Pepee had certain familiarity with boxes and pack- ages as possible containers of food and would remove covers or pull off strings in order to get at the contents. Whether she acquired this ability through imitation or by independent trial is not definitely known. The influence of the observer was limited, Boutan believes, to the provision of conditions favorable for work. He was invisible to the subject during period of experimentation. Of new acquisitions there 94 A STUDY OF ANTHROPOID LIFE appeared to be several, as the investigator thus indicates. In her first experience with box b, single bar, Pepee found herself be- fore a mechanism which she did not know how to work. She tried to lift it like the button . . . went back to the button . . . returned to the bar. . . . Has she learned from the very first that to open a box the bar must be pushed horizontally and not vertically? . . . The fifth experiment shows this without doubt. . . . This notion is an acquisition of the animal, as we prove by the sixth and seventh experiments where the difficulty becomes much greater. One could even believe that she generalizes her discovery (which I do not believe) since she applies it immediately to any bar. . . . However that may be it remains that from these first experiments with the boxes and bars the anthropoid by her own means has ac- quired the notion that one may formulate thus: "To push the bar or the bars in a definite direc- tion opens the box and permits one to take the food." Since Pepee, like other animals of her spe- cies, has no word of language at her disposal, the notion in question cannot itself be formulated so clearly in her head. It seems that she might for- mulate it as a series of associated images at once visual, motor and tactile : the image of the object of which she wishes to get possession, the image of the cover which she must open, the image of the bar which she must push a certain way. I re- call what I have already written on pseudo-lan- guage: The ape is a talented mimic, but it is not a man. It can unconsciously play before us a panto- mime. It revives the various impressions of the external world; it has relatively extensive asso- ciations, a remarkable physical sensibihty, a true aptitude in translating through the play of fea- tures its impressions, painful and agreeable. It does not react with the automatism of the hen. It is a talented actor, but like the dog an actor whose rudimentary thought does not formulate itself in its head as in the case of the human actor by the aid of words, but by the aid of sensory images. The anthropoid has at the same time made an- other discovery which one is tempted to trans- late thus in human language. When she is carried into the experiment room the aid has counted in a loud voice i, 2, 3, and closed the door; the bas- ket is no longer closed and she may go out freely by raising the cover. This is a new experience; a new discovery which she does not formulate with the clearness of my interpretative phrases, for the same reason — absence of words. It is however present in the head of a Pepee as a series of audi- tory associated images whose ensemble consti- tutes a new notion. This is not the moment to examine how the anthropoid has acquired these new notions. Let us only agree that they are ac- rjuired by its own means. This knowledge repre- sents the definitive acquisition of the animal. It has no need, as in training, to pass from the con- scious to the unconscious, and the act which it performs in the first series of experiments is not repeated sufficiently to take on the value of an automatic act. (Boutan, 1914, pp. 29-32.) Passing now to consideration of the problem of an invisible mechanism — hid- den bar and spring — presented by box e, it would seem that anvthing resembling in- sight or understanding of the relations of the mechanism, to the end to be achieved by working it, was rendered impossible by the construction of the apparatus. Invisible fastenings, like many sorts of puzzle fa- miliar to human subjects, invite, if thev do not actually necessitate, fumbling, blind trial, and resultant accidental or chance solution of the problem and adaptation to the situation. But what, it is pertinent to inquire, happened in Boutan 's experiments with the gibbon? Initially the experimenter misjudged the effort and attitude of his subject, for the apparatus did not work with sufficient ease and was badly controlled. The reader will recall that in this prob- lem success depended upon the pulling of a wooden knob attached to the end of a wire which passed through a metal tube to a bar on the inside of the box. As originallv presented the mechanism required a pull of three kilos for release of the door. Pepee, on her first meeting with this problem box. looked at the food, seemingly noted the absence of the bars outside the box. at- tempted to open the door, walked around the box, with a finger traced the outline of the door and tried to pry it open, looked at the cord from which hung a weight of one kilo, touched it lightly with her fingers, returned to the box and then played about the room. Then for some time she alter- nately examined the box and played in other parts of the room. She tried to open the door with her teeth, but failed. The ob- server, deciding that the animal would have succeeded in solving the problem had the mechanism been sufficiently sensitive, dis- RECEPTIVITY AND ADAPTIVITY IN GIBBON 95 continued the experiment, and for subse- quent trials modified it so that a slight pull would cause the lever to move. In the next trial the gibbon carefully in- spected the box for several seconds without trying to open it, then played about the room, looked at the cord, tapped a card at- tached near the end of the cord to attract attention, and grasping the knob pulled it. The box opened with a crash and the ani- mal, startled, jumped to the ground. Later she returned and took the food. There fol- lowed several repetitions of the experiment in which the box was opened successfully by manipulation of the cord, but each time the opening of the door startled Pepee, and because of this she seemed to vacillate be- tween conflicting impulses: desire to get the food and fear of provoking a startling occurrence. Although one may consider the appara- tus for this experiment defective, even defects sometimes have values, and it is possible that in this instance more was re- vealed to the observer by the inadequately controlled problem box than would other- wise have been the case. For a later series of experiments box e was so modified that the mechanism worked easily and without noise, but the gibbon only very gradually lost her fear of the ap- paratus and during many experiments she hesitated to touch the knob. Finally, how- ever, she achieved sufficient confidence to solve the problem directly. The following description is typical as indicating the in- hibitory influence of her initial startling experience. In a trial relatively late in the series, Pepee jumped upon the table, looked at the cord, passed around the box and hung from the pipe [above the box]. This was a gymnastic figure which one calls a "drapeauy From as far away as she could get she struck the cord softly so that it did not open. She again explored the box for a new open- ing. This occurred several times. Finally she hung from the pipe, made a drapeau and at a distance touched the cord and opened the box. This experi- ment with an animal already fatigued by preced- ing experiments and not hungry is interesting. It seems to prove that the animal knew she could open the box but visibly was deterred by the phenomenon which had strongly impressed her in the preceding experiments. (Pp. 38-39.) For yet another series of experiments with box e the position of the apparatus was shifted, but the gibbon quickly be- came familiar with the altered situation and adapted perfectly to it. Apparently the spatial relations of the box in the experi- ment room only slightly influenced her adapted behavior. As Boutan says of this experiment: The result is that Pepee has made a new dis- covery which one may state thus: By pulling the handle the box is made to open and one can get food. After a time on account of the mistake with the apparatus Pepee acquired another notion. To touch the handle produces a startling and danger- ous phenomenon. This notion was little by little erased and there remained finally the essential dis- covery : Touch the handle, the box opens and one may eat the food. (Pp. 40-41.) At this point work was interrupted for a period of approximately three months, dur- ing which Pepee was taken to the country and permitted to rest. When returned to the laboratory her memory for the solution of the box problems was tested by the pres- entation of box d with its three bars. When given opportunity, the gibbon jumped to the table and with a single movement of her hand pushed bar 3, then in turn bars 2 and I. She worked without hesitation. Immediately following the test with box d, box e with its invisible mechanism was presented. Pepee unhesitatingly mounted the table, inspected the box quickly and without attempt to open it, looked at the handle, grasped the pipe and pulled the knob by stretching her arm. The experi- menter concludes that the new acquisitions achieved by Pepee in these experiments were perfectly preserved over a period of three months. Discussing his observational data, Bou- tan asserts that the gibbon learned certain things, or, as he put it, acquired certain new notions, from contact with the experi- mental situation and without training or tuition. In some instances the perception of relation between a given act and the open- 96 A STUDY OF ANTHROPOID LIFE ing of the box does not result from a single experience, and the animal may have to have several opportunities to manipulate the apparatus before it comes to work deftly, directly, and without hesitation. But [says BoutanJ, that connection once estab- lished is fixed abruptly and would give graphically a straight line from that moment. If the notion has need of some touching up in order to become definitive, it grows precise too rapidly, too sud- denly for one to say that the animal has con- tracted a habit. I wish to emphasize this point: that these new notions are too rapidly registered to be considered acquired habits. They are the notions of instruction and not of education. (P. 43.) It seems then that Boutan discovered from his observation of the gibbon what was revealed to Kohler in his experimental study of the chimpanzee and to Yerkes in his work with the orang-outan; namely, sudden or immediate adaptation. It is interesting to note that these observers, working independently and without knowl- edge of one another's results or conclusions, and each biased by Thorndike's descrip- tions of method of problem solution in the cat in favor of the accidental or trial and error solution of novel problems, made strikingly similar observations and arrived at conclusions which are almost identical. The phenomena observed by these sev- eral investigators were so obviously excep- tions to Thorndike's description that each evidently was at once impressed with the suspicion that in the anthropoid apes at least there is another mode of adaptation than that of trial and the elimination of useless movements. Boutan refers to this other method of adaptation in the gib- bon as learning with voluntary attention; Kohler, in the chimpanzee, as problem so- lution with insight, and Yerkes, in the orang-outan, as ideational behavior. The reenforcing character of these several ac- counts of anthropoid adaptation is particu- larly worthy of note. The early experiments with Pepee re- vealed her visible desire for the bananas in the problem box. She tried to obtain them, but this does not necessarily indi- cate com|)ari.son, juflgment, or reflection. It may be only the expression of impulse. Ap- plying the pronouncements of different psychologists to her behavior Boutan re- marks: A psychologist like Romanes or Morgan, who admits in animals a consciousness somewhat hu- man, will say : in Pepee, under the influence of the desire to take the food, there awakens on sight of the food the representation of the neces- sary act to raise the cover and introduce the hand, the image of the raised cover, the image of the execution and that of the movements nec- essary to accomplish it. Naturalists like Thorndike and Kinnaman would say : in Pepee, under the influence of the need to take nourishment, awake suddenly the movements which permit her to take food; the need of taking food brings about im- mediately the observed movements which are bound up intimately with kinaesthetic sensations. There is not then for the latter authors the inde- pendent representation of the necessary act and above all the independent image of its execution. I do not beheve that the ape, with a cerebral development inferior to that of man, deprived of speech, associates images in a consciousness some- what human as Romanes and Morgan seem to admit. Perhaps, however, Thorndike and Kinna- man grant too Httle to the mental power of the animal, and obviously the psychologists cited above grant too much. (P. 46.) Throughout the experiments the disap- piearance of useless movements was ob- served, but according to Boutan's descrip- tion and interpretation, the elimination instead of being gradual is immediately achieved and persistent. In the third experiment, Pepee. placed in the presence of a button which she knew how to work, of a sHde which she did not know, sought to raise the button. It resisted. If she reasoned as a child of the right age, she ought to . have been astonished at not seeing the box open as it had previously. In reality, she passed at once to the slide, then returned to the button, and then to the slide, without astonishment. It is nevertheless re- markable that she limited her efforts to the hut- ton and to the slide. ... In the fourth experi- ment also Pepee localized her efforts between the slide and the button. . . . Does it not seem as if her movements were oriented with a certain intui- tion of the end to be attained? That is not yei quite plain ; let us continue examining the experi- ments. The eighth, for example. Pepee the same day had familiarized herself (experiment 6) with the box of two slides. . . . The experiment re- peated immediately, she behaved thus : jumped RECEPTIVITY AND ADAPTIVITY IN GIBBON upon the table, examined slide i and the button without touching them, went around the box and examined the banana, came back to the front and regarded the two slides and the button without touching them ; suddenly she grasped the gas pipe and did her exercises for a minute, came back and around the box to the front and pushed shde i horizontally; unsuccessful; back to the pipe; later again examined the box, stretched her arm towards shde 2, pushed it and opened the box. With a little imagination and placing in the body of Pepee a human consciousness, it is curious to think what one could deduce from this short scene, as a manifestation of mental hfe. I con- clude, only, that Pepee, not being hungry that day, dissociated under our eyes the different im- pulses to act, and without seeing in these acts ex- amples of reason, it seems to me difficult to affirm that Pepee had only movements connected with kinaesthetic sensations and that she did not have a representation of the necessary act and an independent image of its execution. (Pp. 47-49-) Her behavior seemed to indicate that Pepee after a few experiences with each problem box acquired confidence in her abihty to secure the desired reward, and often, instead of working immediately and directly for it, examined the apparatus, played with it, hesitated, and gave atten- tion to other objects about her. The point is thus illustrated. Confronted with box e, Pepee executed a number of acts without obvious determination to work the mecha- nism. Then Suddenly the game ceases. She goes back to the box and after various useless efforts seizes the box with her two arms and tries to detach it from the table. . . . She approaches the handle, touches it, goes back to play; later she tries to pry up the cover with her finger. Afterward she lies down upon the box and plays with the spring which closes the door. I put in italics the point which seems to me most interesting in this long manoeuver. The animal who has used in turn her finger to pry it up, her arms to tear away the box, her teeth to gnaw the spring — does she not show us that she sees the precise end (the open box), independently of a certain movement bound up with kinaesthetic sensations? Here we dissoci- ate the movements and the idea of opening the box which provoked successively these different manifestations. There is there, if not the first sketch of a veri- table reasoning, at least an embryo of judgment. The animal seems clearly to react by a series of movements appropriate to an end, pursued under an influence of an idea. In using successively her finger, her arms, her teeth, our animal shows by a series of attempts that she possesses, up to a cer- tain point, a faculty of understanding which per- mits comparison, very elementary in kind. These movements appropriate to an end, without being the movements of reason in the human fashion, are not comparable only with those which Thorn- dike had noticed in the cats. . . . They are, on the contrary, comparable with those which Kinna- man has described with the Macacus rhesus, when that monkey, having failed to work a lock with its hands, tried to open it with its teeth. One cannot a priori, classify all mammals by the formation of their associations, although for the dog and the cat the severe conclusion of Thorndike is perhaps justified. We must admit that it is not the same with the primates and that one finds with them indications of a higher psychological life. This life is shown particularly in the eighth experiment. Pepee opens the box with the three slides. Curiously she begins with shde 3 which she has not used before. . . . Does she then generalize and formulate in her mind somewhat thus : a slide must be moved horizontally? I do not believe it. It seems to me more logical, given the development of the nerv- ous centers of the anthropoid and its powerless- ness to use a true language, even a rudimentary one, to admit that her indefiniteness in the choice of slides does not hold a power of generalization, but on the contrary a lack of precision. Pepee is in the psychological state of a young child who commences to talk and who calls "cheval" all the animals which resemble a horse. The child makes a generalization by ignorance. It has nevertheless its source in a comparison partial and clumsy. The child excels Pepee in having a word for the comparison, but it is not less true that Pepee has the possibility of a comparison and that her movements are directed by an idea. (Pp. 50-52.) Certain experimental studies of mam- mals other than the primates have revealed varied modes of attack on problems, a ver- satility of action which suggests, although it does not necessarily employ, ideational experience. This fact in adaptive behavior some have considered troublesome to those objectivists who would exclude mental fac- tors from their descriptions. But [remarks Boutan], troublesome or not, it seems to me established in the experiments I have just analyzed and it seems to me difficult to inter- pret otherwise the manifestations of my anthro- poid. In experiments 20 and 21, the use of idea and elementary judgment seem to me extremely clear, and especially, ordinarily, in the normal work of the anthropoid, the discovery of the necessary movement is due to simple chance and A STUDY OF ANTHROPOID LIFE 98 the mind of the animal does not seem to inter- vene except by vague and unprecise direction. One is able to have an idea, when one is an an- thropoid, without thereby being a Newton or a Descartes as to method and if the series of experi- ments reveals to us the possibility for the anthro- poid of making a judgment and perhaps even embryonic reasoning, yet Pepce certainly does not use reason to direct her work. It is not without hesitation and long reflection that I have arrived at that conclusion. Let us ex- amine her method of work. In the first experi- ments the animal touches tentatively without in- sisting, passes from button to slide, from slide to button. She registers the precious remembrance of a successful attempt, not the start of her discov- ery. She knows only in large that the operation of the slide brings about the opening of the box, and she does not know precisely at first the exact di- rection, to right or left, in which to give the push. If the slide resists on one side, she pushes it from the other. In spite of all, when the animal works the boxes with the visible mechanism we must ask if she does not truly reason more than we think in order to bring about the correct movements. It is not quite the same with box e. There we see the animal touch the cord and open the box when not a single reasoning judgment or comparison could guide her or indicate that that cord com- manded the opening. We must acknowledge that her method is based solely upon trials, and they are fixed under the influence of awakened atten- tion. Awakened attention does not seem to me to have struck Thorndike and Kinnaman sufficiently. It explains, I think, the progress in the move- ments towards an end and the abandonment of useless movements without the intervention of reason. It seems to me to play so important a role that I shall devote the following chapter en- tirely to it. To summarize, Pepee effects her movements without a clear pre-visian of the act which ac- complishes the opening of the box. We may infer that she has a vague idea of the movements which conduct to that end. Her attention, excited by the presence of agreeable food, allows her to re- member a useful movement. The idea that an ap- propriate movement can open the box is then with her passive and ncft directive. I have there- fore adopted an intermediate opinion between those mentioned above. With Thorndike, Kinna- man and the naturalists I believe there is not clear pre-vision of the movement to be accomplished; but I believe at the same time there is pre-vision of the end to be attained. With Morgan and the psychologists of the same school, I believe that in the consciousness of the animal the idea of move- ments is independent of the movement itself ; but I depart from them in believing that the idea is passive and not directive of the movements. (Pp. 53-5S-) In his chapter on attention Boutan dis- tinguishes two types which he designates as natural or spontaneous and artificial or voluntary. The former is commonly ob- served in all mammals, whereas the latter is characteristic of man. Indeed, Boutan goes so far as to speak of the former as animal attention and of the latter as hu- man. This distinction is similar to one I have made between pseudo-language and language. Pseudo- language and animal attention both exist with animals and man ; artificial attention is a human attention. Artificial attention develops truly only when man has conquered, as an instrument, words. With the primates, whose nervous centers approach those of man but who remain deprived of true language, artificial or human attention can only manifest itself as an embrv'onic state, by flashes and sudden illumination without duration. This helps us to understand the origin of atten- tion. . . . In a previous memoir [Boutan, 1913] I have reported observations made upon my anthropoid Pepee. ... In brief, the animal systematically saves its attention. It seems afraid to fix it, and in fact when its attention is strongly awakened, it soon suffers extreme fatigue. I ask myself if. in an animal of superior organization like Pepee, we do not find at once the two different manifestations of attention : animal attention which manifests it- self normally in the habitual acts of life; artifi- cial or human attention which manifests itself ex- ceptionally, in a fragmentary embryonic form, in certain particular cases in the primates. In the experiments with boxes Pepee, stimulated by de- sire for food, manifested the sustained attention of the animal excited by the sight of the food in the box. In certain experiments we have some- thing different, however. In experiment 22, for example, the memory of the noi^e caused by the spring seemed to destroy the commencement of an artificial attention. [Footnote:] When for any reason I have multi- plied the number of experiments, it has been said to me on my return to the house, "Pepee must have worked more than usual today. She wa? fatigued and after her lunch went to sleep.'' If one reflects that the work Pepee did consisted in opening a box in order to obtain food, one can- not attribute the fatigue to muscular effort. I must add that this fatigue was chiefly e\'ident in the experiments with the more complicated appa- ratus. (Pp. 60-64.) The general conclusions of Boutan from his prolonged study of the gibbon we thus freely translate. RECEPTIVITY AND ADAPTIVITY IN GIBBON In these experiments the gibbon Pepee independently acquired certain new ideas. She retained for months the memory of these ideas and the movements appropri- ate to her successful (adaptive) acts. She lacked prevision of the proper movement, but she foresaw her objective. In her con- sciousness the idea of movement is inde- pendent of the movement itself. Under or- dinary circumstances the animal manifests natural or spontaneous attention, whereas in exceptional cases the beginnings of arti- ficial or voluntary attention may be ob- served. These flashes of the characteristi- cally human sort of attention caused the gibbon extreme effort and rapidly induced fatigue. In concluding this exposition of the Bou- tan investigations we may suggest certain criticisms which would inevitably occur to any careful reader of the original reports. The investigator's experimental tech- nique is far from perfect, indicating the novelty of the undertaking for him, as for Pepee. The problems presented are few and lacking in sufficient variety and grada- tion of difficulty to yield adequate factual basis for the author's conclusions. His ob- servations also are few, and even where the behavior of the subject is described in rea- sonable detail, it leaves with the reader the conviction that cases should be multiplied. Boutan may have made some shrewd guesses — we are inclined to believe that he did; he may have evaluated and inter- preted his observations conservatively, sanely, safely. But assuredly radical ob- jectivists will not grant this; and certainly he has taken entirely unnecessary risks of error by limiting his observations to so few types of problematic situation. Our appre- ciation of the work is so lively that we would not willingly end this paragraph with destructive criticism. Happily there is abundant evidence throughout the reports that the author took his research seriously and gave much thought to his problems, experiments, and the interpretation of re- sults. After the previous pages had been writ- 99 ten there appeared a contribution to the comparative study of intelligence in cats, dogs, monkeys, and anthropoid apes by Drescher and Trendelenburg, which reports certain observations on a gibbon whose sex and species are undetermined. It is particu- larly worthy of remark that the authors do not include the gibbon among anthropoid apes, and, further, that their observations support the conclusion that this creature behaviorally more closely resembles the monkeys than the great apes. A few experimental tests made with the gibbon by these authors are thus briefly describable. Given a rake with which food might be secured, the gibbon behaved essentially as did monkeys which were similarly tested. 'Tt drew in the fruit when it lay in front of the rake, but made no movements to place the rake behind the fruit when it lay further away." (Drescher and Trendelen- burg, 1927, p. 618.) When confronted with a box with re- movable cover in which it had seen food placed, the gibbon immediately opened it correctly. If placed in different positions, the cover was operated from the correct side if the animal had observed the closing of the box (p. 631). When later the cover of the box was fastened with a bolt, the animal succeeded within three days and after a number of trials in solving the problem. Of its attitude in the experiment the authors remark: It was shy and easily distracted, but extraordinarily alert and interested in the placement of the food. Also it was more skilful manually than the chimpanzees and orang-outans which were observed. Somewhat detailed description of the gibbon's method of operating the bolt indicates very distinctly inferiority of pro- cedure to that of the great apes (p. 635). We have now completed the presentation of what prolonged and diligent searching of the world's literature has revealed con- cerning the natural history and behavior of the gibbon. It is little in comparison with the needs of psychobiologists, and it is surprisingly meager and unreliable even 100 A STUDY OF ANTHROPOID LIFE from the non-professional point of view. To mention studies which should be made on the gibbon would be equivalent to offer- ing a program of anthropoid research, so little do we know and so uncertainly. We shall close this section of our book with the optimistic prophecy that before another quarter century has elapsed the life, and especially the psychobiology, of gibbons will be more thoroughly and more accu- rately known than are those of our domes- ticated animals at present. The publications, listed in our general bibliography, from which we have derived especially useful information concerning the life of Hylobates and Symphalangus are: Anderson (1878), Audebert (1800), Bennett (1832, 1834), Blanford (1889- 91), Blyth (1844, 1875), Boutan (1913, 1 9 14), Brehm (1922), Broderip (1849), Candler (1903), JJebeaupuis (1924), Drescher and Trendelenburg (1927), El- hot (1913), Figuier (1870), Forbes (1894), E. Geoffroy-Saint-Hilaire and F. Cuvier (1824), Harlan (1825, 1834), Heck (1922), Hornaday (1885, 1904), Hors- field (1824), Huxley (1863), Iperen and Schouman (1784), Keith (1895, 1896), Le Comte (1697), Lewis (1834), Lydekker (1894, 1897, 1904), Mahoudeau (1913, 1913a), Martin (1841), Mitchell, P. Chalmers (1912), Ogilvie (1923), Po- cock (1905), Rennie (1838), Robinson (1925), Sanyal (1907), Schlegel (1876), Schmidt (1886), Shaw (1800), Shelford (1916), Sonntag (1924), Spaeth (unpub- lished manuscript), Tickell (1865), de Visme (1769), Welch (1911), White (1799), Yerkes (1925), Yvan (1853). PART III ORANG-OUTAN ORANG-OUTAN CHAPTER NINE STRUCTURAL APPEARANCE, SPECIES, DISTRIBUTION, AND HABITAT OF ORANG-OUTAN THE order of arrangement of anthro- poid types in this work was sug- gested by geographical relations and degree of arborealness. The gibbon and orang-outan are Asiatic; the chimpanzee and gorilla, African. Furthermore, the or- der of decreasing structural adaptation for arboreal life and of addiction to it is as above: gibbon, orang-outan, chimpanzee, gorilla. Following this natural order we of- fer as Part III an account of the behavior of the orang-outan. Despite early and persistent confusion of this creature with other anthropoid types, unjustified multiplication of species, and many erroneous or inaccurate structural and behavioral descriptions, the scientific literature on this ape is much more exten- sive, varied, detailed, and reliable, and con- sequently more nearly complete and ade- quate than that on the gibbon. But it would be misleading to characterize it as satisfactory, since it is only in comparison with the obviously inadequate data on the gibbon that it appears ample and excellent. Although we tnow much concerning the natural history and even the psychobiology of the orang-outan, it still must be ad- mitted that, as in the case of the gibbon, we are at the very beginning of our quest for facts and understanding. HISTORICAL SUMMARY Hastily reviewing the content of our his- torical chapters, we note that knowledge of the orang-outan by the ancients is not well attested. Pliny may have included it among the Syrictae; and according to the infer- ences of Camper and Tyson from his ana- tomical writings, Galen probably dissected it. But since Tyson confused the orang- outan with the chimpanzee, we may not place full confidence in his belief that Galen was familiar with the great Asiatic ape. The vague descriptions by Marco Polo may refer to either gibbon or orang-outan, and we suspect that it is rather the former than the latter. The first to use the name "orang-outang," as far as we have discov- ered, was Tulp (1641), who, however, mis- applies it to the chimpanzee, designated by him as Satyrus Indicus, from Angola. The first unmistakable appearance of the orang-outan in scientific literature dates from 1658, when Bontius published his valuable description. From that time to the middle of the eighteenth century the his- tory of the animal may be traced through such authors as Le Comte (1697), Tyson (1699), Schouten (1707), Leguat (1708), Beeckman (1718), Careri (1727), and Hoppius (1760). Under the name Pyg- maeus, the latter author refers unmistak- ably to the orang-outan, since he describes its coat as ferruginous, not unlike a well- baked brick. Buffon in his early descriptions mistook the immature and the mature animals for different species, and designated the for- mer or smaller form as Jocko and the larger form as orang-outang. Both forms he believed to occur in Africa and in the Asiatic region. In the 1789 supplement to his natural history, having in the mean- time seen a living orang-outan, he partially corrected his error by calling it Jocko and the African chimpanzee Pongo, but he con- tinued to regard both as species of orang- outan. 104 A STUDY OF ANTHROPOID LIFE For another fifty years confusion per- sisted, as witness the works of Linnaeus (1766), Monboddo (1773), Vosmaer (1778), Camper (1779), Wurmb (1781). The contributions of several of these ob- servers greatly advanced knowledge, espe- cially of the structure of the ape, but it was not until the early years of the nineteenth century that confusion of the orang-outan with the great apes of Africa disappeared. Audebert (1800) pointedly criticized the prevailing usage of terms and resulting confusion of types, and Abel (1818, 1825) definitely stated that the apes of Africa should not be mistaken for or confused with those of the East Indies. Gradually since his time knowledge has accumulated until there is now no vestige of confusion. A useful historical review may be found in Kerbert (1914). STRUCTURAL CHARACTERS As much as a century ago competent ob- servers referred to the orang-outan as a rare animal, and its numbers have prob- ably since then decreased. But on this sub- ject we have no reliable information, for census of the anthropoid inhabitants of Borneo and Sumatra has not been taken. The following attempt at general de- scription of the structural traits which dominate the configuration of this great ape, and enable one to recognize it, is full of relative terms and applies only to the imaginary, average, mature male. The ani- mal is heavy in build, with short thick neck, long arms, short bowed legs, well- developed chest and prominent abdomen. Often it is characterized as unsightly or ugly in appearance, and quite as frequently as sluggish in its activity. The adult orang- outan differs remarkably from the gibbon. The former is large and heavy, with abdo- men more conspicuous than chest, clumsy and relatively inactive; whereas the latter is small and light, with large chest and small abdomen, graceful, agile, and ex- traordinarily active. Although there is no lack of physical measurements, they are usually incompar- able and peculiarly difficult to evaluate be- cause of variety in conditions of observa- tion and methods employed. Some data are drawn from living specimens, but more often they are estimates than accurate measurements. Some are based on freshly killed animals, others on preserved speci- mens, and yet others on skins, stretched in varying degrees. Having attempted from this heterogeneous collection of data to ob- tain averages, we finally concluded that it is impossible and that typical selected measurements are more safely indicative of size. A giant specimen described originally by Clarke Abel (1825, p. 493) as 7 feet 6^ inches in height, is said by Blyth (1841a, p. 837), who subsequently examined it, to have been an immature individual of or- dinary size. Referring to mature indi- viduals, and deriving his data from nine males and seven females, Wallace (1869, I, 96-97) presents for the males: height erect, 49 to 50 inches; width of face, 10 to 13^ inches; arm span, 86 to 92 inches. This author further observes that his measurements agree closely w^ith those of other observers. Hornaday (1904, p. 10) states that his largest specimen measured 54 inches in height, 42 inches around the chest, and 96 inches in arm span or reach. The width of face he gives as 13 inches; the maximal length of hand as 11^ inches; its width. 3^4 inches; and the maximal length of foot, 13^ inches. His paragraph ends with the following somewhat surprising assertion: "The weight of a large, full-grown male Orang is about 250 pounds." As a matter of fact, data on weight are few and very unsatisfactory. Although the Hornaday statement may well be correct, it probably applies to an exceptionally large male, for a careful comparison of all of the data which we have been able to find seems to justify the statement that the weight of the mature orang commonh- varies, as Hornadav himself states else- where (1879, p. 447). between 120 and 160 pounds. The females usually are con- SPECIES AND DISTRIBUTION OF ORANG-OUTAN 105 siderably smaller than the males. Seldom are comparable measurements on living specimens given for the two sexes. For additional data on size see Tem- minck (1835-41), Schlegel and Mliller (1839-44, p. II), Brooke (1841, p. 57), Blyth (1853), St. John (1862, pp. 21-22), Fick (1895, 1895a), Keith (1896, p. 321), Priemel (1908, p. 79), Knauer (19 15, pp. 23-24). Because of changes in the shape and proportions of the body and in the shape of the skull, special skin growths and growth of the hair, the appearance of the orang- outan alters amazingly during its life his- tory. Not uncommonly systematists have Fig. 42. Changes in the facial outline and cranium of the orang-outan from infancy to maturity. This drawing by Owen is reproduced from Martin, 1841, p. 390. mistaken young and adult specimens for different species. During infancy and childhood the animal much more closely resembles man in appearance than at any later period in its life history. With growth the facial angle diminishes greatly, the skull becomes more pointed and acquires ridges or crests, the jaws and teeth become conspicuous, and the occasional appearance of cheek pads and a fold of skin over the throat transform the creature into some- thing unrecognizable as a development from the infantile condition. Failure to in- dicate definitely the stage of an individual's development by exact description of struc- tural conditions or statement of chronologi- cal or physiological age, is a perennial source of error, misunderstanding, and il- legitimate structural and behavioral com- parisons. A distinguishing mark of the animal is its coat of hair. By this alone it ordinarily may readily be distinguished from every other type of anthropoid ape. Except for the face, ears, palms, and soles, the body regularly is covered with reddish brown hair of varying length and abundance. In important respects it varies extremely with individuality and age. Schlegel and Miiller (1839-44, p. 10) observed that whereas in most specimens the color is a handsome red-brown, in some it is