National Geographic : 1940 Aug
Man's Closest Counterparts Heavyweight of Monkeydom Is the "Old Man" Gorilla, by Far the Largest of the Four Great Apes BY WILLIAM M. MANN Director,National Zoological Park, Washington, D. C. ONE characteristic of the human being is that he is greatly interested in him self and other humans, so it is natural that he should also take a keen interest in the manlike apes. No one nowadays suggests that these mon keys are his ancestors; yet there is a great deal of resemblance in structural, physiologi cal, and even mental characteristics between the great apes and man. Apes have no tails; they often walk erect and make homes of a sort for themselves; they have the same number of fingers and toes and teeth as man, but not the same amount of brain. The smallest normal adult human skull known is an ancient one from Peru, whose skull cavity measures 910 cubic centimeters; the gorilla's brain measures approximately 600. The cranial capacity of a normal adult white man ranges between 1,300 and 1,900, with the average about 1,450. One psychologist who visited our Zoo and made a number of experiments concluded that our young gorilla, N'Gi, had the men tality of an average 18-month-old baby. Apes Snore and Have Appendicitis The great apes are subject to many of the same diseases as man. They have a vermi form appendix and sometimes they snore. Another resemblance to a human is that the young are exceedingly helpless. They live for months almost as external parasites on the mother. The period of gestation in the gorilla, chim panzee, and orangutan is nine months, the same as in man, and the baby at birth weighs from three to seven pounds. In the gibbon, somewhat lower in the scale, the period is only seven months. Heavyweight of the tribe is the gorilla, with longer arms than the chimpanzee, much more beetling brows, and a tremendous chest and paunch. Usually it travels on all fours on its knuckles. Though the gorilla seldom walks erect, it can do so better than the other apes, and it stands up when it beats its breast to express joy, rage, general exuberance, or even a warning to other members of the family (Color Plate I). One of our baby gorillas was fond of stand ing up and whirling around like a dervish until he finally lost his balance and fell over. The gorilla has smaller ears than the chim panzee and deeper, quieter eyes. Chimp Is Imp of the Ape Tribe The chimpanzee is more clownish in be havior, especially when young (Plates III, IV, and VIII). If one may compare animals to humans, the little boy chimpanzee is more like the little boy zoo visitor than anything else. He is the most precocious of the lot, full of playfulness, and loves to stamp mightily on the earth, or preferably on the floor of a cage where he can make more noise. A red-haired, red-headed "funny-face" is the long-armed orangutan (Plates II and IV). Babies are especially comical, but adults, with their massive cheek callosities and small beady eyes can be ferocious in looks as well as in action. They are the most arboreal of the three biggest apes and seldom come to the ground except to change from one tree to another when there are no intervening branches on which to travel. The gibbon, smallest of all, is the "baby doll" as a youngster, and when larger it be comes a superb gymnast, better than any other animal that I know. Most of its traveling is done by swinging by its arms from one branch to another, but on a level surface this acrobat is apt to run erect, balancing itself by outwaved arms (Plates V, VI, and VII). These four-the gorilla, chimpanzee, orang utan, and gibbon-are usually known as "the great apes," but the group varies enormously in size, from the gorilla to the small gibbon found on the Pagai Islands off the coast of Sumatra. One big baboon from West Africa would weigh as much as a whole family of these little creatures and yet they are called "great apes." The name undoubtedly was first applied to the gorilla, chimpanzee, and orangutan, all of which are large, but sys tematically the gibbons are included in this group. None of the manlike apes is found in the New World.