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Show 178 MR. R. I. POCOCK OX A HAINAX GIBBOX. [May 16, This conclusion respecting the descent of the Gibbons may be inferred from their habits alone, quite apart from structure. If the Anthropoid Apes be ranged in series according to proficiency in bipedal locomotion, the order will be (1) Gibbons, ( 2) Gorillas, (3) Chimpanzees, (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 up light, as Man and Gibbons do. Their usual walk is quadrupedal. Chimpanzees, too, are essentially quadrupedal; and under ordinary conditions, and when in perfect health, almost always get over the ground on " all fours," like a Baboon or Rhesus. In this respect, indeed, they more resemble the Cercopithecoid 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 quadrupedal 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 described as a clumsy quadrupedal shuffle. I never saw one stand unsupported by the arms. Weakness 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 Avhole organisation suggests unfitness for terrestrial locomotion. Thus, if the Apes be classified according to their quadrupedal activity on the ground, they will stand:-(1) Chimpanzees, (2) Gorillas, (3) Orangs, (4) Gibbons. It is interesting to compare this series with one based upon dexterity in climbing and addiction to arboreal life. It is : (1) 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 summarised as follows :- The Gibbons are the most expert climbers and bipedal walkers, the least expert quadrupedal walkers. The Orangs rank second 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 * These and the following statements and reflections are based upon my own observations of the Anthropoid Apes that have come under my notice in the Society's Gardens. |
