178 MR. R. I. POCOCK ON A HAINAN GIBBON. [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 rai'ely, 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, 

 '/. e. progress with both feet off the ground at one time ; and 

 they probably never run from dangei", standing upright, 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 sliuiBe. 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 whole 

 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 seiies 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 w^alkers, 

 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 tlie 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. 



