The Mammals and Man 



twelve in man ; it has long arms, like the lower Old- World apes, 

 and large canine teeth. It is further the smallest of the group, 

 and in habits the most like the lower monkeys. 



The Gorilla and Chimpanzee are closely related. The Gorilla 

 is not only the largest ape of the four, but in shape and build the 

 most man-Hke, which is accounted for by the fact that it is less 

 strictly arboreal than the others, and confines itself largely to the 

 ground. Its skull is superficially much less human in appearance 

 than that of the Chimpanzee, due to the strongly developed crests, 

 which serve as attachments for the powerful muscles of the lower 

 jaw. The teeth of the Chimpanzee are more uniform in size, 

 and the skull smoother. There is a marked difference in tempera- 

 ment betvx^een the two species, the Gorilla being fierce and gloomy 

 and quite untamable, while the Chimpanzee is of a pleasant and 

 lively disposition, and can, as is well known, be trained to wear 

 clothes, eat with a fork and knife, etc. 



The Orang-Utan is found inhabiting forest ground in Borneo 

 and Sumatra, and living largely in trees, in which it builds nests 

 as temporary sleeping-places. It is a clumsy-looking animal, 

 supporting itself on the knuckles of its hands when travelling along 

 the ground, and moving but slowly. It has twelve pairs of ribs, 

 the same number as in man, and one fewer than in the Gorilla and 

 Chimpanzee. 



Practically all the important anatomical distinctions between 

 man and the anthropoids are reducible to two causes : the change 

 from the arboreal existence to a life on the ground and in the 

 open country, and the great development of the intelligence. 

 When the change in the mode of life occurred, it is obvious that an 

 erect carriage would possess an advantage over the stooping gait 

 of the ape, in which it is neither definitely a biped nor a quadruped. 

 The erect position necessitated a better-developed heel, stronger 

 calf and hip muscles, and a more parallel position and stronger 

 development of the great toe. It also brought about a shortening 

 of the fore-arms and a widening of the pelvis. Much has been 

 made of the difference in the foot, between the condition of a 

 grasping organ, with an opposable great toe, and that seen in man. 



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