MAMMALS AND MANKIND 



769 



Chap. 37 



ing of whales is the expiration of warm air from the lungs condensed by the 

 coolness of the surface water. 



Primates. Lemurs, monkeys, apes and man are all primates (Figs. 37.19, 

 37.20, 37.21, 37.22, 37.23). Primates take hold of things with their hands. 

 Their coordination of eyes and hands is one of their basic characteristics. The 

 remote ancestors of man lived in trees, constantly climbing, gripping a branch, 

 aiming at another branch and leaping to it, repeatedly catching a swinging 

 vine and balancing upon it. They required an effectual combination of eye, 

 hand, and brain work. Those tree dwellers were trapeze performers with 

 mobile forelimbs that reached and stable hind ones that pushed. As the ages 

 passed some, probably the smaller ones, tree shrews, lemurs, monkeys, and 

 others remained in the trees; larger ones took to the ground. Among the 

 latter were the ancestors of the manlike apes, and after untold generations 

 of them there were prehistoric human beings. 



Fig. 37.20. Left, lemur (Galago) and right, Tarsius — two members of the 

 Order Primates which includes mankind. All primates have four generalized limbs 

 each with five digits bearing nails. Lemurs are the most primitive of primates, 

 small nocturnal animals that live in trees especially in Madagascar; some are as 

 small as a mouse, others as large as a cat. Their right to belong in the primates is 

 in the shortening of the jaws and greater size of the brain. Tarsius shows signs 

 of relation to the higher primates, most of them associated with its arboreal life. 

 Like those of many nocturnal animals its eyes are very large. They are turned 

 completely forward as in the human face and close to the nose. Like other tree 

 dwellers the capacity of the eyes has increased, that of the nose decreased. The 

 upper lip is uncut and its shape suggests that of monkeys and man. {Left, courtesy, 

 American Museum of Natural History, New York. Right, after Vogt and Specht. 

 Courtesy, Rand: The Chordates. Philadelphia, The Biakiston Co., 1950.) 



