58 evolution: the ages and tomorrow 



How did all this come about? In the fossil record which 

 will be reviewed shortly we get some definite help in an- 

 swering the question, but to a certain extent we have to 

 guess what it was that caused in man alone of all primates 

 the original full bipedality and upright posture. Man's pres- 

 ent condition, his hairlessness, his clothing, his carnivorous- 

 ness, and his linearity, as anthropologists see it, strongly 

 indicate that his proto-human ancestors were adapted to 

 tropical surroundings and were caught off base by the 

 Pleistocene ice ages. The fossil record would seem to sup- 

 port this assumption. He survived because he had freed his 

 hands and his ego expanded through their manipulations, 

 aided by truly stereoscopic eyes and the deep curiosity- 

 drive of his ape heritage. 



Apparently, man was not forced out of his original home 

 in the trees by any recession of the forests due to the uplift- 

 ing of the Himalaya Mountains, as was once supposed. 

 Hooton's sly remark that any ape could swing himself 

 through the trees faster than a forest could recede has not 

 helped this cataclysmic theory. It would seem that man, 

 like the present gorilla and to some extent the chimpanzee, 

 simply became too heavy for easy monkeyshines on the 

 trapeze. Also, he possibly came down for dietary reasons, 

 as is also the case of the gorilla and the chimpanzee. 



The belief that man was originally a tree-dwelling ape is 

 forced upon anthropologists by his general body structure, 

 the shape of the human foot and hand, and by his social and 

 sexual inclinations, as well as his instincts, not the least of 

 which is the hand grasping reflex of the newborn baby. 

 The chief difference in man's descent from the trees and 

 that of other apes is that he refused to revert to an awk- 

 ward four-footed gait, and thus he freed his hands. Happily, 

 in the fossils of bones from South Africa we now have a 

 clear record of a man-like ape, along the line of man or a 

 side branch, which walked erect using the hands as man 

 now does. This fossil also shows how changes in the hip 



