THE ANIMAL, MAN (ANTHROPOLOGY) 541 



hands, whereby their surroundings could be explored and objects 

 of interest brought up close to their sense-organs for examination. 

 This method was a vast improvement over the necessity of moving 

 the sense-organs, body and all, into the immediate neighborhood of 

 objects to be examined. 



As long as primates kept to the comparative security of aerial 

 apartments in trees, they necessarily could not attain large militant 

 size, for trees are no suitable place for heavy or bulky animals. So 

 the time inevitably came when certain of the primates, after a long 

 period of arboreal schooling, ventured more and more down upon 

 the ground until finally, in the case of man, the descent was made 

 permanent. The descent of ancestral man from an arboreal habitat, 

 however, resolves itself after all into an evolutionary ascent, or step 

 upward, for life is much more worth living on the ground than in trees. 

 There are more enemies to combat, and more necessity and oppor- 

 tunity for sharpening the wits. The table also is spread with more 

 available food, in particular a greater variety of vegetation, and, 

 in the animal world, creepers, crawlers, burrowers, runners, jumpers, 

 and swimmers, all good to eat, that are out of easy reach of tree- 

 dwellers. 



It w^as comparatively easy with increasing intelligence to make 

 the transition from sitting in trees to walking vertically on the ground, 

 and every human baby faithfully repeats the' ancestral story by 

 first sitting up on end before balancing on its hind legs in learning 

 to walk. 



Finally, it may again be repeated that none of the primates existing 

 today are to be regarded as directly ancestral to man, as is often 

 popularly supposed. 



The Consequences of an Upright Life 



As long as the forerunner of man went about on all fours, whatever 

 brain was present, being encased in a heavy bony skull, had to be 

 carried out in front of the body, at considerable mechanical dis- 

 advantage. In the case of the horse, for example, a large unwieldy 

 neck, made up of vertebrae and abundant muscles and tendons, is 

 necessary to guy the heavy head to the long, bladelike, bony, spinous 

 processes which stand up in a row behind. The check-rein of a 

 driving harness is man's contribution to the horse's age-old problem 

 of holding up its head. 



