Yet, the stony silence of an endocast has not daunted a number of 

 workers from drawing inferences from the comparative and developmental 

 fields. At the crudest level, such studies have related the size of the brain 

 to the size of the body, of the orbit or eyeball, of the foramen magnum, 

 of the spinal cord, or of various other bodily features. 



Brain size and body size 



A study of the size of the brain in relation to body size has been 

 employed chiefly in comparisons between species, in an effort to show how 

 preeminent the brain has become in man. It was Cuvier who first introduced 

 the concept of relative brain weight, that is, the weight of the brain ex- 

 pressed as a fraction of the weight of the body (Krompecher and Lipak 

 1966). Cobb's picture of a small human female standing alongside a rhinoc- 

 eros shows graphically the difference in relative sizes of brains. The woman 

 may have a brain weight of 1200 gm. in a body weighing, say, 45 kg., 

 whereas the rhinoceros has a brain that may weigh 600 gm. in a body of 

 about 2000kg. (Cobb 1965). The brain/body ratio in the rhinoceros is 

 1:3300 in such a case; that of the woman is 1:38. Even more revealing is 

 a glance at a Brontosaurus, one of the great dinosaurian ruling reptiles, 

 perhaps 65 feet long, that lived in the Jurassic period: its brain constituted 

 a mere 1/100, oooth of its 35-ton bulk. A whale has a brain/body weight 

 ratio of 1 : 10,000; an elephant's is 1 :6oo; a gorilla's is 1 :20o; and a man's is 

 about 1:45 (Table 16). 



But it is sobering to see that while man's exalted brain constitutes just 

 over 2 per cent of his body weight, this percentage is surpassed by that of 

 the lowly house mouse (2.5 per cent, or 1:40), the porpoise, with a 1:38 

 ratio, the marmoset, with a 1:19 ratio, and the delightful little squirrel 

 monkey (Saimiri) of tropical America whose brain occupies Math, or 8.5 

 per cent, of its body weight (Cobb 1965)! Because man, the sapient, did 

 not come out at the top, it is not surprising that man, the vainglorious and 

 the arrogant, has been searching ever since for a variety of strange indices 

 that would place him unequivocally and unassailably on the highest branch 

 of the tree of life. For example, when the length of the hypothalamus 

 is expressed as a fraction of that of the cerebrum, man has the lowest 

 fraction, and so comes out on top (Kunnner 1961); when the weight of 

 the spinal cord is expressed as a fraction of the brain weight, man has 

 the lowest fraction, and so conies out on top (Latimer 1950; Krom- 

 pecher and Lipak 1966); when the cranial capacity is related to the area of 



>J( .06 



