INTELLIGENCE, POWER, 



hippopotamus, relatively small brains, namely, 700 grams 

 for the giraffe and 723 grams for the hippopotamus. Since 

 the hippopotamus has no enemy there would be but little 

 provision in the brain for sight and hearing, but the hippo- 

 potamus, in its swamp and water environment, would find 

 the sense of smell important. Therefore, as we expected, 

 the olfactory region of the brain was more prominent in the 

 hippopotamus than the ophthalmic or acoustic region. 

 Of such little biologic value is sight to this placid pachy- 

 derm that the eyes of the hippopotamus weighed only 

 42.70 grams, which is less than the weight of the eyes in a 

 94-pound impala. The eyes of the giraffe weighed 127 grams. 



We are fortunate in having for comparison with our 

 i,2OO-pound young female hippopotamus a warm-blooded 

 animal from the cold arctic sea. 



In the arctic the walrus has the same relative status as 

 the hippopotamus in the tropics. Like the hippopotamus 

 the walrus spends much of its time in the water. It does not 

 need to support its weight against gravity and therefore 

 needs less energy. Like the hippopotamus the walrus has no 

 formidable enemies. Like the hippopotamus the walrus has 

 stationary food and engages neither in the hunt nor in the 

 chase 



These two animals, with so many factors in common, 

 have one important factor in variance, namely, the habitat 

 temperature. The hippopotamus in the tropics requires 

 little oxidation for maintaining its body temperature at 

 98.6. The walrus, in the cold of the arctic, requires a large 



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