INTELLIGENCE, POWER, 



glands, in situ, of the gorilla collected by Dr. Henry Raven. 1 

 After careful measurements of the various dimensions were 

 made, the weight of the adrenal glands was estimated at 

 3 5 grams and the thyroid gland at 6 grams. The body weight 

 was estimated at between 375 and 400 pounds. 



In contrast to the adverse effect of captivity on the highly 

 energized animals, the low-powered animals such as alli- 

 gators, crocodiles, snakes, turtles, and fish seem indifferent 

 to captivity. In breeding and domestication, however, we 

 find variable effects upon the energy-controlling organs. 



Effect of Breeding and Domestication on the 

 Energy-controlling Organs of Animals 



The mechanism of the bull, the bullock, the ram, the 

 stallion, the buck, and other male members of the herds 

 and flocks of leaf- and grass-eating animals exhibits an 

 evolution of the characteristics of the male that in many 

 respects is the opposite to that of the female. Inasmuch as 

 the contribution of the female is greater, because of the 

 metabolic work of producing the young in her uterus and 

 of fabricating milk to carry the young over the helpless 

 period, her functions represent a very important adapta- 

 tion for the perpetuation of the species. The male is the 

 protector of the female as well as of all the other members 

 of the herd or flock. Therefore, natural selection, seizing 

 upon chance mutations, has endowed the male with a 

 larger brain, more powerful muscles, and better developed 

 and more powerful horns. In consequence, he protects the 

 female and the young against the carnivores. He fights off 

 the less fit males. He impregnates the females, securing 

 thereby the highest fitness in the offspring. Thus the male 

 is endowed with greater intelligence as well as greater 

 size, physical power, and bravery, a larger heart and a 

 larger blood volume than the female. 



1 GREGORY, WILLIAM KING, and H. C. RAVEN, "In Quest of Gorillas," Darwin 

 Press, New Bedford, Mass., 1937. 



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