AND PERSONALITY 



lift it from the ground, or capture it in mid-air. The vulture, 

 constantly soaring, scans the ground for food, which, being 

 dead, cannot run away. Since it is soft no unusual energy 

 is required to devour it. Theoretically, therefore, one would 

 expect to find that the eagle possesses larger celiac ganglia 

 and plexuses than the vulture. 



The energy requirements of the vulture are on the order 

 of the long-pursuit animals, such as the wolf, whereas the 

 energy requirements of the eagle are on the order of the cat 

 family that rush their prey. 



If it is through the sense of sight that the vulture and the 

 eagle detect their food, then the eye and the optic lobes of 

 the brain would be not only highly developed but also 

 comparable in size, and the eye itself would show telescopic 

 properties and a high ratio to the body weight. On the 

 other hand, should it be through the sense of smell that the 

 vulture detects food, then the olfactory lobes of the brain 

 would be prominent, as in the case of the dog family. 



On the same day that we dissected eagles we dissected 

 vultures. The brains of the eagles were all relatively larger 

 than the brains of the vultures. The olfactory lobe of neither 

 the eagles nor the vultures indicated that they detect their 

 food through the sense of smell. On the contrary, the optic 

 lobes in both the vultures and the eagles were highly devel- 

 oped. In the eagles the two eyes weighed more than twice 

 as much as the brain. In the vultures the eyes weighed 

 slightly less than the brain. 



In the eagles the adrenal glands were ij times as large 

 as the thyroid gland, following the pattern of the cat 

 family; in the vultures the thyroid glands were nearly equal 

 to the adrenal glands in size, as in the dog family. These 

 facts interpret definitely the contrasting behavior charac- 

 teristics of these two great birds. 



Let us now compare the energy-controlling organs of 

 birds that are both larger and smaller than the vulture and 

 the eagle and that are neither scavengers nor birds of prey. 



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