60 EAGLE AND VULTURE 



WHETHER the soaring vulture locates carrion by the 

 sense of smell or the sense of sight is often a subject 

 of speculation. During the day one almost never sees a 

 vulture in Africa except when an animal is brought down; 

 then vultures drop from the sky in numbers. They come 

 apparently from long distances, with and against the wind, 

 as if they had been spread above the earth like a net. 



The collaboration of vultures is a fine example of coopera- 

 tion, since the carcass of one animal provides food for many. 

 Were there no cooperation, vultures would fare badly be- 

 cause of the rapid disintegration of the dead. By soaring in 

 the cool air, spaced apart, a network of vultures could form 

 an air patrol over most of the land in Africa. . 



The valiant eagle does not thus organize, for he kills no 

 animal larger than he can eat alone. The eagle is an indi- 

 vidualist. Speed with him is a prime necessity. He must 

 work fast and near the ground. Vultures and eagles repre- 

 sent two principles in nature, the cooperative and the 

 individualistic. 



By reason of cooperation the vulture spends little energy 

 for finding his food, since the telltale actions of those that 

 are descending serve as the signal to those still stationed 

 in the skies, and little energy is used in the actual process of 

 gorging. Thus the vulture is operated at a lower kilowatt cost 

 than the eagle, and vulture cooperation and economy of oper- 

 ation enable the land to support more vultures than eagles. 



Inasmuch as the eagle is adapted to soaring passively and 

 to flying vigorously and the vulture is adapted to soaring 

 passively and is not adapted to flying vigorously, we should 

 expect the vulture and the eagle to exhibit a distinct differ- 

 ence in their adrenal-thyroid relation and in the size of 

 their brains. 



The eagle must first overtake its prey, then seize and 



52 



