SIGHT IN SAVAGES 177 



eyed and swifter than he, are without intelligence, 

 and thus things are made equal. He can see the 

 rhea as far as the rhea can see him; and if he 

 possessed the eagle's far-seeing faculty it would 

 be of no advantage to him. The high-soaring eagle 

 requires to see very far, but the low-flying owl 

 is near-sighted. And so on through the whole ani- 

 mal world: each kind has sight sufficient to find 

 its food and escape from its enemies, and nothing 

 beyond. Animals that live close to the surface 

 have a very limited sight. Moreover, other facul- 

 ties may usurp the eye's place, or develop so 

 greatly as to make the eye of only secondary im- 

 portance as an organ of intelligence. The snake 

 offers a curious case. No other sense seems to 

 have developed in it, yet I take the snake to be 

 one of the nearest-sighted creatures in existence. 

 From long observation of them I am convinced 

 that small snakes of very sluggish habits do not 

 see distinctly farther than from one to three yards. 

 But the sluggish snake is the champion faster in 

 the animal world, and can afford to lie quiescent 

 until the wind of chance blows something eatable 

 in its way; hence it does not require to see an 

 object distinctly until almost within striking dis- 

 tance. Another remarkable case is that of the ar- 

 madillo. Of two species I can confidently say 

 that, if they are not blind, they are next door to 

 blindness; yet they are diurnal animals that go 

 abroad in the full glare of noon and wander far 

 in search of food. But their sense of smell is 



