MAN AND NATURE 9 



interfere with any animals or the habitats of any animals without inter- 

 fering with many others. The second is that all animals are of some 

 economic importance. The third, that few animals can be said to be 

 either wholly beneficial or wholly noxious, excepting those reared or 

 preserved for their direct utility, and those directly and perniciously 

 attacking the necessities of man's existence. 



Considering the first, we note that civilized man's operations interfere 

 with animals and animal habitats. His first work is to destroy all large, 

 dangerous animals. He clears and cultivates the land, bringing death 

 and destruction to many more, and gradually substitutes domestic ani- 

 mals for wild game (50). Vegetarians often argue for the exclusive use 

 of vegetable food on the ground that animals should not be killed, but 

 to secure more plants for this purpose they of necessity would clear more 

 land to grow more corn and thus destroy myriads of animals by methods 

 more cruel than those of the butcher and huntsman. Our relations to 

 animals are not simple, but very complex and our conduct often inconsist- 

 ent. We cease wearing aigrettes because the collecting of them often 

 leaves young birds to die, and kill every mouse and mole that happens 

 to come our way, though their young must die as do those of the birds. 

 Some of us wear leather shoes while arguing for a vegetarian diet because 

 animals should not be cruelly slaughtered. 



Turning to the second and third ideas stated above, we note that 

 few animals which feed upon a variety of foods, both plant and animal, 

 can be said to be of any great usefulness, except when the plants eaten 

 are useless to man. In other words, the good done the farmer by an 

 animal which eats many insects, including noxious ones, may be offset 

 by a destruction of grain. Birds eat a variety of food. Those feeding 

 upon useful plants are not rated as of great economic importance. The 

 bobolink, for example, eats grain and weed seeds in the spring when 

 insects are scarce; soft-bodied insects in June and July when seeds are 

 not available. In August the insects mature and are hard shelled. The 

 birds now reject them for the grain seeds. This bird, furthermore, eats 

 that which is available and most easily secured during the different 

 seasons. This is also true of many, probably the vast majority of 

 animals. The food of fishes is to a considerable extent determined by 

 the kind of food available where they are living (6). Ruthven (7) has 

 found this true of garter-snakes; the same is true of men. 



Many animals, birds (8), mammals, reptiles (9), toads (10), and 

 insects destroy quantities of noxious insects, but along with them many 

 insects that are enemies and parasites of the noxious ones are also 



