76 BIOLOGY 



It has often been said that the struggle for existence 

 between fellows with the same needs is the keenest of 

 all, and numerous examples have been quoted in its 

 support. But this is not necessarily so, and is frequently 

 quite the opposite. We have seen numerous cases 

 where this is not so, and the animals seem to have 

 discovered various peaceful devices for preventing this 

 life and death struggle. 



Of the struggle for existence between foes little need 

 be said. Carnivores prey on herbivores, birds prey 

 on small mammals, and so on throughout the whole 

 realm of animal life. But birds may feed on insects 

 and worms, and fishes may live on small Crustacea, and 

 we must not be rash and strain the meaning of this 

 struggle for existence. 



Of the third form of struggle, the competition between 

 rival males for the possession of the female, there are 

 countless examples. But this is a competition in which 

 beauty and sweetness of song are often as important as 

 strength ; we have on the one side, for example, the 

 contest between rival songsters, on the other side the 

 fierce combats between stags. 



The struggle between organism and environment is, 

 in our opinion, the most important of all, for nature 

 seems absolutely careless of life. In a previous chapter 

 we have seen some of the devices by which animals keep 

 their foothold against storm and drought and cold. 

 One or two examples must suffice. Droughts are many 

 and frequent, the pools are dried up, most of the inhabi- 

 tants perish. But many of the simpler organisms, and 

 indeed a goodly number of higher forms, are warned in 



