8 NO STRUGGLE NO SELECTION 



tenance. In the case of many species it is easy to 

 account for the fact that they do not increase in 

 undue numbers, as for instance in the case of the 

 antelope and other herbivorous animals that are non- 

 prolific, and as a rule produce but one offspring at a 

 time. These creatures are born for two ends: the 

 first being to enjoy their own existence and propagate 

 their kind ; the second being to afford sustenance to 

 the carnivorous animals to whom they supply the 

 necessary amount of food. 



It is obvious that if such herbivorous animals are 

 to fulfil those ends, the creatures that prey upon 

 them must not be too numerous, otherwise the prey 

 would in process of time be exterminated ; while, on 

 the other hand, if the carnivorous devourers were too 

 few, the herbivora would increase to an undue extent. 

 It is evident, therefore, that Nature must have a 

 definite plan by which she maintains from generation 

 to generation a due proportion between the numbers of 

 the carnivora and the creatures which form their 

 natural food. Of the manner in which Nature keeps 

 true the balance of life between them, I shall speak 

 at the close of this chapter. 



If we ask what are the causes of destruction which 

 eliminate the excess of Nature's reproduction, and 

 contemplate her various higher or vertebrate types, it 

 is obvious at a glance that the carnivora hold the key 

 of the position ; for they are Nature's agents for 

 keeping within due bounds the numbers of all the 

 herbivorous forms of life, even such forms as the 



