42 THE STUDY OF ANIMAL LIFE CHAP. 



anthropomorphism which so easily besets us. We trans- 

 fer to the animal world our own experience of keen com- 

 petition with fellows of the same caste, and in so doing 

 are probably unjust. Thus Mr. Grant Allen wrote : 



" The baker does not fear the competition of the butcher in the 

 struggle for life ; it is the competition of the other bakers that 

 sometimes inexorably crushes him out of existence. ... In this 

 way the great enemies of the individual herbivores are not the 

 carnivores, but the other herbivores. ... It is not so much the 

 battle between the tiger and the antelope, between the wolf and 

 the bison, between the snake and the bird, that ultimately results 

 in natural selection or survival of the fittest, as the struggle between 

 tiger and tiger, between bison and bison, between snake and snake, 

 between antelope and antelope. . . . Homo homini lupus, says 

 the old proverb, and so, we maj 7 add, in a wider sense, lupus lupo 

 lupus, also. . . . The struggle is fierce between allied kinds, and 

 fiercest of all between individual members of the same species." 



These sentences give forcible expression to a widely 

 accepted conclusion that the struggle for existence is 

 keenest between fellows of the same species. But the 

 evidence is very unsatisfactory. In his paragraph sum- 

 marised as " struggle for life most severe between indi- 

 viduals and varieties of the same species ; often severe 

 between species of the same genus,' 3 Darwin gave five 

 illustrations : one species of swallow is said to have 

 ousted another in North America, the missel-thrush has 

 increased in Scotland at the expense of the song-thrush, 

 the brown rat displaces the black rat, the small Asiatic 

 cockroach drives its great congener before it, the hive- 

 bee imported to Australia is rapidly exterminating the 

 small, stingless native bee. But the cases of the rats, 

 cockroaches, and thrushes have not survived criticism ; 

 they do not justify the conclusion drawn. And on the 

 other hand, we know that reindeer, beavers, lemming, 

 buffaloes and many other animals migrate when the means 

 of subsistence are unequal to the demands of the popula- 

 tion, and there are other peaceful devices by which 

 animals have discovered a way out of a situation in which 

 a life-and-death struggle might seem inevitable. Very 

 instructive is the fact that beavers, when too numerous 



