Attributes of Successful Species 



to which they are unaccustomed will become 

 emaciated and perish. We see this in every hard 

 winter in England, when the redwing, which, 

 unlike other thrushes, cannot thrive on berries, is 

 the first to die. Most of the more successful 

 birds the crows and gulls, for example are 

 omnivorous that is to say, they are able to 

 digest all manner of food. 



Under mental capacity, we would include 

 cunning and sufficient intelligence to adapt one- 

 self to changed conditions. It is largely through 

 man's superior mental capacity that he has 

 become the dominant species. It is true that 

 he displays also courage and a good constitution, 

 being able to adapt himself to life under the most 

 diverse conditions ; but this is, of course, in part 

 due to his mental capacity, which enables him 

 to some extent to adapt his environment to 

 himself. 



The advantages of prolificacy are so apparent 

 that it is unnecessary to dilate upon them. 

 Nearly as important as excessive fertility is the 

 ability on the part of the parents to look after their 

 young ones. 



Every successful species possesses in a special 

 degree at least one of the above attributes. It 

 is interesting to take in turn the various species 

 which are most widely distributed and consider 

 to what extent they possess these several 

 qualities. 



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