The Making of Species 



" we consider the habits and life-histories of those 

 animals which are more or less gregarious, com- 

 prising a large proportion of the herbivora, some 

 carnivora, and a considerable number of all orders 

 of birds, we shall see that a means of ready 

 recognition of its own kind, at a distance or 

 during rapid motion, in the dusk of twilight 

 or in partial cover, must be of the greatest 

 advantage and often lead to the preservation of 

 life. Animals of this kind will not usually 

 receive a stranger in their midst. While they 

 keep together they are generally safe from 

 attack, but a solitary straggler becomes an easy 

 prey to the enemy ; it is therefore of the highest 

 importance that, in such a case, the wanderer 

 should have every facility for discovering its 

 companions with certainty at any distance within 

 the range of vision. 



" Some means of easy recognition must be of 

 vital importance to the young and inexperienced 

 of each flock, and it also enables the sexes to 

 recognise their kind and thus avoid the evils 

 of infertile crosses ; and I am inclined to believe 

 that its necessity has had a more widespread 

 influence in determining the diversities of animal 

 colouration than any other cause whatever. To 

 it may probably be imputed the singular fact that 

 whereas bilateral symmetry of colouration is very 

 frequently lost among domesticated animals, it 

 almost universally prevails in a state of nature ; 



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