PRINCIPLES OF PROTECTIVE COLOURATION 211 



have been assumed to be those of enabling the animal to 

 disguise itself as some inanimate object— to pretend to be what 

 it is not ; secondly to hide itself from view altogether— to 

 disappear among its surroundings. By either of these two 

 faculties it is able either to escape from its enemies or to 

 approach within striking distance of its victim and thus to 

 survive in the struggle for existence. 



Of these four principles, only two are thoroughly accepted and 

 endorsed by Thayer : the whole trend of the evidence which he 

 has collected is towards the most drastic modification, if nothing 

 more, of the remaining two. Natural selection is the process 

 and concealment is the purpose of animal colouration. The 

 spheres both of sexual selection and of protective mimicry are, 

 in comparison, severely restricted. Animal colour schemes are 

 seldom if ever developed by the preference of the female for 

 showy colours and conspicuous forms, seldom if more often 

 used to preserve their possessor from notice by disguising him 

 as another object. Whatever may be the extent to which these 

 latter principles work, the main current of evolution, so Thayer 

 maintains, sets towards the survival or reproduction of the type 

 which most completely conceals itself. Though he is careful, 

 in his most important work, 1 to point out that his method is as 

 far as possible inductive, that he starts with no theories and 

 is only a collector of evidence, still the conclusion which he 

 wishes to be drawn from his data is obvious enough. It is, 

 in a word, that colouration for him means, in the animal king- 

 dom, concealing colouration. To accept his evidence is to 

 accept the principle that the colour scheme of the peacock like 

 that of the nightingale, of the zebra like that of the antelope, 

 of the butterfly like that of the caterpillar, has been developed 

 by the strict process of natural selection, as the best fitted to 

 conceal and to obliterate its possessor. 



Now, it will be evident that the strength of Thayer's case 

 lies in proving that animals are much better hidden in their 

 natural surroundings than the ordinary observer imagines, that 

 naturalists have been busy accounting for the conspicuous colours 



1 Concealing Coloration in the Animal Kingdom. An exposition of the laws 

 of disguise through colour and pattern. Being a summary of Abbott H. Thayer's 

 discoveries : by Gerald H. Thayer. With an introductory essay by A. H. Thayer. 

 Illustrated by A. H. Thayer, G. H. Thayer, Richard S. Merriman and others and 

 with photographs. Macmillan & Co., 3 is. 6d. net. 



