288 DARWINISM 



beak towards the female, and chuckles with delight," while he 

 has never seen the more plain coloured thrush demonstrative 

 to the fem:ile. The linnet distends his rosy hreast, and 

 slightly exi)ands his l)rown wings and tail ; while the various 

 gay coloured Australian finches adopt such attitudes and 

 postures as, in every case, to show off their variously coloured 

 plumage to the best advantage. ^ 



A Theory of Aniiiml Coloration. 



Having rejected ]\Ir. Darwin's theory of female choice as 

 incompetent to account for the brilliant colours and markings 

 of the higher animals, the preponderance of these colours and 

 markings in the male sex, and their display during periods 

 of activity or excitement, I may be asked what explanation 

 I have to offer as a preferable substitute. In my Trojncal 

 Nature I have already indicated such a theory, which I will 

 now briefly explain, supporting it by some additional facts 

 and arguments, which appear to me to have great weight, and 

 for which I am mainly indebted to a most interesting and 

 suggestive posthumous work by Mr. Alfred Tylor.^ 



The fundamental or ground colours of animals are, as has 

 been shown in preceding chapters, very largely protective, 

 and it is not improbable that the primitive colours of all 

 animals were so. During the long course of animal develop- 

 ment other modes of protection than concealment by harmony 

 of colour arose, and thenceforth the normal development of 

 colour due to the complex chemical and structural changes 

 ever going on in the organism, had full play ; and the colours 

 thus produced were again and again modified by natural selection 

 for purposes of warning, recognition, mimicry, or special pro- 

 tection, as has been already fully explained in the preceding 

 chapters. 



Mr. Tylor has, however, called attention to an important 

 principle which underlies the various patterns or ornamental 

 markings of animals — namely, that diversified coloration 

 follows the chief lines of structure, and changes at points, such 

 as the joints, where function changes. He says, " If we 

 take highly decorated species — that is, animals marked by 



^ Descent of Man, pp. 401, 402. 

 ^ Coloration in Animals and I'lavts, Loudon, 1886. 



