CHAPTEK VIII 



THE ORIGIN AND USES OF COLOUR IN ANIMALS 



The Darwinian theory threw new light on organic colour — The problem to 

 be solved — The constancy of animal colour indicates utility — Colour 

 and environment — Arctic animals white — Exceptions prove the rule — 

 Desert, forest, nocturnal, and oceanic animals — General theories of 

 animal colour — Variable protective colouring — Mr. Poulton's experi- 

 ments — Special or local colour adaptations — Imitation of particular 

 objects — How they have been produced — Special protective colouring 

 of butterflies — Protective resemblance among marine animals — Pro- 

 tection by terrifying enemies — Alluring coloration — The coloration 

 of birds' eggs — Colour as a means of recognition — Summary of the 

 preceding exposition — Influence of locality or of climate on colour — 

 Concluding remarks. 



Among the numerous applications of the Darwinian theory 

 in the interpretation of the complex phenomena presented by 

 the organic world, none have been more successful, or are more 

 interesting, than those which deal with the colours of animals 

 and plants. To the older school of naturalists colour was a 

 trivial character, eminently unstable and untrustworthy in the 

 determination of species ; and it appeared to have, in most cases, 

 no use or meaning to the objects which displayed it. The 

 bright and often gorgeous coloration of insect, bird, or flower, 

 was either looked upon as having been created for the enjoy- 

 ment of mankind, or as due to unknown and perhaps unclis- 

 coverable laws of nature. 



But the researches of Mr. Darwin totally changed our point 

 of view in this matter. He showed, clearly, that some of the 

 colours of animals are useful, some hurtful to them ; and he 

 believed that many of the most brilliant colours were developed 

 by sexual choice ; while his great general principle, that all 



