CHAPTER 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. 1’oulton'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 undis- 
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 
