Adaptive Mimicry, 55 



stances, both to escape being eaten themselves, and to gain 

 opportunities of eating other creatures. Accordingly we find that 

 every creature which in any way needs concealment is furnished 

 with the means of concealment, and of these the commonest and 

 most obvious are modifications of colour. In most countries a 

 white colour would be certain danger; among arctic snows on the 

 contrary a white colour is a protection, and accordingly the polai* 

 bear is the only bear that is white ; the polar hare and fox and 

 ermine turn white in winter ; the snow bunting is white, and the 

 ptarmigan, which in summer is mottled and speckled, to the exact 

 tint of lichen-coloured stones, becomes in winter as white as the 

 snows among which it lives. But on the other hand, the birds, 

 the snakes, the lizards, all the small mammals that live in 

 the sandy desert, even the camel itself are all sand-coloured ; 

 in the boundless evergreen tropic forests the prevalent colour 

 of the birds is green, and the reptiles too are green, except 

 those to whom the colour would be useless because they 

 live in holes; while the tiger is striped like the black . shadows 

 of the bamboos, and the panthers are ocellated like the sun- 

 spotted leaf-shadows, except the ashy puma which clings so 

 close to the trees that it is hardly distinguishable from the bark. 

 If we turn to fishes we find that they are mostly of the colour of 

 the waters in which they swim, or the sand and gravel on which 

 they rest; and just as the butterflies which live among flowers may 

 safely wear gorgeous colours, so those fish that live among the 

 many-tinted corals and seaweeds of tropic seas, may flame about 

 with safety in purple and gold. In this latter fact we see that 

 when colour will do an animal or insect no harm, the causes which 

 lead to the development of colour act unchecked ; if an animal is 

 safe in an unpleasant odour, or in a hard shell, or in impenetrable 

 scales, or by the possession of a sting, or by hard spines and 

 excrescences, or by curious tentacles and threatening attitudes, 

 and if, in addition to this, it gets its prey by night, then it may 

 wear with perfect safety all the colours of the rainbow — as for 

 instance our little Coccinellae, which birds never eat, partly because 

 of their hard wing-cases, partly their disagreeable smell; but if it 

 is devoid of all such means of protection, it must escape either by 

 being perfectly inconspicuous, or by so closely resembling some 

 other objectionable animal, that it may deceive by means of their 

 resemblance, the birds or beasts which would otherwise be its 

 enemies. 



There is another very curious aspect of this subject, and that is, 

 that these adaptive mimicries are almost universally found among 

 the females of insects and birds. For instance, the very numerous 

 Heliconidae of Brazil, being splendidly beautiful with their spots 



