242 EVOLUTION AND GENETICS 



1. Resemblance to surroundings, involving both color and 



form, for the concealment of both hunter and hunted. 

 This has been called protective and aggressive colora- 

 tion. 



2. Alluring colors to attract prey. 



3. Warning colors indicating noxious qualities. 



4. Signal and recognition marks. 



5. Confusing colors. 



6. Sexual colors. 



7. Mimicry of other organisms. 



Protective and Aggressive Colors. The efficacy of these adapta- 

 tions has been questioned, and we may well imagine that ani- 

 mals often perish in spite of them. However we cannot doubt 

 that the white winter coat of a prairie hare is more of a protection 

 when the ground is covered with snow than its brown summer 

 coat would be. Nor can we doubt that the similar resemblance 

 of the arctic fox to its environment enables it to approach its 

 prey with greater certainty of success than if it were red. The 

 writer and a friend once took a picture of a whip-poor-will resting 

 on dead leaves, and could never decide which object in the picture 

 represented the bird! As in other cases, the effectiveness of these 

 adaptations, even if limited, is sufficient to account for their 

 continuation, although not necessarily responsible for their 

 origin. 



Alluring Colors. Such colors involve a degree of mimicrj^, in 

 that the animal must resemble something attractive to its prey. 

 In approaching the supposedly dcsiral^le object, the prey comes 

 within the reach of the aggressor. 



Warning Colors. Many poisonous or unpalatable animals are 

 brightly colored, and are usually avoided by other animals. 

 Among these are the Gila Monster of southwestern deserts, the 

 red-banded coral snake, and the brightly colored or conspicuously 

 marked insects such as the wasps and bees and many unpalatable 

 species. Marshall records definite evidence that a few trials of 

 such insects result in their refusal by birds and monkeys. There is, 

 of course, nothing intrinsically repellent about their colors, but 

 they serve to impress upon the memory of a bird or animal, that 

 the insect which wears them is not good food, and to bring about 

 ready recognition upon later encounters. 



