DIFFERENTIATION OF INDIVIDUALS AND ADAPTATION 125 



162. The Preying Habit. The effects of this habit are 

 stamped upon the structure and activities of both the pursuer 

 and the pursued. It is in this relation that nature is indeed 

 "red in tooth and claw." While in general the same organs 

 and habits which are of value in the capture of prey are useful 

 in the defense of the possessor, it is possible to find a series 

 of adaptations of an offensive character and others more 

 specially of defensive value. The curved claws and sharp 

 teeth, the stealthy approach, the sudden spring, and the great 

 agility of the one are met by the timidity, the keen senses, 

 the fleetness of the other. We can see that these defensive 

 adaptations must keep pace with the offensive else the prey 

 would be exterminated, which would entail no less surely the 

 destruction of their enemies than if these should lose their 

 power of capturing their prey. 



163. Adaptations for Protection. In addition to the alter- 

 natives of fighting or fleeing, the animals which are preyed 

 upon have very interesting and effective qualities that make 

 for safety. Many forms, as the Crustacea, have permanent 

 outer coverings; most mollusks have a box arrangement into 

 which they can retire when threatened by attack; others by 

 burrowing or otherwise come to occupy obscure corners in 

 nature where enemies find it difficult to follow. Forms as 

 widely different as the earth-worm, mole, and the chamois find 

 safety in retirement. 



This hiding-theme may be wrought out in ways almost 

 equally effective by what is called protective resemblance. By 

 this is meant that the animal becomes less easily distinguished 

 from its environment because of its color, or form, or both. 

 This resemblance may be to some particular object, or merely 

 a general harmony of color with the surroundings. As illus- 

 trative of the latter head we may cite the quail among the 

 dead leaves and grasses, the sober-hued lizard on the logs, the 

 green caterpillars or tree-toads among the leaves; the tawny 

 color of desert animals, the white fur of arctic forms, the trans- 

 parency of many marine animals. Indeed the great majority 

 of animals show some traces of resemblance to the surround- 



