DIFFERENTIATION OF INDIVIDUALS AND ADAPTATION 1 27 



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 fieetness of the other. We can see that these defensive 

 adaptations must in the long run keep pace with the offensive, 

 if both types are to survive,. else the prey would be exterminated, 

 which would entail no less surely the destruction of their ene- 

 mies 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 moUusks have a box-like shell into which 

 they can retire when threatened by attack; others by burrow- 

 ing or otherwise come' to occupy obscure corners in nature 

 where enemies find it difficult to follow. Forms as widely dif- 

 ferent 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- 



