CHAP. V. DEFENCES OF ANIMALS. 127 



(151.) The power of defence enjoyed by animals 

 against their enemies is obviously given to them for 

 self-preservation, and is peculiarly adapted to meet 

 those exigencies which every species, either by its eco- 

 nomy or its structure, is more especially exposed to : 

 hence, we might almost say that these powers or pro- 

 perties are infinite, inasmuch as their modifications are 

 innumerable. They seem, however, to be all referable 

 to three great classes. The first are active : these con- 

 sist in the exertion of force, by which assaults are made 

 by weapons or instruments possessed by the animal itself, 

 and requiring his active exertion in their use ; and such 

 powers may obviously be employed either in offensive 

 or defensive warfare. The horns and the teeth of 

 quadrupeds, the stings and jaws of insects, and the 

 poisonous fangs of reptiles, are of this description ; for 

 none of these would be conducive to the purposes for 

 which they were given, without the voluntary exertion 

 of their possessor. The second class of defences are 

 strictly passive ; they are as effectual, in most cases, as 

 the first, but they require no exertion of the animal to 

 bring them into operation. We accordingly find that 

 it is generally to the weakest and most helpless beings 

 that these protections are given. The thick hide of the 

 elephant protects him from those hosts of blood -sucking 

 flies which are the pest of tropical climates. The spiny 

 hides of the hedgehog and the porcupine, the stinging 

 hairs which envelop many caterpillars, and the dis- 

 gusting stench from the body of the turkey vulture, 

 are a few out of innumerable instances of that passive 

 defence we are now speaking of. But there is still 

 another property, which will by no means come under 

 either of these definitions, although it has obviously 

 been bestowed with the same merciful design ; we allude 

 to that astonishing vitality possessed by such beings as 

 are most exposed to injuries, and by which life is not 

 only supported without food for an amazing length 

 of time, but dislocated portions grow and become new 

 animals. These wonderful phenomena will be treated 



