ANIMAL DEFENCES 



CHAPTER XXV 



ANIMAL DEFENCES — INTRODUCTORY— BODILY CHARAC- 

 TERISTICS PRODUCING INCONSPICUOUSNESS 



Considerable space having just been devoted to the question 

 of food and feeding, it may prove interesting to briefly review 

 the chief ways in which animals evade or escape from the attacks 

 of more powerful or more destructive forms. Protective devices 

 are numerous and often very elaborate, but none of them attain 

 more than partial success, for the evolution of some particular 

 line of defence is sure to be associated with methods of offence 

 which neutralize its value to a greater or less extent. An in- 

 structive analogy is found in the arts of war, where attack and 

 defence develop side by side, any advance in one quickly leading 

 to corresponding progress in the other. In war the penalty of 

 inadequate defence is defeat, among animals it has often led to 

 gradual decrease in numbers frequently resulting in complete 

 extinction, which is of course the most ignominious kind of failure 

 in the struggle for existence. Survival of the fittest is associated 

 with non-survival of the unfittest. As we shall have occasion 

 to note elsewhere, there are many unfavourable elements to be 

 combated in this struggle, though we are here concerned only with 

 defence against predaceous forms on the look-out for a meal. 

 But herbivorous species have not only to meet this kind of direct 

 attack, but also to cope with other species which live on the same 

 kind of food, of which only a limited quantity is commonly avail- 

 able, and unfavourable conditions of climate, &c., have also to be 

 taken into consideration. In discussing defensive measures it is 

 difficult, if not impossible, to avoid language which seems to 

 attribute conscious effort or knowledge on the part of this or that 

 kind of animal, but under a great many of the headings employed, 



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