CHAPTER XXVI 



ANIMAL DEFENCES— BODILY CHARACTERISTICS 

 PRODUCING CONSPICUOUSNESS 



CONSPICUOUSNESS AS A MeANS OF WARDING OFF ATTACKS. 



Numerous animals are possessed of stings, poison-glands, stink- 

 glands, and the like, which are capable of making them disagree- 

 able or dangerous to their enemies, and many such creatures are 

 practically inedible. But as at close quarters they might be killed, 

 even if not eaten, a device for advertising noxious qualities has 

 been evolved in the form of what is known as warning colora- 

 tion, to which are closely allied certain other warning methods 

 independent of colour-effects. No doubt a considerable number of 

 these conspicuous forms must fall victims to the attacks of inex- 

 perienced aggressors, who, however, taught by experience, are not 

 likely to continue their investigations, so that the warning species 

 is on the whole benefited. And the welfare of the individual is 

 always subordinate to that of the species. 



Warning devices carry in their train a very extraordinary 

 phenomenon, for many perfectly harmless and edible kinds of 

 animal trade upon the evil reputation, so to speak, of warning 

 noxious forms, by coming to resemble these in a very detailed 

 manner. This is technically known as Protective Mimicry, 

 though of course the imitation is a purely unconscious one. 

 Mimicking forms enjoy considerable immunity from attack, by 

 means of sailing- under false colours. It will be most convenient 

 to consider the phenomena involved by warning under two 

 separate headings: Genuine Warning and Spurious Warning 

 (Mimicry). 



GENUINE WARNING 



The best -known cases of such warning are found among 

 lower forms, but one typical case within the class of Mammals is 

 known in the person of the American Skunk (^Mephitis suffocans) 

 (fig. 484), a creature that possesses glands the secretion of which 



