WAENING- COLOURS 163 



Warning Colours in Reptiles 



Warning characters are not uncommon among 

 poisonous reptiles. The various species of Coral 

 Snake (Elaps), occurring in tropical America, are ex- 

 tremely venomous, and are highly conspicuous, their 

 bodies being alternately banded with bright red and 

 black, and often with yellow. 1 It is extremely in- 

 teresting to observe that the deadly Eattlesnake 

 (Crotalus) warns an intruder of its presence by sound 

 instead of by sight, like the Coral Snake. The Cobra 

 is protectively coloured, but, if attacked, it expands 

 the hood with the conspicuous eye-like marks, and 

 thus endeavours to terrify its enemy by the startling 

 appearance. The majority of poisonous snakes, how- 

 ever, depend entirely upon Protective Resemblance 

 together with the use of their fangs. This, for ex- 

 ample, is the case with our common Viper. 



It is, however, an advantage to some snakes to 

 acquire warning characters and to live on their repu- 

 tation for being poisonous; for although an animal 

 bitten by one of them would probably die, the effects 

 are never immediately fatal, and there would be plenty 

 of time for the snake itself to be killed. Again, the 

 snake possesses only a limited supply of poison at any 

 one time, and if this had been recently drawn upon 



1 See also A. B. Wallace's Essays on Natural Selection, 1875, 

 p. 101. 



