360 



GENERAL ZOOLOGY 



mostly in the arid regions of the West and Southwest. The 

 use of the peculiar horny appendage, or rattle, at the end of 

 the tail of the rattlesnake has occasioned much discussion. 

 By some it has been thought to be a means of terrifying 

 its prey, so that escape may be rendered impossible; by 

 others it has been regarded as a sex call for its mate, or 

 even as a lure for birds. Many naturalists consider that 



/ 



.'. 



Fig. 186. Coral snake 

 Photograph by courtesy of the American Museum of Natural History 1 



its function is similar to that of the yellow and black colora- 

 tion of wasps, or the distinctive red markings of poisonous 

 spiders, — features which serve to mark the possessor as 

 having unusual means of defense. It is thought many con- 

 flicts are avoided which might prove disastrous to the rat- 

 tlesnake, even if the attacker were killed in the contest. As 

 it is, an animal must have some confidence in its powers if 

 it disregards the warning rattle. A diamond-back rattle- 

 snake in captivity in the New York Zoological Park grew a 

 new "button" to the rattle every three months, on each 

 occasion of shedding its skin. 



1 From R. L. Ditmar's Reptiles of the World, with the permission of The 

 Macmillan Company. 



