356 



GENERAL ZOOLOGY 



impossible ; by others it has been regarded as a sex-call for 

 its mate, or even as a lure for birds. Many naturalists con- 

 sider that its function is similar to that of the yellow and 

 black coloration of wasps, or the distinctive red markings of 

 poisonous spiders, features which serve to mark the pos- 

 sessor as having unusual means of defense. By the mere 



FIG. 182. Photograph of Blacksnakes 



fact of this advertisement it is thought many conflicts are 

 avoided which might prove disastrous to the rattlesnake, 

 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 and tries conclusions with 

 the owner. A diamond-back rattlesnake 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. 



