KEPTILES 327 



Poisonous snakes. Fortunately none of our venomous 

 snakes tend to infest houses, as does the hooded' cobra of 

 India. In consequence, snake bites are extremely rare with 

 us, and probably not more than two deaths occur annually 

 from this cause (Hornaday). Of the 17 venomous species 

 13 are rattlesnakes, belonging to the genera Crotalus and 



FIG. 160. Blowing viper, trying to make room for one more 

 Photograph by the author 



Sifstrurus (the massasaugas), so well known, so clearly dis- 

 tinguished by the rattles, and so nearly extinct from all 

 sectled regions, that they require no description. It is proba- 

 bly safe to say that a rattlesnake strikes only in self-defense 

 and that it never gives chase. When coiled it cannot strike 

 more than one third of its length, and much less if the neck 

 is drawn into an S-shaped loop, and its rasping buzz gives a 

 warning that is readily understood by both animals and man. 



Closely related to the rattlesnakes are the two moccasins the 

 lip Land moccasin, or copperhead (Ancistrodon contortrix), and the ugly 

 wiiter moccasin (A. piscivorus), often called the cottonmouth. The 

 copperhead is found among rocks and in woods from Massachusetts 

 to Florida, ranging westward to Texas and northward to Indiana. The 

 wsiter moccasin inhabits the swamps and grassy shores of the bayous 

 of the Gulf states, feeding largely on fish and frogs, and on other snakes. 



