REPTILIA 



559 



The small, conical head and slender, cylindrical body of the coral 

 snakes fit them for their subterranean life. They seldom come to 

 the surface during the day, but may be found at night crawling 

 about in search of food. They eat other snakes and small lizards. 

 These snakes lay eggs. 



Family Hijdrophidae.— Members of this family are marine relatives 

 of the Elapidae. Only one species is found in the New World. It 

 occurs off the west coast of Mexico and has been reported as very 

 common in some localities at certain seasons. The females come 

 into shallow coastal waters to give birth to their young. Here the 

 young have some protection from their enemies and access to small 

 fish suitable for food. Adults of Old World species have been 

 sighted one thousand miles from land. All species have the tail 

 flattened for swimming. 



Family Croialidae (pit vipers).— This family is composed of six 

 genera which contain about eighty species. Members of the family 

 are found over all the temperate and tropical parts of the Western 

 Hemisphere. In the Old World they are found in India, China, and 

 neighboring regions. 



Three of the six genera in the family have representatives in the 

 United States. In fact, all the dangerously poisonous snakes in 

 this country, except the coral snakes, belong to this family. They 

 are all solenoglyph snakes. There is a prominent pit on each side 

 of the head between the eye and the nostril. The rattlesnakes 

 (Crotahis and Sistrurus) bear rattles on the end of the tail. All 

 members of the family have elliptical pupils. 



The poison glands and highly developed fangs enable these snakes 

 to capture their food with a minimum of effort on their part. The 

 venom is injected so quickly and so unexpectedly that the prey has 

 little chance to avoid it. Most small animals die very soon after 

 being bitten. The reptile then swallows the carcass at its own 

 pleasure. Rattlesnakes prefer mammals. In regions where these 

 snakes abound wild rats and mice are rare. Water moccasins take 

 frogs and other cold-blooded aquatic animals for food. The cop- 

 perhead appears to enjoy both warm-blooded and cold-blooded 

 animals. 



All members of this family give birth to living young or lay thin- 

 shelled eggs which hatch in a very short time, usually less than 

 an hour. 



