326 



PRACTICAL ZOOLOGY 



cause of its habit of trying to frighten an enemy by expanding 

 its neck like a cobra and hissing; and the king snake, which feeds 

 on other snakes, hence its name. 



Constrictors. — There are no very large snakes in North 

 America, but in tropical South America the boa constrictor (Fig. 

 204) reaches a length of eleven feet, and the water boa or ana- 

 conda a length of over seventeen feet. The largest of all snakes 



Fig. 204. — Boa constrictor. (By permission. Copyright by Sturgis and 

 Walton Co.) 



is the regal python of Burma (Fig. 205), which may grow to be 

 thirty feet long. All of these large snakes are constrictors ; that 

 is, they capture birds and mammals and squeeze them to death 

 in their coils. Very few of them are dangerous to man. 



Poisonous Snakes. — The only poisonous snakes in this 

 country are the rattlesnakes, copperhead, water moccasin, 

 harlequin snake, Sonoran coral snake, and a few small species in- 



