FISHES, BATRACHIANS, AND REPTILES 



225 



and in many cases serve to produce an effective protective 

 resemblance by harmonizing with the usual surroundings 

 of the animal. The food of snakes consists almost ex- 

 clusively of other animals, which are caught alive. Some 

 of the poisonous snakes kill their prey before swallowing 

 it, as do some of the constrictors. While most snakes 



Fig. 184. — A garter-snake, Thamnophis parietalis. (Photograph from 

 life by J. O. Snyder.) 



live on the ground, some are semi-arboreal and others 

 spend part or all of their time in the water. Cold- 

 region snakes spend the winter in a state of suspended 

 animation ; in the tropics, on the contrary, the hottest part 

 of the year is spent by some species in a similar " sleep." 

 Among the commonest members of this group are the 

 garter-snakes (fig. 184), always striped, and not more than 

 three feet long. The mostwidespread species is rather dully 

 colored, with three series of small dark spots along each 

 side. The common water-snake is brownish, with back 

 and sides each with a series of about eighty large, square, 

 dark blotches alternating with each other. It feeds on 

 fishes and frogs, and, although unpleasant and ill-tem- 

 pered, is harmless. One of the prettiest and most gentle 

 of snakes is the familiar little green-snake, common in the 

 East and South in moist meadows and in bushes near the 

 water. It feeds on insects, and can be easily kept alive 



