HABITS 97 



thing which others usually refuse to do ; they 

 may, however, be deceived by the dead animal 

 being agitated before them, and the system now 

 adopted in our Zoological Gardens, of offering all 

 snakes previously-killed animals, has been attended 

 with comparative success. 



Some species feed almost exclusively on other 

 snakes, and often manage to swallow individuals as 

 large as, or even a little larger than, themselves. 

 Examples are known of harmless snakes showing 

 a predilection for dangerous species, to whose poison 

 they are immune (see p. 71). 



As a rule snakes that eat fish will also eat batra- 

 chians, but nothing higher in the scale, although 

 exceptions have been reported, such as the Anaconda 

 feeding on mammals, birds, reptiles, and fish, and our 

 Grass-snake having taken mice and birds. Some that 

 feed chiefly on lizards and snakes will occasionally eat 

 also mammals, and vice versa, but rarely frogs. On 

 the other hand, European Vipers accommodate them- 

 selves to a more varied bill of fare, being known to 

 feed on mammals, birds, reptiles, batrachians, insects, 

 and slugs, and they have even been observed to eat 

 voles showing signs of putrefaction. 



The enormous prey which some snakes are able 

 to swallow is quite astounding. Anacondas and 

 Pythons, the largest snakes, have been known to 

 swallow calves and good-sized antelopes with their 

 horns, animals which, even after being somewhat 

 7 



