CONCERNING SERPENTS. 



265 



row in the ground, or in clefts of rocks, for their winter sleep. We 

 once saw twenty-six black snakes taken from one burrow beneath the 

 roots of a partially-fallen tree, in February. Other observers have 

 found a much larger number. We are informed that more than 300 

 have been found in a single burro wing-place, and that many species, 

 venomous and non-venomous, sometimes resort to the same rendezvous 

 and hibernate together. In the tropics the anaconda (Fig. 6), and per- 

 haps other species of serpents, sometimes hibernate during the dry 

 season of summer in the hardened mud of dried-up pools. It is by 

 the power to hibernate that serpents survive during the winters of 

 temperate climates, but they seem unable to withstand the extreme 

 and long-continued cold of the arctic zone. There, serpents, and in- 



Fio. 7. 



Northern Rattlesnake. 



deed reptiles of all kinds, are rare, and frequently are entirely wanting. 

 In the Falkland Islands, Terra delFuego, and the mountains of South- 

 ern Patagonia, no serpents have been found. The persistence of 

 vitality in serpents is extraordinary, and continues after great mutila- 

 tions. They are said to have lived several days after removal of the 

 head and viscera. One placed in a vacuum twenty-four hours still 

 showed signs of sensibility ; and, many hours after decapitation, a rat- 

 tlesnake would plunge its headless trunk as in the usual act of striking. 



