HIBERNA TION. 163 



activity and disinclination for food as early as September 

 if the season be unusually cold, at other times in October ; 

 but, on the contrary, during a milder season they keep 

 active until November, while some do not hibernate 

 at all. Their habits there can, however, scarcely 

 be cited as normal, since the artificial heat regularly 

 maintained in the Ophidarium never permits the rigours 

 of an out-door winter to affect them. Nevertheless they 

 manifest the disposition for repose ; and if it could be 

 so arranged that the tropical snakes could be submitted 

 to tropical heat and drought, and those of cooler countries 

 to frosty air, as in a state of nature, we might witness 

 both estivation and hibernation under the same roof. 



A partial hibernation is observable in reptiles in captivity 

 when, though not absolutely inactive, they decline food. For 

 twenty-two weeks a python at the Zoological Gardens fasted 

 during one winter ; at another time, twenty weeks. The large 

 python {reticidatus) fasted for one year- and eleven months, 

 covering two winters, but fed well and retained its health 

 after this. Meanwhile, during this prolonged fast, should a 

 gleam of sunshine penetrate the foggy atmosphere of our 

 London winters, and shine through the glass roof upon a 

 constrictor's coverlet, he may slowly emerge therefrom, dis- 

 playing a few feet of his lazy length for an hour or so, thus 

 verifying the words, ' obedient to the external atmosphere.' 

 No creatures are so susceptible of the changes of temperature ; 

 and the same degree which caused them to seek a retreat 

 will, on the return of spring, reanimate them. And warmth — 

 in them almost another word for vitality — equally affects their 

 appetite. In the very height of summer, should their feeding- 



