Boa- Constrictors of British Guiana. 301 



the sight of a snake's approach is in no case different from 

 the corresponding manifestation of profound fear and collapse 

 on the part of many animals in the presence of extreme 

 danger. 



In the case of rats, at any rate, there is not only no sign of 

 any such fear ; but they even appear to be more than callous, 

 often attacking and badly biting the snakes if the latter be not 

 hungry, and rendering their removal necessary. 



The instances of the two snakes — one a land-boa and the 

 other a water-boa — naturally eating dead animals placed in 

 their cages appear to be quite exceptional, for in other speci- 

 mens such consumption was only brought about by strategy. 



Properly fed and taken care of the water-boa and the land- 

 boa also become extremely quiet and gentle — perhaps, more 

 truly, sluggish — in their movements ; and a large specimen of 

 the former, over 20 feet in length, manifested in confinement 

 not the slightest inclination, nor made the slightest attempt, 

 to attack when disturbed, or even when quietly handled. 

 These reptiles are nocturnal in their habits, and when they 

 have the chance seek out dark corners in which to shelter 

 themselves from the light. 



When these snakes have become accustomed to a special 

 diet, such as rats, for instance, they seem at times to neglect, 

 even when they are in want of food, other creatures that at 

 first they would have seized upon at once. Thus a large 

 Salempenta or Teguexin lizard has remained for years in a 

 cage with a water- boa, unmolested, even when the latter has 

 been hungry, and has taken four large rats in succession. 



It is a common belief that the boas lubricate their prey 

 before swallowing it. There is really not the slightest 

 foundation for the belief. After the object is dead the snake 

 usually passes its head along or about the body, perhaps to 

 get some idea of the size, but more likely to find the situation 

 of the head, at which part it almost invariably starts to 

 swallow. At this stage there is no saliva on the object; but 

 if, after it is partly swallowed, it has to be rejected on account 

 of too great size, that part of the body which had been in the 

 snake's mouth and throat will be found to be abundantly 

 covered with the saliva poured out during the process of 

 swallowing. In confinement, at any rate, it not unfrequently 

 happens that objects are thus disgorged after being nearly 

 taken down ; and it would seem to be due to their being too 

 large, the snakes attempting, through hunger, to prey upon 

 what ordinarily, in nature, would be left alone. The saliva- 

 tion therefore is not the preliminary to swallowing, but the 

 result of it. 



