.132 THE SCOTTISH NATURALIST 



meal and regarded the crate as a dark and comfortable corner in 

 which to take up its abode while its meal digested. The latter is 

 more probable, as these snakes do not, as a rule, pursue their prey, 

 but, preferably, lie in wait for it, taking up a position at some spot 

 where the favourite food animal is likely to pass. The Boa lies 

 coiled with the head on top of the coil and the neck part back in an 

 S-shaped loop, as motionless as stone until the prey comes within 

 range, when the head is darted forward with open jaws which grip 

 the head of the prey ; at the same time a coil or two of the snake's 

 body is instantly thrown round the prey which is killed by constric- 

 tion^the pressure of the snake excluding air from the lungs. 

 Sometimes death comes even more quickly through dislocation of 

 the neck of the prey, but in any case it is rapid, and few beasts of 

 prey probably cause less mental or physical pain to the animals they 

 kill than Boas and Pythons. Though snakes of this type feed 

 on either mammals or birds, individually they quickly become 

 habituated to one kind of food, and there is also probably a 

 tendency among the various species to prefer birds only or 

 mammals only. Thus the Indian Python or Rock Snake, which is 

 a much thicker and heavier snake than some other members of its 

 race, though it will feed, at any rate when young, on either birds or 

 small mammals, is a ground-dwelling snake, and prefers furred to 

 feathered prey, and if it has been feeding for any length of time on 

 furred prey alone, will probably starve to death rather than take a 

 bird. The Anaconda, the largest South American snake, and a close 

 ally of the true Boas, is peculiarly subject to what seems mere caprice 

 in its feeding habits, and though young ones can be trained to take rats 

 or rabbits, a snake captured when it is fairly well grown, say a year 

 or two old, will generally refuse to feed on anything but prey similar 

 to that which it has been getting in a wild state. This prey seems 

 to be generally aquatic birds, and Anacondas in captivity will some- 

 times refuse to feed on anything but ducks, and if they cannot have 

 ducks will starve, though surrounded by rabbits, pigeons, and poultry. 



T. H. G. 



{To be cofitiniied.) 



