44 THE SNAKES OF SOUTH AFRICA. 



with the cold, but on the apphcation of heat they soon regained 

 all their vigour and vitahty. 



The live snakes at the old Port Elizabeth Museum cages were 

 most active when the air is warm, and grew torpid in propor- 

 tion to the lowering of the temperature of the air. When their 

 cages were artificially heated they immediately revived. 



If a snake should find a cosy retreat, and provided there is 

 sufficient sustenance in the neighbourhood, he will make that 

 spot his headquarters, from which he will issue forth when hungry 

 and scour the neighbourhood in search of food ; or else bask in 

 the warm sunshine ready to beat a retreat on the least sign of 

 danger. When the leaves begin to fall and the air grows chilly, 

 a drowsy feehng begins to pervade his body which warns him it 

 is time to seek out a cosy shelter for his long sleep. So he crawls 

 into the innermost recesses of his lair, or seeks out a better one. 

 Coihng himself up, he sinks into a condition of torpor. 



Many species of reptiles have the power of suspending anima- 

 tion and lying in a death-like trance through the winter months, 

 when the food on which they live is either very scarce or quite 

 unobtainable. When animation is more or less suspended, an 

 exceedingly small quantity of food-material is used up to keep 

 the creature alive ; whereas if it were active all the winter, it 

 would require an abundant supply. This would mean that most 

 species of reptiles would die of starvation. Those which had found 

 enough food to tide them over till the summer season would not 

 be in sufficient numbers to keep down the armies of living creatures 

 which constitute the diet of reptiles. Thus the balance of Nature 

 would be upset. 



Parasites on Snakes. 



Snakes are frequently infested with parasites. Ticks often 

 fasten themselves upon the skin between the scales. 



There once occurred an unusual mortality amongst the collection 

 of live snakes at the Port Elizabeth Museum, which are kept in 

 a long row of cages each four feet square and the same height, 

 with plate-glass on the four sides. Noticing minute parasites 

 upon one of the dead snakes, I made a microscopical examination 

 of them, and found they were a species of lice somewhat smaller 

 than fowl lice. On close observation of the Hving snakes I 



