i6 



THE SNAKES OF SOUTH AFRICA. 



tongue. I have satisfied myself of this on many occasions, by 

 observing captive snakes. At these times when touched, snakes 

 lunge out \vildly with gaping jaws, but owing to their semi-blind 

 condition their aim is not accurate. 



When molested, a snake darts out and vibrates its tongue, 

 evidently with the purpose of intimidating its enemy. 



Snakes shed the outer layer or horny Epiderm of the skin 

 several times annually, differing in frequency with the species, 

 and the abundance or otherwise of food. Captive snakes which 

 refuse all food, usually moult only once, although they may 

 survive a year before dying ultimately of starvation. The 



Fig. 9. — Cast skin of head and neck of snake. Note inverted eye scales, like watch glasses 



with concave side uppermost. 



moulting process usually begins a few days after birth and con- 

 tinues throughout life. The skin peels off more or less entire. 



The shedding or casting of the old skin begins at the lips. 

 The skin around the mouth curls up, and by pushing itself against 

 twigs, crawling through tufts of grass, etc., the snake gradually 

 draws itself right out of its skin. This comes off inside out, like 

 a tight glove being pulled off the hand from the wrist portion. 



The cast skin is often perfect, without a crack, tear, or loss of 

 a single scale — even the transparent eye scales come away. The 

 main reason why snakes cast their skins is to provide for increased 

 growth. The skin of a snake does not grow with the growth of 



