470 THE SNAKES OF SOUTH AFRICA. 



All the Viper and Cobra Family of snakes are venomous. 



One of the Viper snakes of South Africa has taken to burrowing in 

 the ground. In consequence, its body has become quite round (cylindrical) . 

 The poison glands of these snakes are situated one on each side of the head. 



These glands manufacture the venom and store it up. 



When a snake bites, certain muscles wring the poison glands, causing 

 the venom to run through a narrow channel, and down the hollow or 

 grooved fang. 



The Night Adder of South Africa is a remarkable exception to the 

 general rule. Its poison glands extend for about three inches down its 

 back. They lie on each side of the backbone, as seen in the illustration. 



Snakes eat rats and mice in great numbers. Rats and mice breed 

 very quickly, and would soon become a great plague to us if their numbers 

 were not kept in check. 



The Mole Snake and House Snake are quite harmless. They are both 

 good rat-catchers. They are our friends, and should never be killed. 



Some snakes swallow eggs whole. They cannot suck eggs. 



The stomach juices dissolve the shell and release the contents. 



The Dasypeltis or Egg- eater Snake of South Africa has teeth in its 

 backbone. These are its saw. It swallows an egg, saws the shell, and 

 spits it out. 



Snakes have many natural enemies. Mungooses, Meercats. and 

 Muishonds eat them. So do most of the birds of prey. 



Most snakes are cannibals. They not only eat those of other species, 

 but of their own too. 



Snakes do not chew their food. It is swallowed whole. 



Snakes do not cover their prey with saliva before starting to swallow it. 



Saliva runs abundantly into the mouth during the swallowing process, 

 and lubricates the prey as it passes down the throat. 



When injured or alarmed, a snake will usually disgorge anything it 

 may have swallowed. 



Pythons, Mole Snakes, House Snakes, and some other kinds of non- 

 venomous snakes kill their prey by throwing two or more coils round it, 

 and crushing it to death. 



Venomous snakes never constrict their prey. They kill or paralyse it 

 with their venom. 



The forked tongue of a snake is not its sting. The tongue is very 

 sensitive and acts as a feeler, like the tips of your fingers, or a cat's whiskers. 



Most snakes live upon the ground, although the majority can climb. 



Others live almost entirely in trees. They are known as arboreal or 

 Tree Snakes. 



Some kinds of snakes live entirely in water. All the Sea Snakes live 

 in the ocean, and feed on fish and other marine creatures. 



The Sea Snakes are all poisonous. They have a flattened oar- like tail 

 for propelHng themselves through the water. They breathe air like other 

 snakes. 



