CARNIVOROUS AND INSECTIVOROUS REPTILES 73 



LIZARDS 



The large and widely-distributed order of Lizards is in the 

 main an assemblage of carnivorous species, most of which are 

 suited to a life on land. All sorts of animals serve as food, from 

 small backboned animals down to insects, snails, and worms. Our 

 native species are typical representatives of an Old World family 

 rich in species, of which the chief food is insects. Extreme agility 

 and the possession of numerous small, pointed teeth are obvious 

 attributes, both of which appear to be related to the nature of the 

 food. 



The Monitors constitute a group of large Lizards ranging 

 from Africa through the south of Asia into the Australian region, 

 and feeding upon various backboned animals, such as frogs, 

 reptiles, birds, and small mammals. As might be expected from 

 the nature of the food, the teeth are large and pointed. The 

 different species live in very different surroundings, and exhibit 

 specializations of corresponding kind. The Desert Monitor 

 ( Varanus griseus) inhabits the deserts of North-west Africa and 

 South-west Asia, and is rendered inconspicuous in its natural 

 surroundings by its dull coloration. The powerful cylindrical 

 tail is used as a weapon. The Papuan Monitor ( V. prasinus) 

 is believed to live among trees, and its tail is shaped like that 

 of the last-named species. Most of these Lizards, however, 

 have tails which are strongly flattened laterally, a feature usually 

 associated with the power of swimming. An example is the Nile 

 Monitor ( V. Niloticus) (see vol. i, p. 224), which frequents most of 

 the African streams, and preys largely upon the eggs of crocodiles. 

 And as a last example we may take the Water Monitor ( V. sal- 

 vator), which is the largest of the series, attaining a length of 

 pretty nearly 7 feet. Its range extends through South Asia to 

 Australia, and it is mostly found in marshy ground in the neigh- 

 bourhood of water, both salt and fresh. Not only can the animal 

 swim, but also climb among trees, devouring smaller lizards and also 

 birds, as well as the eggs of the latter. It has a curious method 

 of egg-eating, for an Q.<g^ is first seized in the jaws, the head is 

 turned up, and the egg-shell broken with the teeth in such a way 

 that the contents can be readily swallowed. 



Among the most interesting climbing lizards are the small 

 insect-eating forms known as Geckoes and Chameleons. Geckoes 



