THE FOOD OF THE OTHER LAND ANIMALS Ss 



large maximum, though at the same time permits only a 

 relatively large minimum, size, find themselves existing in a 

 world abounding with vegetation upon which directly or 

 indirectly countless hordes of insects live, together with snails 

 and slugs and earth-worms and, near the water, crabs. Other 

 animal t>'pes are in negligible quantity and keep themselves 

 hidden from sight. 



Their large size and great muscular power enable the land 

 vertebrates to ignore the insects as competitors for the vege- 

 tation, as well as to utilize them, the earth-worms, the snails 

 and the crabs as food. One curious fact in regard to the 

 vertebrates is that the less perfected types are all, or nearly 

 all, carnivorous, plant-eating forms being found only among 

 the more specialized. 



The amphibians — frogs, toads, salamanders, etc. — like the 

 fishes are almost exclusively carnivorous, feeding on insects, 

 slugs and worms, while the very large toads will even devour 

 young chickens and mice. But the tadpoles of some of them 

 for a greater or lesser period feed on algae and plant remains 

 in water, and the curious Siren is strictly vegetarian. A 

 few are worm or snake-like and live underground, while others 

 live in caves deep under ground and, blind themselves, like 

 the blind fish feed on blind crustaceans None are marine. 



The great majority of the lizards are carnivorous, the larger 

 feeding on small mammals, birds, fishes and eggs, the smaller 

 on insects, worms and other invertebrates; but a number are 

 herbivorous, as the larger iguanas and many agamids. One 

 iguana, the only lizard that can be called marine, though 

 living on land in the Galapagos Islands feeds beneath the 

 water on sea-weed. A number of lizards of different groups 

 are limbless and snake-Uke, some of these living underground 

 like worms. The crocodiles, alligators, caymans, and their 

 allies are all carnivorous. Some American crocodiles are ma- 

 rine, the others living in fresh water. 



All the snakes are carnivorous. The burrowing snakes, which 

 live underground and are small and never poisonous, feed on 



