CHAPTER IV 



FOOD AND GROWTH 



Food. Mode of killing prey. Snake-eating snakes ; egg-eating snakes. 

 Fascination. Rate of growth. Age. Vitality. Regeneration. Chronic disease. 

 Sloughing of skin. Peculiar associations. 



THE food of reptiles is very various ; and while in some 

 groups the nature of the diet is more or less similar in 

 all the species, in other cases there is a remarkable diversity in 

 this respect among closely allied forms. Crocodiles are typi- 

 cally carnivorous reptiles, tearing the carcases of the animals 

 on which they subsist with their powerful and sharp-pointed 

 teeth before devouring them. From the nature of their teeth 

 we may also infer that the typical dinosaurs, such as Megalo- 

 saurus, as well as the theriodonts, belodonts (Phytosaurus), ich- 

 thyosaurs, and plesiosaurs, were likewise carnivorous ; the food 

 of the last two groups probably consisting of the contemporary 

 mail-clad fishes. Such of the pterodactyles as were furnished 

 with teeth were likewise in all probability to a great extent, if 

 not altogether, fish-eaters. And if this be so, we can scarcely 

 refuse to believe that their toothless brethren, in which the jaws 

 were probably sheathed with horn, subsisted on similar food. At 

 first sight, indeed, it may seem strange that this marked differ- 

 ence in the armature of the jaws does not imply a correspond- 

 ing difference in the food ; but the case of the chelonians, in 

 which a toothless horny beak is correlated in some instances 

 with a carnivorous, and in others with a herbivorous diet, seems 

 to negative this idea. For example, while the common green 

 turtle {Chelone my das) is herbivorous, the closely allied hawk- 

 bill (C. imbricata) is strictly carnivorous, feeding upon fishes 

 and molluscs. Again while the land-tortoises (Testudo) are 

 purely vegetable feeders, the common pond-tortoise (Emys orbi- 

 cularis) and some of its near relatives are carnivorous, subsist- 

 ing on fishes, molluscs, worms, insects, etc. On the other hand, 



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