HOW ANIMALS EAT. 49 



who has been called " the cooking animal." A few of the 

 strictly herbivorous and carnivorous animals have shown 

 a capacity for changing their diet. Thus, the Hoise and 

 Cow may be brought to eat fish and flesh ; the Sea-birds 

 can be habituated to grain ; Cats are fond of alligator- 

 pears ; and Dogs take naturally to the plantain. Certain 

 animals, in passing from the young to the mature state, 

 make a remarkable change of food. Thus, the Tadpole 

 feeds upon vegetable matter ; but when it becomes a Frog 

 it lives on Insects. 



Many tribes, especially of Reptiles and Insects, are able 

 to go without food for months, or even years. Insects in 

 the larval, or caterpillar, state are very voracious; but 

 upon reaching the perfect, or winged, state, they eat little 

 — some species taking no food at all, the mouth being act- 

 ually closed. The males of some Rotifers and other tribes 

 take no food from the time of leaving the egg until death. 



In general, the greater the facility with which an animal 

 obtains its food, the more dependent is it upon a constant 

 supply. Thus, carnivores endure abstinence better than 

 herbivores, and wild animals than domesticated ones. 



CHAPTER VIII. 



HOW ANIMALS EAT. 



1. The Prehension of Food.— (l) Liquids.— The sim- 

 plest method of taking nourishment, though not the meth- 

 od of the simplest animals, is by absorption through the 

 skin. The Tape- worm, for example, living in the intestine 

 of its host, has neither mouth nor stomach, but absorbs the 

 digested food witii which its body is bathed (Fig. 216). 

 Many other animals, especially Insects, live upon liquid 

 food, but obtain it by suction through a special orifice or 



i 



