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 Horse 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.—(1) 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 with 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 
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