THE FOOD OF ANIMALS 249 



mature state, make a remarkable change of food. Thus, 

 the tadpole feeds upon vegetable matter ; but the adult 

 frog is carnivorous, living on insects, worms, and 

 crustaceans. 



Many tribes, especially of reptiles and insects, are 

 able to go without food for months, or even years. In- 

 sects in the larval, or caterpillar, state are very vora- 

 cious ; but upon reaching the perfect, or winged, state, 

 they eat little some species taking no food at all, the 

 mouth being actually closed. The males of some roti- 

 fers and other tribes take no food from the time of leav- 

 ing the egg until death. 



In general, the greater the facility with which an ani- 

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

 constant supply. Thus, carnivores endure abstinence 

 better than herbivores, and wild animals than domesti- 

 cated ones. 



