Products of Glands with Ducts 



as fast as it passes from the small intestine to the rectum. Other animals and 

 human infants automatically throw off the refuse from time to time. 



What Do Other Kinds of Animals Do with Food? 



Kinds of Feeders The digestive system in the human body disposes 

 of the proteins, carbohydrates, and fats from a great variety of sources- 

 plants and animals of many different kinds. Animals are of course re- 

 stricted in their diet by what happens to be present in their immediate sur- 

 roundings. But many species are limited also by their natural equipment 

 for making the food available. The cow eating grass, for example, dis- 

 regards the flies which are gobbled up by the frog not far away. The crow 

 eats worms and grubs and the seeds of many plants. The squirrel in the 

 same region concentrates on nuts. Some animals kill others and devour 

 them without special preparation. Snakes and owls swallow their prey 

 whole, digest what is usable out of the mass, and eventually reject the bones, 

 hide and hair. Related to the many ways of getting food, to the kind of 

 food obtained, and to the conditions of food-getting, are the distinctive di- 

 gestive systems of various species of animals. 



Chewing at Leisure Several of the even-toed ungulates, or hoofed 

 animals, such as cows, sheep, goats, antelopes, deer, giraffes and camels, 

 browse until they have filled their first stomach, the rumen, with unchewed 

 roughage composed of grass and other vegetation. They then lie down in 



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