434 



PRACTICAL ZOOLOGY 



and vegetables are carried in the pouches, and such quantities 

 are destroyed as to make these rodents quite injurious to crops. 



FIG. 302. Pocket gopher. (Photo, by Hegner.) 



The rat family includes the muskrats, lemmings, meadow mice, 

 white-footed mice, and rats. About one-fourth of our mammals 

 belong to this family. They are all small, the muskrat being one 

 of the largest American species. The common house mouse, the 

 Norway rat, and black rat have all been introduced into this 

 country from the Old World. 



The members of the porcupine family are characterized by the 

 presence of spines, which normally lie back, but can be elevated 

 by muscles in the skin (Fig. 303) . 



Toothless Mammals. - - The toothless mammals are mainly 

 inhabitants of South America. The anteaters possess a long, 

 narrow snout, and are provided with long claws on the fore feet 

 which are used to tear open ant hills. The tongue is long and 

 slender and serves to capture the ants upon which the animals 

 feed. 



