52 ZOOLOGY. 



time ; their haunts are on the banks of extensive lakes or 

 rifers, far from the habitation of man. It is not a little 

 curiousj that their ingenuity seems entirely to quit them, or at 

 least to lie dormant unless in society, as individuals or 

 pairs, do not attempt even to burrow, when in their wild 

 state. Their skins are among the most valuable of furs ; 

 besides which, they are hunted for the sake of a secretion 

 contained in glands situated beneath their tails, and which it 

 the Castor of the shops. 



4. Mas. Rat. Upper front teeth wedge-shaped ; grinders 

 three, rarely two, on each side of each jaw ; clavicles 

 perfect. 



This numerous genus is widely extended, but few places 

 being without some species or other* some burrow in the 

 ground where they lay up provision for the winter, others 

 seek holes in roeks and trees for the same purpose, several 

 species attach themselves to man, and live entirely on his 

 labours ; some kinds become dormant or torpid during 

 winter. 



Their food is various, as fruit, roots, grain, flesh, crabs, and 

 many of the smaller quadrupeds, even of their own kind ; 

 also young poultry, eggs, and in fact some of the species will 

 devour almost every description of animal substance : some 

 are migratory, and others nearly amphibious ; they are 

 all extremely prolific, often producing eight to twelve at a 

 birth, and this several times in the year, they are devoured 

 by their own kinds, the Fox, Cat and Weesel tribes, as 

 also by Birds of Prey, Snakes : and the aquatic species ar« 

 destroyed by Pike and other predaceous fishes. 



