80 SKETCH or THE HISTORY OF MAMMALIA. 



stables, &r., making deep burrows in which to rear its 

 young. From this pest the water-rat is totally distinct. 

 It frequents the borders of large ponds, reservoirs, 

 streams, and rivers, dwelling in burrows of considerable 

 extent, to which there are generally two or more outlets. 

 The main outlet is in most instances close to the water's 

 edge, so that during floods it is not unfrequently below 

 the surface, but the gallery, sloping upwards as it pro- 

 ceeds in the bank, terminates in a chamber which the 

 water does not reach. Here, in a snug bed of dried 

 grass and vegetable fibres, the female rears her young. 

 Nocturnal or crepuscular in its habits, it is chiefly as the 

 dusk of evening steals on that the water-rat emerges from 

 its retreat, but it seldom ventures far from the margin of 

 the pond or river, into which when alarmed it imme- 

 diately plunges, and swims under the cover of overhanging 

 roots and herbage to its burrow. Though not web- 

 footed, it is at home in the water, and dives with great 

 ease. There are few persons who have not noticed its 

 waymarks on the surface of stagnant ponds or ditches 

 mantled over with a thick crop of chickweed. These 

 tracks are made during the night, the season in which it 

 wanders in search of food or its fellows. The roots of 

 aquatic plants, especially the typha, the stems of equi- 

 setum, buds and bark, &c., constitute the diet of this 

 species : it has been affirmed that it feeds also upon insects, 

 small fishes, frogs, &c., but for this assertion there is 

 not the slightest foundation. It would appear that the 

 water-rat hybernates during some portion of the winter, 

 and also lays up a store of food, Mr. White says, '* As 

 a neighbour was lately ploughing in a dry chalky field, 

 far removed from any water, he turned out a water-rat 

 that was curiously laid up in an hybernaculum artificially 

 formed of grass and leaves. At one end of the burrow 

 lay above a gallon of potatoes regularly stowed, on which 

 it was to have supported itself for the winter," It must 

 be acknowledged that there are some points in the his- 

 tory of this species to be cleared up. In size this animal 

 equals the common brown rat, but the head is thicker 

 and more obtuse, the muzzle being blunt and short ; the 



