1302 THE RODENTS 



livers, being not ttnfrequent in water meadows, and occasionally in plowed fields 

 at a considerable distance from the water. Although the water vole has been 

 accused of carnivorous propensities, it is very doubtful if the charge can be sub- 

 stantiated. Its favorite food in summer appears to be the sweet inner pith of certain 

 kinds of water flags, but it will also eat many other aquatic plants, such as duck- 

 weed and horsetails. In winter, when hard pressed for food, the water vole turns 

 its attention to the bark of trees and shrubs, and at this season frequently inflicts 

 very serious damage on osier plantations. In cultivated districts it will also then 

 readily eat mangold, turnips, potatoes, etc. When feeding upon duckweed, Bell 

 says that " the creature sits, like a squirrel, on its haunches, near the water's edge, 

 and, taking up a lump of the soft and slimy-looking mass in its fore-paws, eats a 

 small part only, and, letting the remainder fall, takes up some more, which is 

 similarly treated and rejected." 



In May or June, and occasionally as early as April, the female gives birth to 

 five or six young in the depths of its burrow, and it is probable that when the 

 litter is produced early in the spring, a second one follows during the summer. 

 When their holes are rendered inaccessible by frost, water voles are found to take 

 shelter on shore, sometimes frequenting the cover afforded by an osier bed, and 

 on other occasions taking refuge in pollard willows. In spite of its feet not being 

 webbed, the water vole is an expert swimmer and diver, and its coat is of a such a 

 nature as to throw off the water as readily as does the plumage of a duck. Fossil 

 remains of the water vole are found in the cavern deposits of England, and also in 

 the "forest bed" of the Norfolk coast, while those of extinct species of the genus 

 to which it belongs, occur in the Pliocene crag deposits of Suffolk and Essex. 



In addition to the water vole, the British Islands (exclusive of Ire- 

 Short-Tailed * A \ ,1 r ,, - 

 land) possess two other species of the same genus, the commonest of 



which is the the short-tailed field vole, or field mouse (M. agrestis). 

 This species is about the size of an ordinary mouse, and is grayish brown in color 

 above, and grayish white beneath, with dusky feet; the tail being about one-third 

 the length of the body, while the under surfaces of the hind-feet have six naked 

 pads. It is specially characterized by the circumstance that the second molar tooth 

 in the upper jaw has five prisms. This character, unimportant as it may seem, 

 serves to distinguish this species from the continental field vole {M. arvalis} repre- 

 sented in the accompanying illustration in which, in common with the other con- 

 tinental short-tailed members of the genus, the corresponding tooth has but four 

 such prisms. 



The common short-tailed field vole is found all over England and Scotland, as 

 well as the greater part of the Continent; its range extending from the north of 

 Italy to Finland, and from Spain and France to Russia; but in the southern portion 

 of its habitat it is less numerous than the continental field vole. The English 

 species is commonly found in meadows especially those where the ground is 

 moist, and makes extensive runs beneath the grass, in which it roams both by night 

 and day, although it is more active during the dark hours. In addition to these 

 runs the field vole also constructs burrows of considerable size. The food of this 

 species consists of seeds, roots, and herbage of all kinds. In gardens it displays an 



