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VOLE

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Originally appearing in Volume V28, Page 193 of the 1911 Encyclopedia Britannica.
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VOLE , a See also:

book-name (invented by Dr J. See also:Fleming, author of a See also:work on See also:British animals) for the See also:water-See also:rat and those See also:species of See also:field-mice which have cheek-See also:teeth of the same See also:general type. Although the British representatives of this See also:group should undoubtedly retain their See also:vernacular designations of water-rat and See also:short-tailed field-See also:mouse, the See also:term " vole" is one of See also:great convenience in See also:zoology as a general one for all the members of the group. Systematically voles are classed in the mammalian See also:order See also:RODENTIA, in which they constitute the typical See also:section of the subfamily Microtinae in the Muridae, or mouse-group. As a group, voles are characterized by being more heavily built than rats and mice, and by their less brisk movements. They have very small eyes, See also:blunt snouts, inconspicuous ears and short limbs and tails, in all of which points they are markedly contrasted with true rats and mice. In See also:common with lemmings and other representatives of the Microtinae, voles are, however, broadly distinguished from typical rats and mice by the structure of their three pairs of molar teeth. These, as shown in the figure, are composed of a variable number of See also:vertical triangular prisms, in contact with one another by two (or one) of their angles. On the number and relations of these prisms the voles, which See also:form an exceedingly large group, ranging all over See also:Europe and See also:Asia See also:north of (and inclusive of) the See also:Himalaya, and North See also:America, are divided into genera and subgenera. Examples of some of these are afforded by the See also:English representatives of the group. The first of these is the common short-tailed field-mouse, or " field-vole," Microtus agrestis, which belongs to the typical section of the type genus, and is about the See also:size of a mouse, with a short stumpy See also:body, and a Upper and See also:Lower Molars of the Water-Rat tail about one-third the (or Water-Vole), Microtus amphibius. length of the See also:head and body. The See also:hind feet have six pads on their inferior surfaces, and the See also:colour is dull grizzled See also:brown above and greyish See also:white below.

The molar teeth have respectively 5, 5 and 6 prisms above, and 9, 5 and 3 below. This rodent is one of the commonest of British mammals, and frequents See also:

fields, See also:woods and gardens in See also:numbers, often doing consider-able damage owing to its fondness for See also:garden produce. It is spread over the whole of Great See also:Britain (exclusive of the Orkneys), while on the See also:continent of Europe its range extends from Fin-See also:land to North See also:Italy and from See also:France and See also:Spain to See also:Russia. The second and larger species is the water-rat, or "water-vole," which belongs to a second section of the genus, and is commonly known as Microtus (Arvicola) am phibius, although some writers employ the inappropriate specific name terrestris. It is about the size of a rat, and has See also:long soft thick See also:fur, of a See also:uniform grizzled brown, except when (as is not uncommon) it is See also:black. The tail is about See also:half the length of the head and body, and the hind feet are long and powerful, although not webbed, and have five rounded pads on their lower surfaces. In the upper See also:jaw the first molar has 5, the second 4 and the third 4 prisms, of which the last is irregular and sometimes divided into two, making 5. In the lower jaw the first molar has 7 prisms, of which the 3 anterior are generally not fully separated from one another, the second 5 and the third 3. The water-rat is perhaps the most often seen of all English mammals, owing to its diurnal habits. It frequents See also:rivers and streams, burrowing in the. See also:banks, and often causing considerable damage. Its See also:food consists almost wholly of water-weeds, rushes and other See also:vegetable substances, but it will also eat See also:animal food on occasion, in the shape of See also:insects, mice or See also:young birds. The See also:female has during the summer three or four litters, each of from two to seven young.

The range of the water-rat extends over Europe and North Asia from See also:

England to See also:China, but the species is not found in See also:Ireland, where no member of the group is native. The red-backed field-mouse or " See also:bank-vole " may be distinguished externally from the first species by its more or less rusty or rufous-coloured back, its larger ears and its comparatively longer tail, which attains to about half the length of the head and body. On See also:account of an important difference in the structure of its molars, it is now very generally referred to a distinct genus, under the name of Evotomys glareolus; these teeth developing roots at a certain See also:stage of existence, instead of growing permanently. Their prisms number respectively 5 and 4 and 5 above, and 7, 3 and 3 below. The habits of this species are in every way similar to those of the one first on the See also:list. Its range in Great Britain extends northwards to Morayshire, but it is represented in an See also:island off the See also:Pembroke See also:coast by a distinct form; on the continent of Europe it extends from France and Italy to See also:southern Russia, while it is represented in See also:northern Asia and North America by closely allied species. Fossil voles from the See also:Pliocene of England and Italy with molars which are rooted as soon as See also:developed form the genus Mimomys. (R.

End of Article: VOLE

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