The Continent of Europe is inhabited by several other species of Voles, among which we may notice the little SOUTHERN FIELD VOLE (Arvicola arvalis), which more or less completely takes the place of our common Field Vole in Southern Europe, but also extends over the whole of Central Europe, and into Western Asia. Several of these species, and others to which we cannot specially refer, ascend to considerable elevations on the mountain-sides, but at least one species, the SNOW MOUSE (Arvicola nivalis), lives on the Alps and Pyrenees, at elevations of 4,000 feet and upwards, being most abundant about the limit of perpetual snow, where it not only resides during the short period of summer, when some portion of the surface is freed from its snowy covering, but actually throughout the winter, buried under the snow, through which it makes its way in search of the roots of plants. The ROOT VOLE (Arvicola œconomus) is a large and abundant Siberian species, the range of which extends from the Obi to Kamstchatka. This and some other northern species often migrate in great bodies, after the fashion to which we shall have to refer when speaking of the Lemmings.
In North America, it would appear from Dr. Coues’ monograph, there are about a dozen distinct species of Voles. One of them, confined to the northern parts of the Continent, he identifies with the Arvicola rutilus of the Old World, which he regards as a circumpolar species. South of a line running from sea to sea, a little north of the boundary of the United States, comes another form, A. Gapperi, which is regarded as a sub-species of A. rutilus, to which A. glareolus (see p. 116) is considered to stand in a similar relation. The most abundant North American species is the MEADOW MOUSE (A. riparius), which is distributed, apparently, over the greater part of the Continent, and takes the place of the Field Vole. On the prairies there is a peculiar species (A. austerus), a sub-species of which (A. curtatus) is found in the Western territories as far as California; the PINE MOUSE (A. pinetorum) inhabits the country east of the Mississippi; and the genus is represented in Mexico by one species (A. quasiater). The Voles are most numerous and abundant in the northern and north-western parts of North America.
Another American species is the MUSQUASH, MUSK-RAT, or ONDATRA (Fiber zibethicus), which constitutes a genus distinguished from the true Voles by having the tail compressed and nearly naked, the hinder toes united by short webs, and fringed with long hairs, and the enamel folds of the molars united by a line running down the middle of the tooth. The form of the animal is thickset, and in this respect, as in its aquatic habits, it resembles the Beaver, to which it was formerly supposed to be nearly allied. The head is short and broad, the ears project very little beyond the fur, the hind limbs are longer than the fore legs, and terminate in five toes with strong claws, while the fore limbs have only four toes and a wart-like thumb; the fur is very thick and shiny, and the colour is usually brown above and grey below, with the tail, which is nearly as long as the body, black. The fur is well known in commerce. The length of the head and body of a full-grown male is about twelve inches. The name Musk-rat, often given to this species, refers to the musky odour diffused by the secretion of a large gland situated in the inguinal region.
The Musquash, which may be described as a large Water Rat, inhabits all the suitable parts of North America, from the thirteenth to the sixty-ninth degree of north latitude, and is most abundant in the Canadian region, which offers it peculiarly favourable conditions of life in the multitude of rivers and lakes, upon the banks of which the Musquash always takes up its abode. It is a nocturnal animal, passing the day in concealment, and coming forth with the twilight to seek its nourishment, and amuse itself with its fellows. In the water it displays wonderful activity, and, in many respects, presents much resemblance to the Beaver. Curiously enough, the parallelism of habits holds good to a certain extent, even in the construction of their dwellings. The Musquash generally lives in a burrow dug out of the bank of the stream in which he disports himself, and consisting of a chamber with numerous passages, all of which open under the surface of the water. But, under certain conditions, especially in the north, he builds himself a house of a rounded or dome-like form, composed of sedges, grasses, and similar materials, plastered together with mud, and supported upon a mound of mud of sufficient height to raise it above the water. The house contains a single chamber from sixteen inches to two feet in diameter, and is entered by a passage which opens at the bottom of the water. Other passages are said to issue from this, and to lead down into the ground under the bottom of the water; these are made by the animal in his search for the roots of water-lilies and other aquatic plants, which constitute a great part of his nourishment. The Musquash also seeks provisions on land, and in this way often does much mischief in gardens. Fresh-water mussels also form a part of its diet. It passes the winter in its house, which it then furnishes with a soft bed of leaves, grasses, and sedges, and, according to Audubon, ventilates by covering the middle of the dome only with a layer of similar materials, through which the air can pass. Of the propagation of the Musquash very little seems to be known with certainty. They pair in April and May, and the female produces from three to six young at a birth; but whether this takes place once or several times in the course of the summer is a matter of doubt. They are captured in fall-traps baited with apples, or by traps set at the mouth of their burrows. The Indians sometimes spear them in their houses.
MUSQUASH.
The LEMMING (Myodes lemmus) is one of the most remarkable of the Muridæ, on account of the great migrations which it performs, apparently with no special object. In Norway, where it is best known, they make their appearance in the cultivated districts in such enormous numbers, and so suddenly, that the peasants have always believed them to fall from the clouds. The Lemming is a Vole-like animal, about six inches long, of which the tail makes up about half an inch. It varies considerably in colour, but is usually brownish-yellow, with dark spots above, and with a yellow streak enclosing the eye on each side of the face; the under surface is yellowish. The ears are very short, scarcely projecting beyond the fur; the eyes are small, black, and bead-like; the soles of the feet are hairy, and the claws of the fore feet much stronger than those on the hinder extremities. The Norwegian Lemmings live and breed among the peat mosses of the mountains. They are lively and active little creatures both by day and night, and feed upon the scanty vegetation of their Alpine home—grasses, lichens, the catkins of the dwarf birch, and roots. They are active even through the winter, when they make passages for themselves under the thick covering of snow which then veils the whole country, and thus are enabled to go in search of their ordinary food. They also make their way up to the surface, upon which they may occasionally be seen running, even in the depth of winter. They breed in their burrows and under stones, and must be very prolific, seeing that every predaceous animal in the country destroys and devours them. The Lemming is, in one sense, an exceedingly timid little creature, the slightest disturbance of its quietude, or even the passing over-head of a cloud, being sufficient to alarm it; but when attacked it displays the most dauntless courage, standing on the defensive against both men and animals, and biting very sharply at anything that comes within its reach. From time to time, from some unexplained cause, the Lemmings start in vast swarms from their mountain fastnesses, and make their way in a straight line in some definite direction. Nothing seems to turn them from their course; they go straight on, over hill and dale, and, although said at other times to have an aversion to water, they now swim across any lakes or rivers that come in their way. In this operation many of them lose their lives, for they require smooth water for their navigation, and the least breeze ruffling the surface suffices to send hundreds of them to the bottom. In this way they gradually arrive at the cultivated regions, where they do so much damage to vegetation, that in olden times a special form of prayer and exorcism was in use against them. Their march is accompanied by great numbers of carnivorous beasts and birds of all sorts. Wolves, Foxes, and Wild Cats, and the smaller quadrupeds of the family Mustelidæ, Eagles, Hawks, and Owls, all prey upon them with avidity—even the Reindeer is said to stamp them to death; and the story of his eating them, long discredited, has been confirmed on good authority, while man, with his Dogs and Cats, is not behindhand in the work of destruction. Nevertheless, a great multitude survives all these dangers, and, strange to say, the termination of this painful migration is always the sea, into which the survivors of the march plunge, and, apparently, voluntarily commit suicide. Mr. Crotch, who has published several papers on the Lemming and its migrations, says that in Norway these animals always proceed from the central backbone of the country in an east or west direction, and that in either case the survivors of the march drown themselves, those that go westward in the Atlantic, those that go eastward in the Gulf of Bothnia. His notion is that the migration is in obedience to an inherited instinct acquired at a time when there was land where the sea now rolls; but there are many difficulties in the way of such a hypothesis.
LEMMING.
Besides the Scandinavian Lemming above noticed, several other species occur in the northern parts of the world. Three species (Myodes lagurus, obensis, and torquatus) inhabit Siberia; the latter two are found in North America, the last also in Greenland. In this species, which has been placed in a distinct genus under the name of Cuniculus torquatus, the third and fourth toes of the fore feet are much larger than the second and fifth (the thumb being rudimentary), and their claws become periodically enlarged to double their ordinary size by an enormous growth during winter of horny matter on the lower surface.