# Natural History: Mammalia/Muridæ

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Family II. Muridæ.
(Mice.)
The very extensive group of small rodent animals which have received the name of Rats and Mice, have in each jaw, besides the two incisors common to the Order, three molars on each side, fixed by distinct roots, the crowns of which are surmounted by blunt tubercles, which when worn down assume the form of a disk variously indented. The teeth of the upper jaw shelve backwards, those of the lower forwards. The tail is long, round, and tapering to a point; furnished with short hairs or scattered bristles, growing at intervals from beneath scaly rings formed by the outer layer of the skin (epidermis). There are always five toes on the hind feet, and usually four on the anterior, with the slight rudiment of a thumb: the feet are neither webbed nor fringed with stiff hair; though several species swim with facility. The fur is often intermixed with longer bristles, or flat spines.
The ordinary food of the animals before us consists of grain, seeds, and farinaceous vegetable substances; and for the bruising of these the structure of their teeth is adapted. Yet we might infer from it that animal food would not be rejected by them: and experience abundantly proves this to be the case. The depredations of our most ​common species upon the contents of our larders and pantries are but too extensively known; and the carnivorous voracity of the Brown Rat is shown in a very striking and even revolting manner in the horse slaughter-houses at Paris, where the carcases of the horses killed in the course of a day, sometimes amounting to thirty-five, are during the night picked to the bare bones by these creatures. They also attack with ferocity and devour any small animals they can master; and have sanguine encounters among themselves.
The fertility of the Mice is very great; so that, notwithstanding the incessant warfare waged on them by man in various ways, they baffle all his efforts to extirpate them. They have been carried, in their intrusive and unwelcome state of semi-domestication, wherever civilized man has established his domain; so that it is now difficult to ascertain the original residence of these our most common vermin. Other species, however, are very numerous, and are found over the whole globe: especially in South America.
Genus Mus. (Linn.)
In this, the typical genus of the Family above described, we find the incisors of the usual number, the upper ones wedge-shaped, the lower compressed and pointed; three molars on each side, both above and below; the fore one the largest, the hind one the smallest. The muzzle is pointed, and more or less lengthened; the ears oblong or rounded, frequently very large, and almost naked. The limbs are short, and of the ​usual relative proportions; the tail scaly, long, and gradually tapering.
We illustrate the genus by the pretty little Harvest Mouse (Mus messorius, Shaw.), the smallest, as we believe, of all quadrupeds; certainly of such as inhabit this country. The length of its head and body does not exceed two inches and a half, and that of the tail is not quite so much.
HARVEST MOUSE.
Its colour is a bright reddish brown above; the under parts are pure white. White, of Selbourne, first made it known as a British species, and describes its beautiful globular nest, as "most artificially platted, and composed of the blades of wheat; perfectly round, and about the size of a cricket-ball, with the aperture so ingeniously closed that there was no discovering to what part it belonged. It was so compact and well-filled ​that it would roll across the table without being discomposed, though it contained eight little Mice that were naked and blind . . . This wonderful procreant cradle, an elegant instance of the efforts of instinct, was found in a wheat-field suspended in the head of a thistle."
NEST OF HARVEST MOUSE.
The principal food of the Harvest Mouse is corn; but it is fond of insects also, as was accidentally discovered by Bingley, in one which he had in captivity. "One evening," he observes, "as I was sitting at my writing-desk, and the ​animal was playing about in the open part of its cage, a large blue fly happened to buzz against the wires. The little creature, although at twice or thrice the distance of her own length from it, sprang along the wires with the greatest agility, and would certainly have seized it, had the space between the wires been sufficiently wide to have admitted her teeth or paws to reach it. I was surprised at this occurrence, as I had been led to believe that the Harvest Mouse was merely a granivorous animal. I caught the fly, and made it buzz in my fingers against the wires. The Mouse, though usually shy and timid, immediately came out of her hiding-place, and running to the spot, seized and devoured it. From this time, I fed her with insects, whenever I could get them; and she always preferred them to every other kind of food that I offered her."