In the copse and thick hedgerow where the Dormouse is mostly to be found, he must be sought after the brightness of day has departed; for he is a nocturnal beast and spends the hours of sunshine in heavy slumber. So deep is his somnolence, and so low his temperature, that one not accustomed to his ways might easily imagine him to be actually dead. It is not a case of "sleeping with one eye open" with the Dormouse; he needs, as it were, to be shaken to arouse him. One autumn many years ago we frequently found the empty shells of cob-nuts in our greenhouse, and were somewhat puzzled to account for their presence. A thick row of cob-bushes in our neighbour's garden ran along the back of the greenhouse, but we never suspected that they were haunted by Dormice. One day in selecting a flower-pot from a number of empty ones that lay "nested" one within another a hoard of splendid nuts was found occupying the available space in several of them. Then a common box mouse-trap was set, and next morning it contained a plump Dormouse, curled up on its back with all the appearance of death, and it was lifted out by the tail without immediately awaking. Four or five were caught in this manner on successive nights.
For diurnal privacy and comfort the Dormouse constructs a globular nest of twigs, moss and grass, about three inches in diameter (sometimes with a circular opening), which may be among the stubs in the coppice, beneath a tussock of grass, or even suspended high up in the bushes. The nursery nest is twice this size. In some districts the nest will be constructed of the bark of old honeysuckle stems, which shreds off in ribbons. The inner lining is of the same material more finely divided, with a bed of leaves. Several litters of three or four, or even six or seven, blind and naked young are born in spring or summer; but there are also records of young being found in September or October. Having regard, however, to the hibernating habit of the species it is probable that these perish, for autumn-born young would scarcely be in fit condition to go without food for a long period. In their first coat the young are more grey than red, but gradually assume the adult tint. There are no scent glands.
The adults have usually retired by the middle of October, by which date they have prepared for a long sleep by accumulating much fat beneath their coats, and make further provision by laying up a store of nuts. The reason for the latter is that the Dormouse's sleep is not continuous. It wakes up at intervals, has a good meal, and resumes its sleep. Its activities are not resumed until the spring, so that its retirement lasts nearly for half the year. Its winter nest is usually under moss among roots, or far underground. Its sleep is profound, without breathing, and it becomes absolutely cold.
The food of the Dormouse is much the same as the Squirrel's, but it is particularly fond of the hazel-nut, a good fat producer, and the "haws" of the whitethorn. It does not crack the shell of the nut, but gnaws quite a small hole, extracting the kernel piecemeal. In addition it eats many insects, and sometimes indulges in birds' eggs or even the birds themselves, if they can be captured.
The Dormouse is frequently kept as a pet for children, for which its gentle, fearless manner and non-disposition to bite seem to make it specially suitable; but we have found it regarded by youngsters as "a bit of a fraud" in this character, for as they have said, "It doesn't wake up until we are asleep." We have found that in semi-captivity it woke on most evenings throughout the winter to enjoy a supper of apples and nuts. Freshly captured specimens become tame at once. Ours were fond of climbing the long window curtains and hunting for flies—for the Dormouse is insectivorous as well as frugivorous. It is not given to the gnawing of wood, like the true Mice; and it is said to be one of the creatures that are immune to Viper poison.
The Dormouse is a European animal, but it does not extend northwards of Sweden. In agreement with this distribution, it does not occur in Scotland. From Ireland it is entirely absent. Eastward it extends only to Asia Minor.
The head is comparatively large, with blunt muzzle, prominent eyes, broadly rounded short ears, and long whiskers. The dentition is much the same as that of the Squirrel: there is a single large incisor on each side of the upper and lower jaws, and one premolar and three molars after a considerable blank: i 1/1, c 0/0, pm 1/1, m 3/3 = 20. The enamel ridges of these cheek-teeth constitute a rasping surface such as no other mammal possesses.
The soft, dense fur of the Dormouse was of repute anciently as a remedy for ear diseases and paralysis. The English name can be traced back certainly to the fifteenth century, and is considered to embody the verb dorm = to doze, still used in the North of England, which brings it very close to the Sleepmouse of Southern England and Sleeper of other parts. Derrymouse, Dorymouse, and Dozing-mouse are other local variants.
Albino varieties are very rare; but individuals with white-tipped tails are reported not infrequently.
Harvest Mouse (Micromys minutus, Pallas).