Part 8

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).

With the exception of the Lesser Shrew the pretty little Harvest Mouse is the smallest of British mammals. It long held that distinction, until the Lesser Shrew was shown to be a distinct species and not the young of the Common Shrew. The Harvest Mouse will always be associated with the name of Gilbert White, for it was in his letters to Pennant that it was first made known as a British mouse, and its appearance and habits were published by Pennant in his "British Zoology."

The head and body combined measure less than two and a half inches, and the nearly naked, scaly tail is almost as long. The thick, soft fur of the upper side is yellowish-red in colour, and of the under parts white; the two colours being rather sharply separated. The tail is exceedingly pliant and prehensile, and serves as an additional foot, being at once coiled around any suitable object within reach. It has bright black eyes, short blunt nose, and short rounded ears, the latter about one-third the length of the head.

It is found chiefly in the South of England, becoming less abundant as we go north. In Scotland it is very scarce, and it does not occur in Ireland. It is more generally distributed on the Continent, where it ranges from Northern Italy to Russia and Siberia. The usual habitats of the Harvest Mouse are pastures and cornfields, where it climbs the stems of the tall grasses and corn plants, cutting off the ripe ears and carrying them to the ground where it picks out the grain. During the summer it feeds largely upon insects, caught in the same situations. At the same season it stores up much grain in burrows for use in the winter between its periods of sleep. Sometimes, however, instead of wintering in burrows in the earth, it tunnels into hayricks, and if undisturbed may even bring up a litter or two in the rick; as a rule it constructs the wonderful nursery which has won human admiration ever since White made the species known.

This is a ball-shaped nest about three inches in diameter formed of neatly plaited and woven blades of wheat or grass, with no definite opening, the grass blades being merely pushed aside to make entrance or exits where required, and closing again by their own elasticity. There is just sufficient room inside for the mother-mouse and her blind and naked offspring, whether they number four, eight, or even nine. This nest is suspended at some little distance--about half a foot--above the ground, several stems being incorporated in its walls to give it stability, or it may be lodged between the stem and leaf of a thistle, or a knapweed, in blackthorn bushes or broom. The bed is made of split leaves of corn or grass. The nests are not always so tough as that described by White, which "was so compact and well-filled that it would roll across the table without being discomposed, though it contained eight young." Several litters are produced throughout the year, varying in the number of young from five to nine; and one might expect that the species would be represented by individuals as numerous as those of the House Mouse. It must be remembered, however, that the diurnal habits of the Harvest Mouse and its methods of feeding expose it to the attacks of the larger birds; whilst the smaller carnivorous beasts do not neglect it. When the corn is cut the Harvest Mouse is often carried in the sheaves to the barn; in that case it spends the winter there, and does not go to sleep. It is considered that the modern reaping machine has caused a great reduction in its numbers.

Until about December the young of the year resemble the House Mouse in colour, and may easily be mistaken for it; then from the hind quarters forwards they begin to assume the redder tint. As the adult Harvest Mouse weighs only about a sixth of an ounce, it is not surprising that it should be able to sit on an ear of corn to which its capable little hands and prehensile tail have enabled it to climb with ease. But the familiar name must not delude us into supposing that it is only found in or about cornfields. It is also a denizen of the tall, rank herbage along ditches and untrimmed hedgerows. In winter it is frequently found about the lower parts of wheat and oat stacks.

Where the Harvest Mouse occurs it may be watched at close range by the quiet observer. Though as a rule timid and gentle in demeanour, it becomes at times savage and cannibalistic. It lacks the offensive odour of the House Mouse. Its voice is of a low chirping character, and has been likened to that of the wren.

With a more intimate knowledge of the structure of the various species of Mice, it has been found necessary to break up the old Linnean genus _Mus_ into several smaller genera. In this process our little Harvest Mouse becomes the sole British representative of the genus _Micromys_.

*Wood Mouse* (_Apodemus sylvaticus_, Linn.).

An alternative name for the Wood Mouse is Long-tailed Field Mouse, and but for the fact that Linnæus dubbed it _Mus sylvaticus_, it would be better to adopt Pennant's designation, for it is much more an inhabitant of the field, the hedgerow, and the garden than of the wood. It is, indeed, the cause of something approaching despair to the keeper of the kitchen garden; for this is the miscreant that ploughs up and eats the newly sown peas that have not been rolled in red lead or soaked in paraffin. He has also a great fondness for strawberries at the moment they have become ripe.

The Wood Mouse is about three and a half inches long from the long snout to the base of the tail; and the tail by itself falls only a very little short of that length. The fur on the upper parts is a dark yellow-brown; the under parts white. In adults the line of demarcation is always distinct. There is a spot of buff or orange on the chest whose development in certain local races has enabled recent systematists to make five species out of this one. It has large and prominent dark eyes--for it is chiefly of nocturnal habits--and its long oval ears have the inner margin turned inwards at the base. The tail is dark brown above, and whitish below. It is the commonest of the British mammals in country places, but less frequent in Ireland. It is common in Europe as far north as Sweden and Norway.

As a rule it constructs its burrows underground or under the roots of trees, and here it stores up great quantities of nuts, haws, grain, and smaller seeds for use in winter, when it becomes inactive, though it does not really hibernate. But if there is a house handy to which it can gain entrance in late autumn, it prefers to become the guest of those whose garden has been a boon to it through the spring and summer. We have had them spend the winter cosily in our rolled-up tennis nets, stowed away in a shed to keep them dry in the off-season; and as potatoes were stored in the same place they consumed a number of these. On several other occasions Wood Mice were detected attempting impudently to enter the dwelling house by the back door. Once an entire family--mater, pater, and five active youngsters--succeeded in this enterprise; but they left incriminating evidence of their presence, though they were suspected of being ordinary House Mice. Accordingly a break-back trap, baited with cheese, was set one evening, and within half an hour its loud clap proclaimed its effectiveness. This trap appeared to show that the Wood Mouse is a simple-minded, unsuspecting creature, for it was reset with the same uneaten bit of cheese-rind for bait again and again, and no sooner was the trapper's back turned than another member of the family was secured. Seven times it sprang, and then its inaction appeared to be due to the fact that there were no more possible victims, for we saw no further traces of the mice. Its general resemblance to the House Mouse frequently leads to its being mistaken for that species.

There are several litters of young during the year, and these vary in number from five to nine--an alarming rate of increase; but, fortunately, the Barn Owl that hunts the hedgerow inch by inch, every evening, takes a heavy toll that keeps the numbers down. The Fox, the Weasel, the Hedgehog, and the Viper also do their part.

The Wood Mouse is a very active creature, running and jumping in zigzag fashion, climbing high in the bushes in order to obtain berries, leaping from considerable heights, and swimming well when occasion requires. Although an accomplished excavator, it often makes use of unmortared stone walls for its runs and stores. It wanders widely in its search for berries, bulbs, and grain. In the matter of berries, it is not the juicy pulp that it desires but the seeds, which it will carefully pick out. It prefers the larger grains from the cornfield to those of a grass-meadow. It is both timid and gentle in disposition, and on account of its short sight, it may be approached closely and caught with the hand.

Its stores of food are often communal, a colony of mice contributing, for it is not always of solitary habit. These stores are of the most varied character. Of the very miscellaneous items on its menu a few may be mentioned: leaves of clover and dandelion, with flower-buds of the latter, nuts of all kinds, apples, grapes, gooseberries, crocus and hyacinth bulbs (Millais says the Dutch were taught to multiply hyacinths by division of the bulbs through observing the effects of this mouse's attacks), acorns, rose and bramble seeds, slow-worms, eggs and--putty! It has been known to enter beehives, and not only to eat the honeycomb, but impudently to construct its nest there. Deserted birds' nests are often adapted to its use, either as a dining-room when seeking haws in the hedges, or as a permanent habitation, in this case roofed with moss.

The breeding nest is a globular structure of dry grass, and is usually built in a separate chamber of the underground run, but occasionally is on the surface or under a heap of hedge _débris_. Some of the burrows may extend as much as three feet underground.

* * * * *

Towards the end of last century, Mr. de Winton called attention to what was considered to be a new British mouse--the Yellow-necked Mouse (_Apodemus flavicollis_), distinguished from the Wood Mouse by its larger size, the head and body measuring four and a quarter inches, and the brown spot on the chest commonly found in the Wood Mouse developed into an orange cross whose arms are connected with the upper side coloration--described as golden brown. This is a feature that at once attracts attention where this form occurs; but there is another distinction out of sight--there being three additional bony joints in the tail, that is thirty instead of the twenty-seven in the tail of an ordinary Wood Mouse. Whether it is a really distinct species or the typical form of the Wood Mouse is at present open to question. It is found chiefly in the southern and eastern portions of England, but its distribution also includes Northamptonshire, Herefordshire, and Northumberland.

Other local races have been distinguished also as distinct species or sub-species under the name of Hebridean Field Mouse (_A. hebridensis_) with the white of the under parts tinted with buff; Fair Isle Field Mouse (_A. fridariensis_), like the Yellow-necked but without the collar; St. Kilda Field Mouse (_A. hirtensis_) with brown under parts; and Bute Field Mouse (_A. butei_), darker, with shorter tail and ears.

*House Mouse* (_Mus musculus_, Linn.).

The most familiar, the most widely distributed and most numerous of the mammals of our country, the Common or House Mouse, stands in little need of nice description. Although of a timid and retiring nature, it can on occasion exhibit not only bold familiarity, but actual friendliness to mankind to which it has been attached for ages, preferring to live in palace or hovel with human beings to the open-air life of woods and fields. Not that he is not to be found in the open air; but then it is mostly in the immediate neighbourhood of a house, where he can make his runs in ricks of corn--mountains of food. It is this easy method of despoiling man of his goods that caused the Mouse in ancient days to attach himself to the huge creature that is so impotent in ridding himself of small adversaries. The domestic Mouse is considered to have had its home, its place of origin, in Asia, whence it has spread to every part of the world where man has gone. In most cases, it may be presumed with safety, it has travelled cosily stowed away in his stores and merchandise, so that as soon as the human migrant has built himself a home he finds that the Mouse is in occupation, and demanding a share of his food. In spite of all his serious depredations, our literature teems with evidence that the victim has always retained some kindly feeling for his pretty four-footed oppressor.

For the sake of uniformity, let us say that the head and body of the House Mouse measure a little more than three and up to four inches, and the tapering, flexible, and sparsely haired, scale-ringed tail may slightly exceed that measurement. It has a pointed snout, the bright, bead-like eyes are black, the large, sensitive brownish ears are nearly half the length of the head, and the soft, brownish-grey fur is only a little paler on the under parts. Outdoor specimens are often more yellow-brown in coloration. As compared with the Wood Mouse we have this more dusky and uniform coloration, shorter whiskers, smaller eyes, stouter and less flexible tail, and shorter legs. The thumb of the hand is reduced to a mere tubercle.

It is very active and silent in its movements, emerging from a tiny hole in floor-board or skirting and gliding without sound over the floor, ascending with ease table-legs or walls, and then, if alarmed, springing with a prodigious leap back to its hole. Concrete floors will not suffice to keep it out of a house, for it will climb the outer walls and enter the upper windows, thence making itself secret ways to the lower floors behind woodwork or plastered walls, till it reaches the kitchen, the larder or the storeroom. Though it shows by its preferences that its natural rôle is that of grain thief, it will eat any kind of human food and much besides: in a word, it is omnivorous.

Its great success as a species is due to this adaptability and to its astonishing fecundity. It produces four or five litters during the year, each consisting of five or six, or even up to twelve, blind and naked young which develop so rapidly that in a fortnight they are capable of independence. At the age of six weeks they may begin to breed.

The House Mouse exhibits a considerable range of variation in colour, both darker and lighter than the type, and many of these variations have been bred from and their peculiarities perpetuated and accentuated in confinement as "fancy" mice. Of these the most familiar are the White Mice, really albinos with pure white fur, pink eyes, feet, and tail. There are also dark, nearly black variations, and spotted examples. Sometimes one is surprised at night to find that the house is tenanted by a musical mouse that runs up the scale in what appears to be an attempt at a little song. It has been ascertained, however, that these so-called singing mice are afflicted with a form of asthma, and the supposed vocal efforts are merely the manifestation of their physical trouble. We have had experience of musical mice in another way. For several nights in succession weird sounds came from the pianoforte which suggested that fairies were using it as a harp, twanging the wires instead of striking them with the hammers. An examination of the interior seemed to indicate the actual performer, for a little pile of Spanish nuts, stolen from the table, was discovered inside; and the twanging of the notes was caused probably by the mouse climbing them. A trap baited with a shelled nut put a stop to these performances. Bateson mentions several cases of hairless Mice, except for a few whiskers.

A local race of the House Mouse found in St. Kilda is sometimes dignified with species rank under the name of _Mus muralis_. Its distinguishing features include less slender feet and tail, and slight peculiarities of the palate.

*Black Rat* (_Epimys rattus_, Linn.).

Not many years ago a good deal of modified regret was expressed because it was thought that the Black Rat--the real old British Rat as it was called--was being exterminated by that vulgar upstart the Brown Rat--the Hanoverian or Norway Rat. These laments were mainly called forth by its comparative scarcity in old London warehouses where it had formerly been very numerous. One would have thought it a matter for rejoicing that there was a possibility of our having only one species of the rat pest to contend with instead of two. The disappearance of the Black Rat was remarked by Pennant as far back as 1778. However, later observations tend to show that the Black Rat is far from being extinguished even in the City of London, where the old type of warehouse is being rapidly replaced by ferro-concrete erections with carefully trapped drains. The intelligence of the Rat is equal to little impediments of that sort, and if it cannot get in by way of the basement it can climb walls and enter by the attic windows.

On the score of sentiment we need not distinguish between the Black Rat and the Brown. They are both Asiatic aliens, though the Black Rat had been settled here for several centuries before the Brown Rat followed in his tracks. Nothing definite is known as to the date of his arrival. Geologists assure us that he was not among the indigenes, for even the most recent strata yield no remains of his bones or teeth. He is known to have been on the other side of the dividing Channel in the thirteenth century, and to have reached England soon after, and quickly to have become a nuisance. He had a clear run of over four hundred years in which to occupy the most remote portions of the island, before he had to meet with keen competition in the form of the Brown Rat. He reached Ireland in the twelfth century, if not earlier.

The Black Rat is of more slender proportions than the better known Brown Rat, and much smaller, the dimensions of the head and body being about seven inches, whilst the scaly-ringed and almost hairless tail is more than eight inches. The long, pointed snout projects far beyond the short lower jaw; the whiskers are long and black. Though presenting the appearance denoted by its popular name, the glossy blue-black fur has a good sprinkling of grey on the upper surface, whilst below it is dark grey. The large, thin ears are naked, and about half the length of the head. The feet are pink, with scale-like rings on the underside of the digits and five pads on the sole. The thumb of the forefeet is reduced to a mere tubercle.

Although the Rats have much to do with garbage and offensive matters, they take the greatest of care to maintain their own cleanliness and a spruce appearance, spending much of their time in cleaning their fur and paws. One of the reasons for regretting the possible extirpation of the Black Rat by his more pushful relative, was, no doubt, his less ferocious ways and well-known milder disposition--a trait which is obvious to any one who has handled the domesticated albino, or White Rat, which is generally considered to be of this species.

Where--as in India--the Black Rat lives a more out-of-door life, it climbs trees and mostly makes its nest in them. With us the doe collects a good quantity of suitable materials--rags, paper, straw, etc.--and constructs a roomy nest which she uses for successive broods, which come at short intervals. Seven or eight is the usual number for a litter, and there are five or six broods in a year.

In the matter of food, both the Rats are omnivorous, and it is, therefore, useless to attempt to give a list of substances acceptable to them. Fish, flesh, fowl, or vegetable, crustacean or mollusc--anything that can be digested--is eaten by them; and if all else fails they will eat their own kin. In this matter the Brown Rat, from his superior size and ferocity, has the advantage, as is emphasised by an incident told by a professional rat-catcher to Frank Buckland. He said that having had a successful haul in infested premises he had turned all his captures both Black and Brown into a large wire cage, intending to have a little sport next day with a few cronies and a terrier or two. To his astonishment next morning all the Black Rats had disappeared and only the Brown--or some of them--remained.

A sub-species, the Alexandrine Rat (_Epimys rattus alexandrinus_), with brown back and dusky underside, is frequently introduced with shipping from North Africa, and has been recorded from Lundy Island and Shetland. Another sub-species, the Tree or Roof Rat (_E. rattus frugivorus_), common in the Mediterranean region, often appears in our ports. It has long, soft and dense fur, of light grey or brown on the upper parts and whitish below (pure white to pale yellow), and the feet usually white above.