Wood Mouse

The wood mouse (Apodemus sylvaticus) is a murid rodent native to Europe and northwestern Africa. It is closely related to the yellow-necked mouse (Apodemus flavicollis) but differs in that it has no band of yellow fur around the neck, has slightly smaller ears, and is usually slightly smaller overall: around 90 mm (3.54 in) in length and 23 g in weight.[2] It is found across most of Europe and is a very common and widespread species, is commensal with people and is sometimes considered a pest.[1] Other common names are long-tailed field mouse, field mouse, common field mouse, and European wood mouse.[3] This species is a known potential carrier of the Dobrava sequence of hantavirus which affects humans and may pose serious risks to human health.[4]

wood mouse

Wood mice inhabit forests, grasslands, and cultivated fields, tending to seek out more wooded areas in winter.[5] Almost entirely nocturnal and terrestrial, wood mice burrow extensively, build nests of plants and live in buildings during harsh seasons. It is one of the most intensively studied species in the genus. In Europe, it ranges north to Scandinavia and east to Ukraine. The wood mouse is also found in northwestern Africa and on many Mediterranean islands.[6]

Wood mice are mainly active during the dark, probably having evolved so to avoid predation, employing several anti-predatory strategies, though breeding females may be more active in daylight in order to collect sufficient food.[10] While foraging, wood mice pick up and distribute visually conspicuous objects, such as leaves and twigs, which they then use as landmarks during exploration.[11][12] If a wood mouse is caught by its tail, it can quickly shed the end of it, which may never regrow.[13] Despite its name, it prefers hedgerows to woodland. During the colder months, wood mice do not hibernate; however, during severe winter seasons they can fall into a torpid state, a decrease in physiological activity.

The wood mouse has a breeding season from February to October in which multiple matings occur between males and females, resulting in scramble competition. Such behavioral characteristics result in sperm competition and multiple paternity litters. The society is polygynous with copulation resulting from scramble competition during reproductive periods. Males possess a sac known as the cauda epididymis, which stores sperm and lies underneath the scrotal protrusion. Temperature regulation ensures maximum sperm output.

Wood mice eat nuts, seeds, insects and green plant material. In mixed deciduous woodland they like acorns, ash and sycamore seeds in the winter, buds in the spring, caterpillars, worms and centipedes in early summer and blackberries and fungi in autumn.

The wood mouse is most often confused with the yellow-necked mouse. Both have dark brown fur on top with white underneath with prominent eyes and ears. The best way to tell them apart is by the amount of yellow-coloured fur near the throat.

The yellow-necked mouse, as the name suggests, will have a yellow collar that reaches all the way from the brown on one shoulder to the brown on the other. Although the wood mouse might have a yellow patch, it will not reach all the way around as seen in the yellow-necked mouse.

A female wood mouse will give birth to litters of 4-7 young in successive pregnancies from around March to October however Autumn litters are often smaller. Young are weaned at between 18 and 22 days old when they weigh 6-8 grams. One litter can contain mice of different fathers and only the female looks after them.

Despite being one of our most common woodland mammals, the small, sweet and secretive wood mouse is hard to spot. They feast on nuts, seeds and invertebrates and are an important food source for larger mammals and birds of prey.

Wood mice are primarily nocturnal and prefer to stick to dense cover, making them hard to see. For the best chance of seeing a wood mouse, be as quiet as possible and watch sources of possible food, such as fruit and nuts.

Studies of woodland seed crops and population numbers organised by the Mammal Society show that the seed crop size strongly influences wood mouse numbers in the same autumn and in the following summer (more food leads to higher numbers and better survival). Numbers are probably synchronised: highs and lows tend to coincide in different parts of Britain, possible because tree seed crops are synchronised.

Sandy brown fur with white/grey underside and a long tail. Protruding eyes and large ears. Tail dark and hairy. Does not have yellow V-shaped collar across the neck which distinguishes the yellow-necked mouse, however, may have a smaller neck tie of yellow that does not reach all the way around. Head and body length 8-11cm, tail length 7-11cm.

House mouse (Mus domesticus)Grey/brown fur all over, usually no contrast between top and underside, as opposed to wood mouse which has a clear contrast of red/brown fur on top and a paler (often white) underside. Smaller size than wood mouse and proportionately smaller ears (about half the size). House mouse has stronger smell and can leave greasy marks from its fur.

Yellow-necked mouse (Apodemus flavicollis)Slightly larger than the wood mouse, with proportionately slightly larger eyes and ears. Paler grey underside than wood mouse. Usually more lively and loud than wood mouse when caught. If you get a closer look: unbroken yellow band around neck, joining forelegs, whereas in wood mouse there is just a longitudinal yellow/orange streak down the chest (this is the distinguishing feature between the two species, do not attempt to identify these two species without a close up view of this, they are usually too similar to tell apart without seeing this).

Hazel dormouse (Muscardinus avellanarius)Orange/yellow coat on top with yellow underside and white on throat, much paler than the wood mouse which has a red/brown coat on top with contrasting pale (often white) underside. Hazel dormouse has larger black eyes but wood mouse has larger, more prominent ears. Dormouse has a very furry tail which wood mouse does not have.

VolesVoles are different to mice in that they have a more rounded muzzle, whilst the muzzle of a mouse is pointed. Voles have smaller eyes and smaller, more subtle ears that are often covered by fur. Mice eyes and ears are large. Voles often have shorter tails. There are exceptions of course: water voles have long tails and it is often said that harvest mice have vole-like proportions as they have a more rounded muzzle and subtle ears and eyes.

Spermatozoa from a single male will compete for fertilization of ova with spermatozoa from another male when present in the female reproductive tract at the same time. Close genetic relatedness predisposes individuals towards altruism, and as haploid germ cells of an ejaculate will have genotypic similarity of 50%, it is predicted that spermatozoa may display cooperation and altruism to gain an advantage when inter-male sperm competition is intense. We report here the probable altruistic behaviour of spermatozoa in an eutherian mammal. Spermatozoa of the common wood mouse, Apodemus sylvaticus, displayed a unique morphological transformation resulting in cooperation in distinctive aggregations or 'trains' of hundreds or thousands of cells, which significantly increased sperm progressive motility. Eventual dispersal of sperm trains was associated with most of the spermatozoa undergoing a premature acrosome reaction. Cells undergoing an acrosome reaction in aggregations remote from the egg are altruistic in that they help sperm transport to the egg but compromise their own fertilizing ability.

Hantaviruses are rodent-borne, emerging viruses that cause life-threatening human diseases in Eurasia and the Americas. We detected hantavirus genome sequences in an African wood mouse (Hylomyscus simus) captured in Sangassou, Guinea. Sequence and phylogenetic analyses of the genetic material demonstrate a novel hantavirus species, which we propose to name "Sangassou virus."

The Wood mouse is quite similar to the yellow-necked mouse, although differs from latter by absence of yellow collar, resembling a bib on the animal's chest. The Wood mouse is otherwise known as 'the Long-tailed field mouse' due to its long tail that is approximately the same size as the total length of the head and body. It's the most widespread and abundant rodent, native to the British Isles. The overall coloration of its fur is reddish-brown. The belly of the animal is either white or greyish.

The Wood mouse has a rather large area of distribution, stretching from Britain and nearby islands to continental Europe (except for northern Scandinavia and Finland) through northwestern Africa and southwestern Asia to the Altai and Himalayan mountains. This rodent is capable of living in any environment with suitable sheltering sites, but will generally prefer grassy fields, cultivated areas, woodlands and forests.

Wood mice have a polygynous mating system. They breed between February and October. During this period, individuals compete for their mating rights. Female wood mice are able to produce up to 4 litters per year. Gestation period lasts 21 - 26 days, yielding 4 - 7 young, which are born in a nest chamber in their mother's burrow that is lined with soft underlay of leaves, moss and grass. The eyes of newborn babies are closed, opening at 6 days old, by which time they have attained their fur, which is darker than that of mature individuals. At 3 weeks old, young are driven out of the nest by their mother, after which they begin living independently. Within two months, young Wood mice become reproductively mature.

Although classified as Least Concern, Wood mice suffer from hedgerows and loss of their woodland habitat. They are also potentially threatened from agricultural modifications in a form of chemicals, which can be a serious concern both directly and through food contamination. 041b061a72