Eliomys quercinus

The black-faced dormouse or common (Eliomys quercinus) is a species of sciuromorphic rodent in the family Gliridae.. It is a small rodent that has the morphological characteristics of other dormice. It is one of the most characteristic minor species of the Spanish fauna panorama because it is present throughout the territory with a high population density, although the number of specimens has been decreasing in recent times.

Features

It is a medium-sized rodent whose length excluding the tail ranges between 10 and 17 cm. With a stocky build and a contrasting coat that has a reddish-brown color on the back and white on the underside. On its head there are two prominent ears and two characteristic black spots that extend from its large eyes to the back, resembling a mask, and which are the reason for its name. Hands with five long fingers, which allow it to easily climb trees.

It also has a long tail, whose length ranges between 9 and 13.5 cm, ending in a tuft of longer hairs, which can detach if caught by a predator and regenerate later (although there is no possibility of renewal of the tail). bone, as in lizards). It does not present sexual dimorphism, except for the breasts (four pairs) that are visible in females during the lactation stage.

The different subspecies have different weights, ranging from 50 grams in the smallest of them, to 150 g in the largest. The dormouse usually lives for about three years, although exceptionally it can reach seven.

Playback

At the end of the hibernation period, the first period of heat occurs in which courtship and copulation take place, just before summer. Pregnancy lasts approximately twenty-one to twenty-three days, with the first litter usually consisting of four or five offspring.

The second period of heat takes place from mid-July to mid-September, or after the aestivation period if the summer is very dry. This second litter usually has a greater number of offspring that can range between four and seven offspring..

The breastfeeding period lasts between twenty-five and thirty days; after these days the little ones will complete their diet outside on their own. Its growth culminates between ninety-three and one hundred and forty-six days, with the second litter interrupting its growth due to winter lethargy.

Habitat

The dormouse generally lives in wooded areas typical of the Iberian Peninsula, crags, rocky areas and even human constructions, both on the Atlantic and Mediterranean slopes, so it can be found in both coniferous and deciduous forests, meadows and holm oaks, etc. It is possible to find specimens at high altitudes above sea level, above two thousand five hundred meters.

Distribution

It is a species that is present throughout Europe, except for the British Isles and the Scandinavian Peninsula. It can be found in the Urals and North Africa.

Food and customs

It is a nocturnal species, although during the mating period it takes advantage of the last hours of the day. It is a mammal eminently adapted to eating vegetables, with tooth-shaped dentition and adequate incisors. Its diet includes cereals, nuts, and berries, but it has also developed a predatory side and includes small invertebrates such as snails in its diet. centipedes, ants, grasshoppers and arachnids. Exceptionally, it can eat bird chicks, amphibians, reptiles, eggs or even the offspring of other rodents.

At the end of summer and beginning of autumn, prior to hibernation, its diet begins to consist almost exclusively of nuts, which allow it to accumulate the necessary fats to spend the entire winter in a state of torpor. It must also be considered due to the remains of rabbits found in its stomach contents that it is capable of preying on small rabbits and hares. In captivity it has been proven that it easily captures field mice and even magpies. In the wild it can also attack this species, which is extremely vulnerable at night, as well as its eggs and chicks. These attacks can be directed, in addition to seeking sustenance, to be able to appropriate the nest that they will use in their own reproduction.

The droppings of the black-faced dormouse are located not far from its lair, presenting a great variety of nuances due to its varied diet; They are black or very dark brown in color, 0.8 to 1.5 cm long and usually pointed at one end. The feces normally present twists, and when insects have been in their diet, remains of chitin are clearly visible, since this is not digestible.

It can be found with equal ease both on the ground and in trees, where it has no difficulty in climbing to find food or shelter, using its long tail to balance itself in its runs and jumps between the trees. Its tail has also given rise to a defensive trick that the black-faced dormouse uses: when it is threatened by a predator, the dormouse diverts the predator's attention to the striking plume that adorns the end of its tail so that it tries to capture it, but by clinging At the plume, the predator will see how it detaches, allowing the dormouse to begin its escape. This is possible because the skin does not have longitudinal fibers and is not firmly linked to the muscular layer, with the hair follicles being arranged in an annular shape. In this way, the skin resembles a sheath that the dormouse has the ability to lose without causing any bleeding and occasionally enabling its regeneration.

Hibernation

This dormouse has a somewhat longer hibernation period than other similar species, which lasts from mid-autumn until well into spring. It spends that part of the year in a shelter equipped with hair or feathers as a nest, which it prepares inside a hollow trunk or in an underground shelter. During this period the dormouse can lose 50% of its body mass. In especially dry and hot summers, this species can enter a similar, although less profound torpor called aestivation.

Enemies and threats

The dormouse is the food base, along with other rodents, of foxes, wolves, various mustelids, felines and nocturnal birds of prey (in this case the study of pellets is especially useful), being also their predators, although to a lesser extent. measure, snakes and other birds such as the buzzard, or even magpies or crows that can raid their nests.

Although it is not a threatened species, a significant decline in the dormouse population is currently being observed. The causes of this fact are unknown, as it should experience a reverse trend (its direct natural enemies tend to disappear due to human action), but it is estimated that it may be related to the use of fertilizers, pesticides and insecticides that directly affect insects. on which the black-faced dormouse feeds. This may have some negative effect on fertility that causes the number of fertilizations or births of healthy offspring to be progressively reduced.

Subspecies

There are several cataloged subspecies of the black-faced dormouse, four of which are distributed in the Iberian Peninsula and adjacent islands:

• E. q. dichruruspresent in Sicily.
• E. q. gymnesicusown the Balearic Islands of Mallorca and Menorca.
• E. q. liparensisLipari, small island by Sicily.
• E. q. lusitanicuswhich is located in the southwest of the Iberian peninsula, of reddish tone.
• E. q. quercinus, present in the rest of the Iberian peninsula, has a more outdated and smaller tones.
• E. q. ophiusaewhich lives in Formentera, with the largest size of the four Spanish subspecies.
• E. q. palliduswhich is distributed by the Italian peninsula and Sicily.
• E. q. sardusown Sardinia and Corsica.

The subspecies E. q. ophiusaeis classified as rare and of special attention given the small size of its distribution area.

Despite its great phenotypic diversity in the Iberian Peninsula, its genetic variability at the mitochondrial level in this enclave is limited.