Европейская лесная соня (Glis glis)

Species of rodent

The European edible dormouse or European fat dormouse (Glis glis) is a large dormouse and one of only two living species in the genus Glis, found in most of Europe and parts of western Asia. The common name comes from the Romans, who ate them as a delicacy.

The word dormouse comes from Middle English "dormous", of uncertain origin, possibly from a dialectal *dor , from Old Norse "dár" (benumbed) + Middle English "mous" (mouse). The word is sometimes conjectured to come from an Anglo Norman derivative of dormir (to sleep), with the second element mistaken for mouse, but no such Anglo Norman term is known to have existed. The Latin name "glis", which is the origin of the scientific name, is from the Proto Indo European root *gl̥h₁éys (“weasel, mouse”), related to Sanskrit गिरि (girí, “mouse”), and Ancient Greek γαλέη (galéē, “weasel”).

The European edible dormouse is the largest of all extant dormice, being around in head body length, plus an 11 to 13 cm long tail. It normally weighs from , but may almost double in weight immediately prior to hibernation. It has a generally squirrel like body, with small ears, short legs, and large feet. Its fur is grey to greyish brown in colour over most of the body, while the underparts and the inner surface of legs are white to pale buff; the line of demarcation is rather well defined. The edible dormouse is capable of limited autotomy; if another animal grasps the tail, the skin breaks easily and slides off the underlying bone, allowing the dormouse to escape. The exposed vertebrae then break off and the wound heals over, forming a fresh brush of hair. It is rather more sparsely distributed through central and southeastern Europe, but can be found as far northeast as the upper Volga River, i. e. in the Zhiguli Mountains of western Russia. It is also found in scattered populations throughout Thrace, a region in southeastern Europe along the Aegean and Black Seas. In this region, two subspecies of the edible dormouse are found, G. g. glis and G. g. orientalis. Northern Anatolia has a different subspecies, G. g. pindicus. A small, isolated population of Glis glis also exists in southeast England. At the turn of the 20th century, the British banker and zoologist Lionel Walter Rothschild kept Glis glis in his private collection in the town of Tring in Hertfordshire; in 1902 some of the animals escaped and reproduced, establishing themselves in the wild as an invasive species. Today, the British edible dormouse population is thought to be 10,000 strong, and Glis glis have been recorded in a radius of Tring, mostly concentrated to the south and east. The area of distribution has been described as a 200 square miles (518 km2) triangle between Beaconsfield, Aylesbury, and Luton, around the southeast side of the Chiltern Hills. A distinct group of dormice ranging from along the coastline of the Caspian Sea from southernmost Azerbaijan east through Iran to Turkmenistan, was formerly classified in G. glis. However, phylogenetic analysis found it to be a distinct species, the Iranian edible dormouse (Glis persicus). Significant divergence has also been noted among other populations of G. glis, probably as a consequence of the Messinian salinity crisis, and more species will probably be split in the future.

Edible dormice inhabit deciduous forests dominated by oak and beech, from sea level to the upper limits of such forests at They prefer dense forests with rocky cliffs and caves, but may be found in maquis vegetation, orchards, and urban margins. They have frequently been reported from caves as deep as , where they can shelter from predators. Females inhabit only very small home ranges, of , but males occupy much larger ranges of , with several burrows. Unlike other glirids, which are generally omnivorous, the edible dormouse has been described as purely herbivorous. Edible dormice also consume large numbers of beech tree seeds. A single, large, seeding tree within the home range of a dormouse can produce enough resources to support the energy requirements of reproduction. The location and age of a beech tree helps dictate where a population of dormice live, since older trees produce more seeds.

Edible dormice are nocturnal, spending the day in nests taken from birds, or located in hollow trees or similar shelter. They are good climbers, and spend most of their time in the trees, although they are relatively poor jumpers. The dormouse uses sticky secretions of plantar glands when they are climbing on smooth surfaces to prevent them from falling. Many edible dormice mothers form communal nesting areas where they care for their young together. They prepare a den in soft soil or hidden in a cave, and rely on fat reserves to survive through the winter. During hibernation, metabolic rate and body temperature fall dramatically, and the animal may cease breathing altogether for periods up to an hour. In years with low food availability edible dormice can hibernate longer than 11 months. In the wild most edible dormice hibernate for three winters, and then die in the fourth while hibernating, when their cheek teeth are worn out to a degree that prevents normal mastication of food. Their primary predators include owls, snakes, foxes, pine martens, weasels, and wildcats. Variation in food resources strongly influences reproduction because reproduction is tightly linked to the availability of energy rich seeds. Therefore, edible dormice breed during the phase of high food availability. Females are able to produce additional young if amino acid rich foods like inflorescences, unripe seeds, and (or) larval insects, which also increase their numbers by eating the same enriched plant food, are available. An abundance of energy rich seeds allows newborn dormice to increase their body fat to prepare for their first hibernation. Females reach sexual maturity at 351–380 days old and males significantly lower their body mass during mating season. Males are not territorial, and may visit the territories of several nearby females to mate, becoming aggressive to any other males they encounter. The male attracts a female by squeaking, then conducts a circular courtship dance before mounting her. During mating season, males lower their body mass and use their body fat reserves to help fuel the energetic costs of reproduction. The breeding habits of the edible dormouse have been cited as a possible cause of its unusual pattern of telomere lengthening with age. In humans and other animals, telomeres almost always shorten with age.

Although the edible dormouse is the only living member of its genus, a number of fossil species are also known. The genus Glis first originated in the middle Oligocene, although it did not become common until the Pliocene. By the Pleistocene, only one species, G. sackdillingensis, is known to have survived, and this is likely the ancestor of the modern species, which first appeared in the early to mid Pleistocene. Although it is not known why, the number of teats on a female edible dormouse varies across regions of Europe. For example, those in Italy have two to seven, while those in Lithuania have three to six.

[[File:Fire damaged house in Highfield Road (geograph 4659111). jpg|thumb|A house in Tring, Hertfordshire, England, damaged by a fire attributed to Glis glis in 2015 and a three day internet outage across Tring in August 2023 was attributed to the activity of Glis glis chewing through the broadband cable. Despite being regarded as a pest in the United Kingdom, In the long term, an individual trap strategy may be not sustainable if it is not integrated with other preventive tools.