Glis glis, commonly known as the edible dormouse or fat dormouse, belongs to the order Rodentia and the family Gliridae. It is native to most of continental Europe, extending eastward into the Caucasus and western parts of Asia Minor. The species inhabits deciduous and mixed woodlands, hedgerows, and rocky outcrops where mature trees provide ample nesting sites. Adults are characterized by a robust body, large dark eyes, and a long, bushy tail that can equal the head‑body length. Their dense fur ranges from brown to reddish‑brown, offering camouflage among leaf litter. Edible dormice are hibernators, entering a deep torpor for up to six months when temperatures drop below 10 °C. They construct communal nests called “dormice” in tree cavities or under bark, which serve as both breeding and hibernation sites. Historically, the species was prized as a delicacy in Roman cuisine, giving rise to its common name. In modern ecosystems, it acts as a seed disperser and a prey item for owls, foxes, and mustelids. Seasonal fluctuations in food availability drive its intensive caching behavior, which influences forest regeneration patterns. The IUCN Red List classifies Glis glis as Least Concern due to its wide distribution and large overall population, although some peripheral populations are declining. Conservation measures focus on preserving mature forest habitats and maintaining connectivity between woodland patches.

Edible dormice are primarily nocturnal and arboreal, spending the night foraging among branches and the canopy. Outside the breeding season they are largely solitary, each individual maintaining a home range of 0.5–1.5 ha that overlaps only minimally with conspecifics. During autumn, individuals congregate in larger communal nests to share body heat, a behavior that enhances survival through the early stages of hibernation. Communication relies on a repertoire of soft squeaks, chirps, and a distinctive alarm call emitted when predators are detected. Scent marking using glandular secretions on twigs and nest material reinforces territorial boundaries. The species exhibits a high degree of flexibility in activity patterns, adjusting foraging intensity according to ambient temperature and food abundance.

Glis glis is an omnivorous forager with a strong preference for high‑energy foods that support its long hibernation period. In spring and summer, the diet consists mainly of buds, young leaves, flowers, and a variety of insects such as beetles and caterpillars. Autumn sees a shift toward abundant nuts and seeds, particularly hazelnuts, acorns, and beech mast, which are cached in shallow soil pits or crevices for winter use. Fruit consumption includes berries of hawthorn, rowan, and wild cherry. Occasionally, the dormouse will supplement its intake with small vertebrates, such as fledgling birds or amphibians, though this represents less than 5 % of total intake. Daily food consumption can reach 10–15 % of body mass during the pre‑hibernation phase, and the species employs spatial memory to retrieve stored caches, a behavior that influences seed dispersal and forest composition.

Sexual maturity in Glis glis is reached at 10–12 months for both sexes, although females often delay breeding until the following spring. The breeding season extends from March to June, with a peak in April. After a relatively short gestation of 23–30 days, females give birth to litters of 3–7 well‑developed pups, and may produce a second litter later in the summer if conditions are favorable. Nests are constructed in tree cavities, dense shrub thickets, or abandoned bird nests, where the mother provides exclusive care for the first three weeks. Neonates are altricial, opening their eyes at about 15 days and weaning by 5–6 weeks. Juveniles remain in the natal nest through the first autumn, after which they disperse to establish their own territories. Parental investment is high; females may lose up to 30 % of their body mass during lactation, reflecting the energetic demands of rearing multiple offspring.

The IUCN Red List categorizes Glis glis as Least Concern, reflecting its broad distribution and overall stable population. Nevertheless, regional threats are emerging. Habitat loss due to intensive forestry, agricultural expansion, and urban development fragments the mature woodlands essential for nesting and foraging. Road mortality is a significant source of mortality in fragmented landscapes, with studies in Germany reporting up to 12 % of local populations killed annually. In some areas, the species is considered an agricultural pest, leading to targeted control measures that can reduce local densities. Climate change poses an indirect threat by altering the timing of food availability and shortening the hibernation window, potentially increasing metabolic stress. Population surveys indicate a modest decline of 5–10 % in Central European populations over the past two decades, prompting calls for habitat connectivity initiatives and monitoring programs.

• The edible dormouse was a delicacy in ancient Rome, where it was kept in special cages called gliraria.
• It can hibernate for up to six months, reducing its metabolic rate to less than 5 % of normal.
• Individuals can store up to 1 kg of nuts in their cheek pouches and underground caches.
• Despite its name, the species is not a true mouse but belongs to the dormouse family Gliridae.
• Its large, bushy tail can be as long as its body and is used for balance when leaping between branches.