The fat dormouse is nocturnal, and lives in groups with related individuals (4). Adapted for climbing and leaping through the tree canopy (3), this species feeds on nuts, fruit, bark and fungi as well as animal matter including insects, bird eggs and even small birds (4). The breeding season occurs between June and August, during this time, fighting between males may occur over access to females (3). Females attract males to mate with them by rubbing their anal area along the ground. This produces an odour trail, which the male sniffs and scent-marks (5). Whistling sounds also indicate readiness to mate. The male will pursue the female for a while; she may rebuff him aggressively, but when he gives up she often follows him, and mating occurs (5). Males usually leave the female after mating takes place in order to find more potential mates (5). Females produce one litter a year, consisting of 2-9 young (4), typically in a nest inside a hollow tree (3), lined with grass, feathers and hairs (5). The young are born blind, naked and helpless, and are weaned by about 4 weeks of age (3). Mother and offspring seem to learn to recognise each other by exchanging saliva (7). The fat dormouse hibernates underground or in grass-lined hollows in trees from October to April (4). Towards the end of summer they begin to construct tunnels in the ground; they enter these tunnels to hibernate as soon as the weather begins to get cold, and groups of fat dormice have been found hibernating together (5).