The Hazel Dormouse (Muscardinus avellanarius) is a small mammal. It is the only member of the genus Muscardinus. It is 2.36 to 3.54 in (6 to 9 cm) long with a tail of 2.24 to 2.95 in (5.7 to 7.5 cm). The Hazel Dormouse hibernates from October to April-May.
The hazel dormouse is also known as the common dormouse and is native to northern Europe and Asia Minor.
Hazel dormice are the only small mammals in Britain to have a completely furry tail. They have golden-brown fur and large black eyes. They are nocturnal creatures. They spend most of their waking hours high among the branches of trees looking for food. They will make long detours through the treetops, rather than come down to the ground and expose themselves to danger.
In winter, dormice hibernate in nests beneath the leaf litter on the forest floor. When they wake up in spring, they build woven nests of honeysuckle bark and fresh leaves in the undergrowth. If the weather is cold and wet, they save energy by going into torpor. They curl up into a ball and go to sleep. Dormice, therefore, spend a large proportion of their lives sleeping