Habits: The nocturnal dormouse is the smallest of all the dormouse species. It spends all of its life in trees and shrubs. It has excellent hearing coupled with the large round eyes of many nocturnal animals. The dormouse sleeps during the day in a round nest that it weaves from grasses and bark. This snug sleeping nest is about three feet off the ground or at the top of a mature tree, sometimes over 65 feet high. At night the dormouse looks for food in the treetops. Its padded feet and mobile wrist and ankle joints enable it to grip the branches as it runs.

Food and Feeding: The dormouse gathers all its food in treetops and bushes. It eats mainly tree flowers, berries, and nuts. In spring it eats tree flowers such as the hawthorn and picks honeysuckle berries and flowers when they are available. Sometimes the common dormouse is called the hazel dormouse because of its liking hazelnuts. It also eats acorns and chestnuts.

Breeding: The start and length of the dormouse’s breeding season depends upon the weather. After a pair mates, the female makes a nest above the ground. It is larger than the sleeping nest. The mother gives birth to her young about 24 days later. She usually has four or five babies. Born blind and naked, they grow their first fur about a week later. This coat is molted (shed) at two weeks and replaced by a gray version of the adult coat. At about 10 days their eyes open. The young stay with their mother for two months and are ready to breed the next spring. The mother may have a second litter in mild years.

Hibernation: The dormouse sleeps through winter in a nest on or underground. This period lasts from October to April. If it warms up outside the dormouse will wake briefly to feed. Before hibernating, the dormouse doubles its weight. This seasonal overeating is essential to the dormouse’s survival throughout the winter. The dormouse sleeps rolled up in a ball. Its breathing and heart rate slow down and its body temperature falls. It lives on built up body fat. If the dormouse wakes up during the winter months it may burn its fat reserves too soon and starve. While the dormouse hibernates, its body cools down to about 41 degrees.

Naturewatch: The dormouse’s sleeping habits make this creature difficult to spot during the day. Look for its nest in the canopies of young hazelnut trees, brambles, and honeysuckle vines in deciduous woodlands (where trees lose their leaves every fall). Like many rodents, the dormouse drops empty nutshells after eating their contents. It leaves a smooth, round hole in the shell, unlike the rough edges left by mice or voles. You can encourage a dormouse population to stay in your area by putting a birdhouse about 10 feet above ground level in a tree. If you do spot a nest, do not disturb it.

Key Facts:
Sizes:
Length: Head and body 2-3 in. Tail 2-2 ½ in.
Weight: ¾ oz. (up to 1 oz. Before hibernation)

Breeding:
Sexual maturity: 1 year
Mating: May to August. Usually 1 litter per year
Gestation: 21 days
Litter size: 2-7, average 4

Lifestyle:
Habit: Pairs often nest together in summer; hibernate separately
Call: Ultrasonic squeaks
Color: Rich orange-brown. Pale underside. White on throat
Diet: Tree flowers and fruits; some insects
Lifespan: About 4 years

Related Species: The largest species is the fat dormouse, Glis glis, from Europe.

Distribution: Found throughout most of Europe from Sweden to northern Spain and eastward to the Middle East.

Conservation: The decline of the dormouse in Europe coincides with the loss of ancient forests, woodlands, and hedgerows throughout its range.

The Common Dormouse and Its Nest:
Breeding nest: About six inches across, woven by the female in a tree hollow.
Nest site: Usually about three feet off the ground; sometimes over 65 feet up in a tree.
Winter nest: On or underground; enclosed.
Paws: Padded to enable the dormouse to grip branches.

Did You Know: 
During hibernation a dormouse sleeps so soundly that it can be rolled along the ground without waking.
The dormouse’s ability to sleep very deeply was made famous in the Mad Hatter’s tea party, a story from Lewis Carroll’s book Alice’s Adventures in Wonderland.
During the nineteenth century the dormouse was kept by children as a pet.
In different parts of Europe the dormouse is also called the sleepmouse, the derrymouse, or the dozing mouse.

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