Hazel dormouse

Appearance

The hazel dormouse can reach a body length of about 10 centimetres and a length of about 16 centimetres if you consider the tail as well. It is 6 to 9 cm long with a tail of 5.7 to 7.5 cm. It weighs 17 to 20 g, although this increases to 30 to 40 grams just before hibernation. This small mammal has reddish brown fur that can vary up to golden-brown or yellow-orange-brown becoming lighter in the lower part. Eyes are large and black. Ears are small and not very developed, while the tail is long and completely covered with hair.

Distribution

The hazel dormouse is native to northern Europe and Asia Minor. It is the only dormouse native to the British Isles, and is therefore often referred to simply as the "dormouse" in British sources, although the edible dormouse, "Glis glis", has been accidentally introduced and now has an established population in South East England. Though Ireland has no native dormouse, the hazel dormouse was discovered in County Kildare in 2010, and appears to be spreading rapidly, helped by the prevalence of hedgerows in the Irish countryside.

Status

The hazel dormouse is protected by and in UK under the Wildlife and Countryside Act.

Behavior

Starting from the onset of colder weather, the hazel dormouse will hibernate in nests on the ground, in the base of old coppiced trees or hazel stools, under piles of leaves or under log piles as these situations are not subject to extreme variations in either temperature or humidity. Dormice are almost completely arboreal in habit but much less reluctant to cross open ground than was thought even recently. When it wakes up in spring, it builds woven nests of shredded honeysuckle bark, fresh leaves and grasses in the undergrowth. If the weather is cold and wet, and food scarce, it saves energy by going into torpor; it curls up into a ball and goes to sleep. The hazel dormouse, therefore, spends a large proportion of its life sleeping − either hibernating in winter or in torpor in summer.

Examination of hazelnuts may show a neat, round hole in the shell. This indicates it has been opened by a small rodent, e.g., the dormouse, wood mouse, or bank vole. Other animals, such as squirrels or jays, will either split the shell completely in half or make a jagged hole in it.

Further examination reveals the cut surface of the hole has toothmarks which follow the direction of the shell. In addition, there will be toothmarks on the outer surface of the nut, at an angle of about 45 degrees to the cut surface. Woodmice and voles bite across the nutshell leaving clear parallel toothmarks from inside to outside. Woodmice also leave toothmarks on the outer surface of the nut but voles do not.

Food

The hazel dormouse requires a variety of arboreal foods to survive. It eats berries and nuts and other fruit with hazelnuts being the main food for fattening up before hibernation.

The dormouse also eats hornbeam and blackthorn fruit where hazel is scarce. Other food sources are the buds of young leaves, and flowers which provide nectar and pollen. The dormouse also eats insects found on food-source trees, particularly aphids and caterpillars.

Predators

* Predation from foxes, wild boars, weasels, owls and domestic cats.
⤷  Being dug up or disturbed during hibernation by badgers.
⤷  Lack of food source, e.g., from too frequent hedge-trimming, or competition from other species, e.g., squirrels, other dormouse species, mice.
⤷  Destruction of forest and hedgerow habitats, or their diverse range of species, as a broad spectrum of food is required across the calendar year.
⤷  Reduction in traditional forest management.
⤷  A warming climate.

Evolution

The oldest fossils of the genus "Muscardinus" date to the Serravallian stage of the Middle Miocene approximately 13.8 to 11.6 million years ago in what is now Spain. The oldest fossils of the modern species date to the Early Pleistocene.