The forest dormouse (Dryomys nitedula) is a species of rodent in the family Gliridae found in eastern Europe, the Balkans and parts of western Central Asia. It is categorized as being of least concern in the IUCN List of Threatened Species due to its wide range and stable population trend. Forest dormice have a diploid count (2n) of 48 chromosomes. Even though this species lives in a variety of geographic locations, its greatest population density is in the forests of central Moldova, in Transcaucasia, and in the mountains of Central Asia. In most other locations, population density of this species is rather low. Population density is dependent on many factors. But the main features that this species depends on for choosing a location are the presence of the appropriate food sources as well as good foliage that can be used for a habitat. The reason why the forests in central Moldova have the highest population density is they provide the largest diversity of food sources which are available throughout the year. This location also provides the best type of foliage for the forest dormice to build their nests as well as swing from branches. The combination of both of these aspects allows for this species to have its highest needs met. Therefore, during mating season they produce offspring who also stay in the same general area when they mature. It makes sense not to move from an area if it is providing for your most basic needs.
The common name for Eliomys is the garden dormouse. Dryomys are often compared to Eliomys as they have many similarities. However, Dryomys is smaller in size. Two more differences between the two are the braincase for Dryomys is more rounded and the auditory bullae is smaller than that of Eliomys. In addition, their tails are slightly different. The Dryomys's tail is more uniform in color than that of Eliomys. The forest dormouse competes in artificial and natural nests with hazel dormice, fat dormice, and birds. Its biggest competitors are those species which eat similar types of food and who live in the same kind of habitat.
Morphology
Its appearance is squirrel-like. On average, the forest dormouse is 110 mm long with a fluffy grey tail nearly as long as its body. The head and body length can range from 80 mm to 130 mm, while the length of the tail can range from 60 mm to 113 mm. The range of its body mass is between 18 grams and 34 grams. The fur on the upper parts of the body is grayish-brown while the underparts are yellowish-white. A black stripe surrounds the eye and extends to the small ear. The whiskers form a bushy tuft about 10mm long. There are six pads on each paw. It has bilateral symmetry and is endothermic.
Distribution and habitat
The range of the forest dormouse is from Switzerland in the west, through central, eastern and southern Europe, the Balkan Peninsula, northward to the Baltic Sea and eastward to the Volga River and the Ural Mountains in Russia. Isolated populations occur outside this range, including in Israel, central Iran, Afghanistan, the Tien Shan mountains and Sinkiang in China. The forest dormouse lives in a wide range of habitats, including broad-leaved, mixed and coniferous woodlands. It is also found in rocky areas, dwarf montane woodland, evergreen shrubland and wood-steppe. It is reported to be found at altitudes up to 3,500 m.
This species is most likely to be found in dense forests. Forest dormice tend to create their natal nests on top of lower tree branches or in the midst of thick shrubbery. These nests are usually one to seven meters above ground level. They are spherically shaped with a diameter between 150mm to 250mm. Typically these nests only have one entrance and it faces the tree trunk. The outside of the nest is made from leaves and twigs. The inside of the nest has a lining that is created from bark and moss pieces. Forest dormice tend to pay great attention to detail when they create these natal nests. They want to make sure their young are protected.
Biology
Depending on where this species is geographically located determines whether or not it hibernates and for how long. In Israel, forest dormice stay active throughout the year. However, during the winter they do go through a period of torpor for a certain amount of time each day. Forest dormice located in the north tend to hibernate from October until April. During this period of hibernation, northern dormice will sit on their back legs and curl up into a ball. Its tail will wrap around its body and its hands may touch its cheeks. In all hibernating species, body temperature decreases from the range of 35-37 °C to about 5 °C.