Myoxus glis Linnaeus - Fat Dormouse, Edible Dormouse


Glis glis L.

Systematic position.

Class Mammalia, order Rodentia, family Myoxidae, genus Myoxus. There is only 1 species (2 n = 62) in the territory of the former USSR with 3-4 subspecies of 9 known for the genus as a whole.

Biological group.

Pest of fruit crops.

Morphology and biology.

This species is the largest representative of the dormice family. The body length amounts to 130-180 mm; tail 110-154 mm; ear 16-26 mm; back foot 23-30 mm; weight varies in the limits of 70-189 g. Auricles are rather short, with rounded tips and covered with thick hairs. Vibrissae of moustaches are grouped in bunches with a length reaching 60 mm. The bunches and moustaches move independently of each other. The fur is magnificent; tail is covered with rather long hairs lying along both sides of the tail. The coloring of back is smoky-gray or grayish-brown, lower part of body is white or light gray; belly and breast are white. There is usually a dark ring around each eye. Sexual dimorphism is not expressed in either the size or the coloring. The subspecies differ a little in size, the length of tail, and the coloring of fur. The sex ratio in a population changes by years; number of males is usually larger than that of females. Sexual cycle in females occurs once for the active period with only one litter; 50-60% of adult females usually participate in reproduction. Pregnancy lasts 25 days; amount of young dormice varies from 1 to 10, averaging 5 or 6. They begin to see clearly in 18-21 days and at 25 days the try to start independent feeding; young, fat dormice leave their nest in one and a half months and the migration period begins. First time animals of a litter move jointly, sometimes traveling together for wintering. Sexual maturity of fat dormice comes the next year and reproduction begins only in the second or even third year of life. The age limit for this dormice species is 4.5 years. Males mark the borders of individual plots, participating in training young animals. Families winter by groups in the same nest.


The Fat Dormouse inhabits southern, central and eastern Europe including Sicily and Crete islands in the Mediterranean Sea, also Iran and Turkmenistan. In the territory of the former USSR this species is distributed rather sporadically in the middle strip of the European part of Russia, in the Caucasus, southern and western Transcaucasia, Carpathians, Transcarpathian territory.


It occupies deciduous and mixed forests, orchards. Fat dormice use hollows of old trees, frost cracks or trunks splintered by lightning for their nests. Examples of co-habitating with bats are known. They eat nuts, berries, seeds, fruits, and insects in summertime. Competition for refuges and forages may occur with some animals occupying the same biotopes, for example, with the Hazel Dormouse (Muscardinus avellanarius L.). The Fat Dormouse low reproductive potential does not provide a significant increase of population density. As a consequence, sharp changes in this species number are not characteristic. Hibernation promotes preservation of the most productive part of populations. Two-thirds of young dormice that had no time in autumn to save enough fat, as well as old individuals, may perish during this period. Practically full renewal of a population in the most populated parts of the area occurs in 4 years. Owls are the main predator for the fat dormice.

Economic significance.

The Fat Dormice pick a lot of fruits during feeding but do not use many of the fruits because of their unfit flavor qualities. It harms orchards, nuciferous gardens, and vineyards. The damage made 12.5-41.7%, averaging one-third the yield, in small vineyards of Lenkoran area of Azerbaijan in 1940s. Fat dormice at 30 individuals/hectare destroyed 18% of the yield of wild growing pears in the Caucasian reserve in the same period. As measures of control, killing traps "Nero", arc traps number 1 and 0, and other traps were applied. The essential damage to yield was also marked in 1970s in the Caucasus. However, the Fat Dormouse number is now much lower, and its harm is also not as significant. The nature protection status of the species in the International Union for the Conservation of Nature Red List is classified as Lower Risk/Near Threatened. In the territory of Russia, the Fat Dormouse is brought in Red Lists of rare animal and plant species subjected to protection in Ryazan Region, Mordovia and Chuvashia Republics. Only repellent measures including the use of biophysical devices for protection of vineyards and fruit plantings are recommended in the Caucasus and Carpathian mountains.

Reference citations:

Airapetyants A.A. 1983. Dormice. Life of our birds and animals. N.5. Leningrad: Leningrad State University, 191 p. (in Russian).
Baskevich M.I. 2005. Fat dormouse Glis glis (Linnaeus 1766). [Online] Available at: (in Russian).
Grafodatskii A.S., Fokin I.M. 1993. Comparative cytogenetics of Gliridae (Rodentia). Zoologicheskii zhurnal 72(11): 104.112 (in Russian).
Gromov I.M., Erbaeva M.A. 1995. The Mammals of Russia and adjacent territories. Lagomorphs and Rodents. St. Petersburg: ZIN RAN, 552 p. (in Russian).
Hutchins M., Kleiman D.G., Geist V., and McDade M.C., eds. 2003. Grzimek.s Animal Life Encyclopedia, 2nd edition. Vol. 16, Mammals V. Detroit et al.: Farmington Hills, MI: Gale Group, 586 p.
Likhachev G.N. 1972. Spread of dormice in the European part of the USSR. In: Kucheruk V.V., ed. Fauna and ecology of rodents. N.11. Moscow: Moscow University, p. 71.115 (in Russian).
Lozan M.N. 1970. Rodents of Moldavia (eds. Averin Yu.B. and Gromov I.M.). Vol. I. Kishinev: Izdatel.stvo Akademii Nauk Moldavskoi SSR, 171 p. (in Russian).
Ognev S.I. 1947. Animals of the USSR and adjacent countries. Vol. 5. Moscow & Leningrad: AN SSSR, 809 p. (in Russian).
Pavlinov I.Ya., Rossolimo O.L. 1987. Taxonomy of the USSR mammals. Moscow: Moscow University, 284 p. (in Russian).
Polyakov I.Ya. 1968. The harmful rodents and their control. Leningrad: Kolos, 256 p. (in Russian).

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