The Dormouse Hollow

Dormouse Biology

General Biology: Gliridae

Dormice (Gliridae, Rodentia, Mammalia)

Genus GLIS Brisson, 1762
Genus MYOXUS Zimmermann, 1780

Fat Dormouse, or Edible Dormouse

The single species, Myoxus glis, occurs from France and northern Spain to the Volga River and northern Iran and on the islands of Sardinia, Corsica, Sicily, Crete, and Corfu (Corbet 1978); it also is present in England as the result of introduction. Use of the name Myoxus in place of the frequently applied Glis Brisson, 1762, is in accordance with Holden (in Wilson and Reeder 1993).

Head and body length is 130-90 mm, tail length is 110-50 mm, and weight is 70-180 grams (Van Den Brink 1968). The short, soft, thick pelage is silvery gray to brownish gray on the upper parts, lighter on the flanks, and white or yellowish on the underparts. This squirrel-like animal has large and rounded ears, small eyes, and a long, densely bushy tail. The hands and feet, with their rough pads, are adapted for climbing. Females have 10 or 12 mammae (Ognev 1963). Except as noted, the information for the remainder of this account was taken from Grzimek (1975) and Ognev (1963).

The edible dormouse inhabits deciduous or mixed forests and fruit orchards in both lowlands and mountains. Its populations in any given area are partly dependent on the existence of a suitable number of hollow trees as these are the most common sites for daily shelter, hibernation, and natal nests. The hollows may be heavily lined with grass or other vegetation, especially if being used for hibernation or rearing of young. Myoxus also shelters in crevices between rocks, burrows among tree roots, woodpecker holes, piles of mulch, attics, barns, and artificial nest boxes. Hibernation burrows sometimes are 50-100 em below the surface of the ground.

The edible dormouse is primarily nocturnal and crepuscular, though occasionally it is active by day. It is highly arboreal, and its agility in the trees may exceed that of squirrels. Some of its leaps have been reported to cover 7-10 meters. It has exceptionally good senses of vision, hearing, smell, and touch (through its vibrissae). Individuals visit many trees each night in search of food. If a food shortage occurs, there may be movement to a different area. During winter hibernation Myoxus sleeps on its side or back and curls its body so that the feet touch the muzzle. The hibernation period is very long, with the animals entering torpor from September to November and emerging from early May to early June. The diet consists mainly of seeds, nuts, acorns, berries, and soft fruits. Insects may be important at certain times, and small birds are taken on rare occasions.

The population density in the northern Caucasus was calculated at 30/ha. In Moravia, however, Gaisler, Holas, and Homolka (1976) found a minimum density of only 1/ha. and an individual home range diameter of about 200 meters. The edible dormouse is apparently territorial and marks its space with glandular secretions. It is highly vocal; a variety of chirps, whistles, squeaks, and squeals have been noted. Individuals are quarrelsome, and males are reported to fight savagely during the breeding season. Nonetheless, small groups may hibernate together, and as many as eight individuals have been found in a single tree hollow. In studies of captives, males have been observed to remain in the vicinity of females after mating and to be allowed back into the nest about 16 days following birth, where they help to clean and protect the young. Families may stay together through winter hibernation; a wild male, however, probably leaves a female after mating in order to pursue other estrous females.

The mating season extends from June to early August. In Moravia the young are born in August and early September (Gaisler, Holas, and Homolka 1976). Although two litters per year have been reported in some areas, the very short active season of Myoxus suggests that a single annual litter per female is the usual case. Gestation periods of 20-30 days have been reported. Litter size is 2-10 young, and the average in Gaisler, Holas, and Homolka's (1976) study was 4.5. The young are born naked and blind, open their eyes and are weaned after about 4 weeks, and do not begin to mate until after their first hibernation. Wild individuals have been known to live more than 4 years, and a captive lived 8 years and 8 months (Jones 1982).

In some areas Myoxus is considered extremely harmful to the production of fruit and wine. It consumes large amounts of apples, pears, plums, and grapes and has been reported to destroy one-third of the grape crop in the northern Caucasus. However, it is easily trapped, there is some demand for its luxuriant fur, and it is hunted for use as food and a source of fat. In ancient Rome Myoxtis was considered a delicacy, and colonies were kept in large enclosures planted with nut-bearing bushes and provided with nesting sites. Prior to a feast, individual animals would be confined to earthen urns and fattened on acorns and chestnuts. The meat of Myoxus is still a gourmet dish in some parts of Europe. About 1902 the genus was deliberately introduced in southeastern England, where a population now is established (J. E. Jackson 1994). Notwithstanding its great range, Niethammer (in Grzimek 1990) noted that it remains common only in some areas. Pucek (1989) indicated that Myoxus has become rare in much of Europe through destruction of forest habitat. It is now designated as near threatened by the IUCN.

Information taken from: Nowak, R.M. (Ed.). Walker's Mammals of the World. 6th Edition. The John Hopkins University Press. Baltimore and London, 1999.