Dormouse

Lore & Background

Dormice are small, mouse-like rodents with furred tails, largely arboreal and agile. They have an excellent sense of hearing and communicate with various vocalizations. They are omnivorous, feeding on berries, flowers, fruits, insects, and nuts, and are unique among rodents in lacking a cecum. Their dental formula resembles that of squirrels, often lacking premolars. They breed once or occasionally twice a year, with litters averaging four young after a gestation of 22–24 days. Young are born hairless and helpless, opening their eyes about 18 days after birth, and become sexually mature after their first hibernation. Dormice live in small family groups with home ranges that vary by species and food availability. In temperate zones, dormice hibernate for up to six months or longer, sometimes waking briefly to eat stored food. They accumulate fat during summer to sustain them through hibernation. The European edible dormouse (Glis glis) was considered a delicacy in ancient Rome, raised in special enclosures called gliraria, and is still eaten in Slovenia and parts of Croatia. Dormouse fat was believed by Elizabethans to induce sleep.

Reader's Guide

Dormice have a notable evolutionary history, likely originating in Europe with the earliest genus Eogliravus from the Early Eocene of France. They diversified considerably during the Oligocene and reached an apex of diversity in the late Early Miocene, when 18 genera and 36 species existed in Europe alone, making them the dominant rodent group there. Modern genera emerged during the Miocene, and African Graphiurus diversified during the Pliocene. Several lineages experienced insular gigantism on Mediterranean islands, with the largest being the rabbit-sized Leithia of Sicily and Malta. Their significance extends to human culture: the European edible dormouse was a Roman delicacy, and dormice have recently entered the exotic pet trade, with the woodland dormouse (Graphiurus murinus) being most common. The family currently comprises 29 extant species in three subfamilies and nine genera, with extinct genera known from the Eocene through Miocene. The word 'dormouse' likely derives from Middle English, possibly from Old Norse for 'benumbed' and Middle English for 'mouse', though a connection to French 'dormir' (to sleep) is uncertain.

Did You Know?

• Dormice are unique among rodents in lacking a cecum, a part of the gut used to ferment vegetable matter.
• The European edible dormouse (Glis glis) was raised in special enclosures called gliraria in ancient Rome.
• The earliest dormouse genus, Eogliravus, is known from the Early Eocene of France, around 48–41 million years ago.
• The largest dormouse ever known was the rabbit-sized Leithia of Sicily and Malta.