Hazel Dormouse in Focus

Vegan Life takes a closer look at this endangered mammal – the hazel dormouse


The dormouse (muscardinus avellanarius) is one of Britain’s most endangered mammals. This fluffy rodent can easily be distinguished from other mice by their long, fluffy tails. They have bright golden fur on their back and a pale cream-coloured underside. Once widespread throughout the country, hazel dormice declined in both population and distribution during the 20th century, largely due to the loss of habitat. They now have a patchy distribution, primarily in southern England and Wales with some areas of reintroduction in the north of England and Scotland. They are highly arboreal, spending most of their time high off the ground, feeding along the branches of trees and shrubs and rarely travelling further than 70 metres from their nest.


• People’s Trust for Endangered Species [PTES] published a report, the ‘State of Britain’s Dormice ’ in 2016, which revealed that Britain’s native hazel dormouse has declined by a third since the start of the 21st century. The report also found that hazel dormice have become extinct in 17 English counties since the late 1800s.


• Ian White, PTE’S dormouse officer, said: “Over the past 100 years dormice have suffered from the loss of woodlands and hedgerows, as well as changes to farming and woodland management practices. Dormice populations are also vulnerable to climatic changes, in particular wetter springs and summers when foraging for food becomes harder, and when warmer winter temperatures interrupt successful hibernation.”


• Dormice are fully protected by UK law under the Wildlife and Countryside Act. It’s a crime to disturb, injure or kill them in their nests, or collect, trap or sell them without a licence.


• Dormice weigh as little as two £1 coins.


• During hibernation, dormice slow down their bodily functions and enter an extreme state of torpor. In this state they feel cold to the touch and take some time to rouse themselves when handled.


• Dormice are omnivores and typically feast on flowers, nectar, hazelnuts and insects. They are successional feeders and require a range of foods to allow them to feed while they are active.


• According to Ian, during the summer dormice will take advantage of caterpillars, aphids and wasp galls and they fatten up for hibernation on fruits and berries such as blackberries and hazelnuts.


• Ian said: “Wood mice, bank voles and hazel dormice feed on hazelnuts by gnawing a round hole in the shell and each leaves distinctive marks. The tooth-marks of dormice run parallel to the edge of the hole, rather than outwards from its centre, so that the rim looks smooth, and there are few toothmarks elsewhere on the nut. In contrast, the toothmarks of mice and voles run outwards, so that the rim of the hole looks like the milled edge of a coin.”


• Males tend to come out of hibernation earlier than females – and go into hibernation sooner. That means females have only six months to recover the weight they have lost during hibernation, get to a suitable body condition to breed, have young and then put weight on to enable them to survive another hibernation.


• According to Ian, dormice become sexually mature at one year old .He said :“The average litter size is four and these are typically born in late July, August or September .Litters may be born as early as late May or early June but this is unusual .Dormice will usually just have one single litter but those who breed early may be able to have a second.”


• Ian added :“The gestation period for a hazel dormouse is about three and a half weeks and the young remain with their mother for about four weeks .For a small rodent this is a long period of maternal care.” • They must reach weights between 15-18 grams before hibernating for the first time ;otherwise their chances of surviving the winter are poor.


Photography: Claire Pengelly


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