Dormouse fact file

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Facts about hazel dormice – how many did you know?


  • Dormice are nocturnal (mainly active at night) and arboreal (live in trees).
  • Dormice hibernate from about October to April. The only other UK mammals that hibernate are hedgehogs and bats. Dormice hibernate on the ground, where the temperature is more stable.
  • The average healthy dormouse weighs around 20g, but they can be as heavy as 35g just before hibernation.
  • Dormice eat the flowers from oak, hawthorn, sycamore, willow, honeysuckle and bramble. In summer they eat caterpillars, aphids and wasp galls before fattening up on blackberries and hazelnuts ready for hibernating.
  • They can live up to five years, which is a long time for a small rodent.
  • Dormice prefer the new growth that appears after traditional woodland management, such as coppicing. They can also be found in scrub habitat and old hedgerows.
  • Not many animals prey on dormice. Badgers and wild boar may eat them when dormice are hibernating.
    Their greatest threats are the removal or inappropriate management of hedgerows and woodland. It is also a challenge for them to survive hibernation in Britain’s mild, wet winters.
  • Hazel dormice are rare and vulnerable to extinction in the UK. They are protected under the Wildlife and Countryside Act 1981.

You can play a vital role in protecting dormice by sponsoring a dormouse house for just £5 a month. This will help keep threatened dormice safe and help us release new populations in counties where they have become extinct.

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