By Alex Kirby BBC News Online environment correspondent

One of the UK's most appealing mammals, the dormouse, is at risk because it dislikes getting wet.

Scientists say dormice are strongly influenced by the weather, and also by the kind of woodland they inhabit.

Our work shows that dormouse populations are strongly affected by the weather

Research team

The animals usually sleep for eight months of the year. They are orange-brown in colour, weigh about as much as three pound coins and measure about three inches (seven centimetres), with tails almost the same length.

There are thought to be about 10,000 dormice in southern England, the one part of the UK - with Wales - where they survive despite continuing habitat loss. Nationally, they have disappeared from more than half of their historic range.

Hungry but dry

The scientists, Fiona Sanderson and Dr Paul Bright of Royal Holloway College, University of London, say both weather and habitat can make a difference to the animals' survival rates.

They prefer to live in hedgerows and ancient woodland, and eat fruit, nuts and flowers.

Blackberries can be bad news

"This is crucial for dormice, as the timing of tree fruiting and flowering determines how much food they have, and hence when they can breed and whether or not they can fatten up enough to survive hibernation.

"Our work shows that dormouse populations are strongly affected by the weather, and are affected in different ways at different sites.

"For dormice living in woodland dominated by honeysuckle and hawthorn, which flower in spring and early summer, populations increase following a warm summer.

"Dormice living in woods where hazelnuts and blackberries are their major food supply, however, are badly affected after a warm and wet autumn."

Time to spare

The explanation is simple - dormice appear not to like foraging for food in the rain.

A warm summer, though, means both that more food is available, and that the animals sleep less and so have more time for eating and breeding.

Earlier work by the pair found that dormouse numbers in northern England and upland Wales had halved since 1993.

Future research will look at patterns of weather and torpor in dormice to see if climate change can explain their decline.

Dr Tony Mitchell-Jones of English Nature told BBC News Online: "The dormouse does seem to be on the edge of its climatic range in the UK.

"We think climatic variation, coupled with the fragmentation of woodland, is an important feature in its decline.

"Small isolated populations can become locally extinct. We're restoring hedgerows and small woods, to link these groups, and we're ensuring that habitats are properly managed."

Images courtesy of John Robinson/English Nature