Navigation Links
Sleeping through danger: the dormouse approach to survival

The dormouse in Alice in Wonderland was well advised to stay asleep especially as doing so did not prevent it from taking a full part in the tea-time conversation. Dormice in Europe spend about eight months of the year asleep and are extremely safe during this extended period, with almost all of them surviving the winter. This result comes from a study of dormouse survival rates in Austria, the Czech Republic, England, Germany and Italy.

Karin Lebl was a PhD student in Ruf's group. Together with collaboration partners in these countries, she examined how the survival of dormice living in the wild varies according to a number of factors, including the time of the year, various climatic factors and the animals' reproductive behaviour. In contrast to some species of marmot, for which hibernation is known to be associated with high mortality rates, the dormouse seems well able to accumulate enough fat reserves to survive even the harshest winter. Nevertheless, the work of Ruf's group showed that dormice in all five study countries are particularly vulnerable in early spring, immediately after they awake from hibernation. The animals clearly lose weight as a result of spending eight months without food, so afterwards they spend a large amount of time foraging, which presumably makes them more susceptible to predators: owls, weasels, pine martens and both wild and domestic cats.

The risk of having young

Unusually for small mammals, dormice do not breed every year. Instead, they "save" their reproductive efforts for years when there are good supplies of acorns or beech nuts. Such events occur irregularly and at different rates: in Germany, for example, seeding is considerable more frequent than in the study area in the northern Italian Alps. Lebl and Ruf found that mortality rates were significantly higher in years when the animals had young than in years when they did not. This may relate to the increased time the parents spend looking for food for their young or it may stem from the direct energy costs of reproduction. The upshot, though, is that dormice in "good" habitats in Germany, where oaks and beech trees frequently produce seeds, live on average for less than four years while dormice in the "poorer" habitats in northern Italy live on average for more than twice as long. Perhaps because they expect to die younger, German dormice tend to have larger litters than their longer-lived Italian cousins. Even so, dormice in Germany simply do not have time to produce the same number of young in their lifetimes as dormice in Italy.

So why do dormice in the Italian Alps live for so long? As Ruf says, "we can't really explain it. Despite what we may think, differences in the climate cannot account for our results and we have no evidence to suggest that climate change is having any effect on the animals' survival. Our working hypothesis is that the major factor influencing the dormouse population is the type and number of predators. Maybe there are fewer predators in Italy or perhaps the Italian dormice have particularly successful methods for avoiding being eaten."


Contact: Professor Thomas Ruf
University of Veterinary Medicine -- Vienna

Related medicine news :

1. National Sleep Awareness Week(R) (March 7-13): How Are You Sleeping?
2. Sleeping well at 100 years of age: Study searches for the secrets to healthy longevity
3. Our children arent sleeping and were medicating them
4. Most Babies Start Sleeping Through Night at 2 to 4 Months
5. Scientists seek urgent treatment for fatal sleeping sickness
6. Toys"R"Us, Inc. Expands its Support of Autism Speaks Throughout North America
7. CVS/pharmacy Begins Free Health Screenings in Communities Nationwide Through A Su Salud Program
8. Human Dental Technology Leads to Breakthroughs for Pet Dental Health at Sergeants Pet Care Products, Inc.
9. Southridge LLC Provides Equity Capital Through Private Agreement with PuraMed Bioscience
10. HITSP Contract With U.S. HHS Extended Through April 2010
11. First Breakthrough in Water Heating Technology!
Post Your Comments:
(Date:11/27/2015)... ... 2015 , ... An inventor, from Hopkinsville, Ky., thought there ... home, so he invented the patent-pending ELECTRONIC M.D. , The ELECTRONIC M.D. provides ... so, it could help to prevent potential overdose situations. As a result, it ...
(Date:11/27/2015)... , ... November 27, 2015 , ... ProSidebar: Fashion ... Final Cut Pro X. With ProSidebar: Fasion, video editors can easily add an ... as a minimalist title opener. Utilize presets featuring self-animating drop zones, lines, bars, ...
(Date:11/27/2015)... ... ... A simply groundbreaking television series, "Voices in America", which is hosted by Hollywood ... issues that are presently affecting Americans. Dedicated to providing the world with a wide ... subjects consumers focus on, one episode at a time. , In the latest ...
(Date:11/27/2015)... ... November 27, 2015 , ... The men and ... nonprofit healthcare organizations in the country. They have overseen financial turnarounds, shown commitment ... advance the healthcare industry as a whole through their advocacy and professional efforts. ...
(Date:11/26/2015)... ... November 26, 2015 , ... ... in central Michigan, have come together on Thanksgiving Day to share the things ... for viewing on the Serenity Point YouTube channel, patients displayed what they wrote ...
Breaking Medicine News(10 mins):
(Date:11/27/2015)... Nov. 26, 2015 ... of the "2016 Global Tumor Marker ... Volume and Sales Segment Forecasts, Innovative Technologies, ... report to their offering. --> ... the "2016 Global Tumor Marker Testing ...
(Date:11/26/2015)... Nederland, November 26, 2015 ... Een nieuwe aanpak combineert immunotherapie met Bremachlorin-photodynamische ... ) --> ...      (Photo: ) ... Universitair Medisch Centrum (LUMC) blijkt ...
(Date:11/26/2015)... , November 26, 2015 ... addition of the "2016 Future Horizons ... of Abuse Testing Market: Supplier Shares, Country ... report to their offering. --> ... the "2016 Future Horizons and Growth ...
Breaking Medicine Technology: