How Hibernation Helps Late Bloomers

For hibernating mammals, gathering enough food during the pre-winter months is crucial to being able to last until spring. That could not be more true for the garden dormouse, whose offspring are born late in the year and thus have much less time to accumulate sufficient energy reserves, according to a new study. But scientists have found that the power of the power nap helps these late bloomers overcome these unfavorable odds.

Given that garden dormice - which are actually is more like a squirrel than a mouse, despite what its name suggests - are born late in the game, that gives them less time to search for and store food for the cold winter months. During hibernation, dormice enter into "torpor" to save energy and water, and this is a strategy they use when food availability is limited.

Scientists from the Research Institute of Wildlife Ecology at the Vetmeduni Vienna compared two groups of juvenile dormice born late in the season - one able to feed freely and the other intermittently fasted on alternate days. The team discovered that fasting dormice used torpor significantly more than the other group enabling them to maintain high growth rates and accumulate sufficient fat reserves.

"The longer an animal stays in torpor, the more energy it saves," Sylvain Giroud, who led the study, said in a statement.

Late spring is family time for garden dormice, according to the National Wildlife Federation. That's when moms have their babies - usually three to eight of them each.

There are 29 different species of dormice, most of them living in forests in Europe, though some are found in Asia and Africa. The way to distinguish garden dormice from the rest is by their big ears, black eye markings, and white tassels on the tips of their tails.

Garden dormice can live up to five years - which is considerably long for a rodent - and this new study indicates that hibernation may play a part in their longevity.

The scientists found a link between higher body temperature (euthermic) while hibernating and aging. This was evidenced by the shortening of the mice's telomeres, which are the caps on the ends of DNA and an indicator of aging.

"Torpor was only viewed as a means to save energy and water, but during the last decade other functions have emerged. These include promoting growth during early life and fattening prior to hibernation, as well as slowing ageing processes" added Giroud.

The findings were published in the journal Proceedings of the Royal Society B.