Why animals don’t freeze during winter hibernation?

The question seems simple, but scientists could not understand how bears, bats, snakes and other animals survive the winter, not freezing to death.

Чому тварини не мерзнуть під час зимової сплячки?

According to a new study, animals that hibernate do not feel the winter cold as we are, informs Rus.Media.

“If you put neurons of the mouse or human cold, they will start working… like crazy,” says senior study author Elena Gracheva, a neurophysiologist from the Yale school of medicine (USA). But when Grachev and her colleagues put some of the animals running into hibernation, such as trinadcatiletnie ground squirrel and the Syrian hamster, in the cold, they noticed a very low activity at the TRPM8 channel, region of the Central nervous system that processes information about cold.

In another laboratory experiment, researchers gave ground squirrels, hamsters and mice are two platforms to choose from – one c temperature 30 degrees Celsius, another – c a temperature in the range from +30 to 0 degrees Celsius.

While animals hibernate, is preferred a warm platform, they also used cold, apparently, not feeling the temperature change.

Mouse responded on a cold platform differently. “They touched it with one paw, as if to say: ooh, don’t want to go there, too cold” – says Grachev. Touching times to the cold platform, the mouse did not touch her anymore.
So, what is the cause of differences in behavior of mice, gophers and hamsters?

First Gracheva and her colleagues hypothesized that animals that hibernate are less sensitive to cold cells in the nervous system. But after opening several ranges of animals, the team found that ground squirrels and hamsters were approximately the same number of these cells just in the first case, sensitivity to cold was less. To survive the winter or lack of food, animals pass through a series of physiological changes such as decrease in body temperature, rate of heartbeat and respiratory rate. Thus, it is not surprising that animals that hibernate have developed techniques within the Central nervous system, which helps their bodies to cope with the cold.

According to Brian Barnes, Director Institute of Arctic biology at the University Aljaskinskogo in Fairbanks, loss of sensitivity, which describes the new study is interesting for another reason: feeling cold is one of the ways by which the animal understands that it is time for slumber.
Grachev hopes to learn more secrets of hibernation in the next draft, in which the genes responsible for cold tolerance of squirrels and hamsters, transplantion in mice.

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