To survive winter and lack of food, these animals go through an array of physiological changes, such as reducing their body temperature, heart rate, and breathing rate. Life and Deathįor hibernators, tolerating cold is more than a good party trick. “They may feel the cold a little bit, but my speculation is that maybe they just don’t care,” she says.

Instead, after dissecting some of the animals' spines, the team found that squirrels and hamsters have around the same number of these cells-it’s just that their sensitivity to cold seems to be turned way down. Originally Gracheva and her colleagues hypothesized that perhaps hibernators have fewer cold-sensing cells in their nervous system. So, what accounts for the differences in behavior among mice, ground squirrels, and hamsters? ( Read about the surprising origins of Syrian hamsters.) In fact, after the first experience with the cold platform, the mice never touched it again. This is too cold for me,’” says Gracheva, whose study appears December 19 in the journal Cell Reports. “They touch it with one paw and say, ‘Uh-uh, I don’t want to go there. Unauthorized use is prohibited.īut the mice reacted much differently to the cold platform. While the hibernating animals showed a preference for the warm platform, they also explored the cold platforms, seemingly unaffected by the changes in temperature.

In another laboratory experiment, the scientists gave ground squirrels, hamsters, and mice a choice of walking on two platforms-one that was a balmy 86 degrees Fahrenheit and another that varied from 86 degrees down to 32 degrees, the freezing point. ( Read how hibernating bears keep weirdly warm.)īut when Gracheva and her colleagues exposed hibernators like the 13-lined ground squirrel and the Syrian hamster to low temperatures in the lab, they saw very little activity in their TRPM8 pathway, an area of the central nervous system known to process information about cold. like crazy,” says senior author Elena Gracheva, a neurophysiologist at Yale University School of Medicine.

“If you expose mouse or human neurons to cold, they start to fire. It might seem like a simple question, but scientists have long wondered exactly how bears, bats, snakes, and many other creatures can wait out the winter without freezing to death.Īccording to a new study, that may be because hibernating animals don’t feel winter’s chill in the same way that we do.

Do birds hibernate under snow