If ground squirrels can hole up for months without starving or losing muscle, why can’t we?

Arctic ground squirrels can hibernate for up to eight months. (Courtesy Lesa Hollen/UAF)

A new study from the University of Alaska Fairbanks uncovers how arctic ground squirrels recycle nutrients to stay healthy during their long hibernations.

Sarah Rice is the lead author of the paper and a Ph.D. student at UAF’s Institute of Arctic Biology. She says during the winter, arctic ground squirrels enter a state of extreme hibernation.

“They can take their body temperature below freezing,” Rice said. “When they’re in hibernation their heartbeats five times a minute, and they breathe once a minute. They’re just this incredible animal. It’s almost like in a suspended state of animation.”

Arctic ground squirrels can hibernate for up to eight months — and they appear to wake from their winter sleep without starvation or muscle loss. Rice wanted to know how they stayed in such good shape without exercise or food.

The study found that the squirrels’ bodies transformed existing nutrients into resources that could be used to build back tissue that atrophied during hibernation.

To do the study, Rice and her colleagues collected squirrels, brought them to a lab, and introduced them to the cold, dark conditions that induced hibernation. Then the scientists sampled the hibernating animals’ blood to track how nutrients in their bodies changed over time.

“We go into this cold chamber with a little headlamp on,” Rice said. “And we run our experiments on the animal, just going super slow, and super carefully, so we don’t wake them up. And then we put them back on the shelf, and you’re just in this dark room surrounded by like 30 hibernating animals the entire time. It’s just dead quiet.”

If people stayed long enough in one very cold place without food or exercise, they wouldn’t survive the starvation or muscle atrophy that would occur. But if people could recycle nutrients like arctic ground squirrels do, it could keep people on bed-rest healthier or allow astronauts to travel to space with fewer resources.

According to Rice, researchers think they may be able to borrow some of the science of animal hibernation to benefit people.

“Hibernation is a model that has found solutions to problems in the world,” Rice said. “It’s able to survive extremely long fasting at extremely cold temperatures. And so if we can understand some of these mechanisms of resilience, maybe we can take that and apply it to human medicine.”

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