(SCIENCE NEWS) – Arctic ground squirrels can survive harsh winters with below-freezing temps by holing up for some eight months without eating. These hibernators "live at the most extreme edge of existence, just barely hovering over death, and we don't fully understand how this works," says Sarah Rice, a biochemist at the University of Alaska Fairbanks.
By snooping on what's going on inside these squirrels, researchers now have a better idea. Nutrients recycled from muscle breakdown help the animals get by during hibernation, Rice and her colleagues report December 7 in Nature Metabolism.
From autumn to spring, Arctic ground squirrels (Urocitellus parryii) hibernate in bouts of deep torpor. In a state akin to suspended animation, the squirrels breathe just once a minute, and their hearts beat five times per minute. Every two or three weeks, the squirrels revive somewhat for about 12 to 24 hours; their body temperatures rise, and the animals shiver and sleep, but don't eat, drink or defecate.
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