This week we take a closer look at hibernation and how it works. We speak with Kelly Drew, a neuroscientist at the University of Alaska Fairbanks, who studies the Arctic ground squirrel, the "Usain Bolt" of hibernators. And we talk with Frank van Breukelen, a biologist at the University of Nevada, Las Vegas, who studies an animal who isn't very good at hibernating: the tenrec.

This episode is hosted by Bethany Brookshire, science writer from Science News.