The Hibernator's Guide to the Galaxy

Scientists are on the verge of figuring out how to put humans in a state of suspended animation. It could be the key to colonizing Mars.

- By Brendan I. Koerner. Ilustration by Ori Toor

One day in 1992, near the northern pole of a planet hurtling around the Milky Way at roughly 500,000 miles per hour, Kelly Drew was busy examining some salmon brains in a lab. Her concentration was broken when Brian Barnes, a zoophysiology professor from down the hall at the University of Alaska Fairbanks, popped by her bench for a visit. With a mischievous grin, he asked Drew-a neuropharmacologist early in her career to hold out her hands and prepare for a surprise. A moment later, she felt a hard, furry lump deposited in her palms. It was some sort of brown rodent with dagger-like claws, curled up into a tight ball and so cold to the touch that Drew assumed it was dead. To her astonishment, Barnes gleefully explained that it was actually in perfect health.

The creature, an Arctic ground squirrel, was just hibernating, as it does for up to eight months of the year. During that span, the animal's internal temperature falls to below 27 degrees Fahrenheit, literally as cold as ice. Its brain waves become so faint that they're nearly impossible to detect, and its heart beats as little as once per minute. Yet the squirrel remains very much alive. And when spring comes, it can elevate its temperature back to 98.6 degrees in a couple of hours.

Drew cradled the unresponsive critter in her hands, unable to detect even the faintest signs of life. What's going on inside this animal's brain that allows it to survive like this? she wondered. And with that question, she began to burrow into a mystery that would carry her decades into the future.