Wonders of God’s Creation

An Arctic Lesson in Cool You might think you’re cool, but the arctic ground squirrel is supercool. No, wait. Sorry, I’ve got that wrong. It says here that the arctic ground squirrel is capable of supercooling. My editor insists that’s “a fundamentally different thing.” God designed this variety of squirrel to hibernate in a unique way. In Denali, Alaska, ground squirrels are only active for about five months out of the year. They spend the other seven months . . . well, frozen. That’s right—when arctic ground squirrels hibernate, their body temperature drops below freezing (a process known as supercooling). We’ve yet to find another mammal capable of getting so cold without dying, and we’re not even sure exactly how or why these squirrels can do it. We do know that, every few weeks, these hibernating squirrels spend about half a day shivering and shaking to get their body temperatures back up to 98 degrees Fahrenheit. Without that brief temperature boost, oxygen deprivation would severely damage their brains. After hibernation is over, the squirrels have only a handful of months to eat, breed and fatten up for the next winter. Then it’s back to supercooling. Pictured: arctic ground squirrel (Urocitellus parryii) Photo by James Capo Text by Jeremy Lallier and James Capo