Marvels of an Arctic Winter | America's National Parks

As the months of winter pass, only the heartiest of creatures will be able to survive out in the open, seemingly resigned to their fate. But under the tundra, some creatures are pulling off a small biological miracle. The hibernating ground squirrel's body temperature has actually dropped below freezing. Every 2 to 3 weeks, he'll start to shiver, warming himself back up to normal temperatures—a mysterious key to his survival.

The winter's sun barely breaks the horizon, and during the almost perpetual night of the Arctic winter, temperatures can plummet to lower than 50° below zero. The fantastical northern lights billow and twist all winter above the Brooks range. Some native peoples believe the northern lights are the dancing spirits of the dead. Science has an equally otherworldly explanation: these sheets of light happen when charged particles from the sun, caught by the Earth's magnetic field, stream down at the poles where they react with the atmosphere. Either way, they are enchanting.

Finally, it's early spring. After about 7 months, the Arctic squirrel shivers himself awake, ending his long hibernation ordeal. He's lost about half his body weight and wakes up hungry for food and female companionship.