The arctic fox (also known as the snow fox or polar fox) survives some of the most extreme temperatures on Earth. The bottoms of its paws are covered in fur, insulating it from the elements. Its body is small, only 46-68 centimeters (18-27 inches) in length, and rounded to minimize surface area and maximize heat.
Blood flow to the paws is regulated independently from its core temperature, allowing the arctic fox to keep its paws above the tissue freezing point even if its core temperature drops.
The arctic fox does not hibernate, but instead increases its body weight up to 50% in preparation for winter. It eats everything from rodents, birds and fish to seaweed and berries, scavenging off carcasses killed by polar bears and wolves.
How do you take a nap during the arctic winter? The arctic fox minimizes its surface area even further, curling into a ball and using its tail as a blanket. It seeks places out of the wind, burrowing into its den and conserving fat by reducing activity.
But how cold does it get? The arctic winter is usually around -34° C ( -30° F) and can drop below −50° C (−58° F). The temperature can even drop to −70° C (−94° F). This is the point when the arctic fox will finally begin to shiver.
“Is that all you’ve got? I’m still nice and toasty in here. Bring it.”
How does the cute little bastard do it? The answer is this: the arctic fox has the warmest coat of any mammal in the world. Fur thickness increases by 140% as the arctic fox changes from its brown summer coat into this fashionable white winter ensemble. The coat is dense and multilayered, designed to trap heat. Each shaft of hair is hollow, filled with air warmed by the fox’s body heat: the most high-tech winter wear in the animal kingdom.
And it does all this at only 3.5 kilograms (7.7 pounds)!