Arctic Foxes 'Grow' Their Own Gardens

During the long, dark Arctic winter, the tundra fades into an opaque world where sky and ground blend into a never-ending haze. With temperatures that dip into the double-digit negatives, the only place for the foxes to take shelter and protect young from the elements—and other predators—is deep underground. Some dens are over a century old, and the best are elevated: ridges, mounds, riverbanks. But with so much permafrost—frozen ground—and such a flat environment, prime sites can take years to develop. And since digging new homes wastes valuable energy, real estate is limited—so foxes reuse locations—and in a strange time-share, foxes sometimes steal sites belonging to ground squirrels. With litters averaging about eight to 10 pups—some as high as 16—the foxes deposit high amounts of nutrients in and around their dens, a combination of urination, defecation, and leftover kills. In winter, foxes don’t drink water or eat snow or ice, which lowers their core temperature. Instead they get water from their food, which concentrates nutrients in their urine, making it more potent. continue