The Arctic tundra, a snowy biome that is housed within the Arctic Circle, is characterized by freezing temperatures, strong winds and permafrost. Yet, despite being one of harshest environments on earth, many animals call the Arctic home. So how do animals living in the Arctic, a place that has months of continuous light followed by months of continuous darkness, survive in such a harsh habitat?

Only a limited number of animal species in the Arctic do not migrate or hibernate during the winter months. The ones that do brave the winter have become well adapted to the extreme conditions and are able to survive year round. Some notable adaptations include the following:

Bigger is Better
Polar animals seem to be larger in size, have shorter limbs, denser fur and more fat and blubber than their counterparts in more temperate climates; these characteristics help reduce heat loss. It is also important to note that only larger animals, like the muskox, roam the Arctic in winter and huddle in herds to keep warm.

Dig for Cover
Smaller animals, such as the collared lemming, go under the snow for warmth, shelter and protection. These smaller animals dig elaborate tunnels under the packed snow and live on the roots of plants during the winter months.

Fur Better, not Fur Worse
As the temperature dips, animals replace their summer coats with thicker, longer coats. The snowy owl, for example, is covered in fluffy white feathers from head to toe These feathers are overlapped with more feathers to ensure the owl will remain warm in cold weather. The Arctic fox replaces its brown coat with a heavier white coat that not only keeps it warm, but also provides camouflage. The muskox grows plenty of shaggy, coarse hair that covers everything but its feet.

Tick Tock
A research team in Alaska studied the heart rates of two types of Arctic rodents exposed to continuous daylight, nocturnal porcupines and the Arctic ground squirrel. Despite having no time cues, the animals seemed to respond to something that provided them with regularity and allowed them to retain a normal day/night, 24-hour cycle and a biological clock. So what was the one constant factor that kept the animals’ cycle on schedule in Alaska? It was the sun, which moves overhead in a circular motion and, at midnight, is tipped to the north. The animals are aware of the position of the sun in the sky, and the nearness of the sun to the horizon can act as a clue to animals to maintain a 24-hour cycle.