The Arctic fox (Vulpes lagopus), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome.
It is well adapted to living in cold environments, and is best known for its thick, warm fur that is also used as camouflage. It has a large and very fluffy tail. In the wild, most individuals do not live past their first year but some exceptional ones survive up to 11 years. Its body length ranges from 46 to 68 cm (18 to 27 in), with a generally rounded body shape to minimize the escape of body heat.
Arctic Fox Adaption
The Arctic fox lives in some of the most frigid extremes on the planet, but they do not start to shiver until the temperature drops to −70 °C (−94 °F). Among its adaptations for survival in the cold is its dense, multilayered pelage, which provides excellent insulation.
Additionally, the Arctic fox is the only canid whose foot pads are covered in fur. There are two genetically distinct coat color morphs: white and blue. The white morph has seasonal camouflage, white in winter and brown along the back with light grey around the abdomen in summer. The blue morph is often a dark blue, brown, or grey color year-round. Although the blue allele is dominant over the white allele, 99% of the Arctic fox population is the white morph. Two similar mutations to MC1R cause the blue color and the lack of seasonal color change. The fur of the Arctic fox provides the best insulation of any mammal.
The fox has a low surface area to volume ratio, as evidenced by its generally compact body shape, short muzzle and legs, and short, thick ears. Since less of its surface area is exposed to the Arctic cold, less heat escapes from its body.
The Arctic fox has a functional hearing range between 125 Hz–16 kHz with a sensitivity that is ≤ 60 dB in air, and an average peak sensitivity of 24 dB at 4 kHz. Overall, the Arctic foxes hearing is less sensitive than the dog and the kit fox. The Arctic fox and the kit fox have a low upper-frequency limit compared to the domestic dog and other carnivores. The Arctic fox can easily hear lemmings burrowing under 4-5 inches of snow. When it has located its prey, it pounces and punches through the snow to catch its prey.
The Arctic fox also has a keen sense of smell. They can smell carcasses that are often left by polar bears anywhere from 10 to 40 km. It is possible that they use their sense of smell to also track down polar bears. Additionally, Arctic foxes can smell and find frozen lemmings under 46–77 cm of snow, and can detect a subnivean seal lair under 150 cm of snow.