Foxes are highly adaptable mammals found across diverse environments, from forests and prairies to urban areas. They do not migrate for winter; instead, they employ various strategies to survive the colder months, demonstrating their resilience.
Winter Denning Habits
When winter arrives, foxes adapt their living arrangements. They often seek existing shelters for warmth and protection from harsh weather. This includes abandoned burrows from other animals, such as badgers or rabbits. Foxes may also utilize natural shelters like rock crevices, hollow logs, or dense brush piles. In areas with human presence, they might find refuge in structures like sheds or culverts.
While foxes do not typically dig elaborate new dens for winter, they may expand or deepen existing burrows for insulation. For instance, red foxes might modify an abandoned woodchuck burrow, which can be extensive, sometimes reaching up to 75 feet long with multiple entrances. These dens provide a secure resting place and can also serve as food storage. However, adult foxes often sleep in the open, even in snow, unless severe storms drive them to seek shelter.
Physical and Behavioral Changes for Cold
Foxes exhibit physical and behavioral adaptations to cope with cold temperatures. A significant physical change is the growth of a thicker, denser winter coat, known as pelage, which provides superior insulation. This coat can become so thick that it extends to their footpads, aiding in heat retention. Arctic foxes, for example, develop a double-layered fur with a dense undercoat and longer guard hairs, allowing them to maintain body temperature even at extremely low temperatures.
Behaviorally, foxes conserve body heat by curling up tightly into a ball, often tucking their noses under their bushy tails. Their long, furry tails act as an insulating layer. Some species, like the Arctic fox, have compact bodies with shorter muzzles, ears, and legs, which reduces the surface area exposed to the cold and minimizes heat loss. While they remain active, their activity levels might decrease during the coldest parts of the day or night to conserve energy.
Scavenging and Hunting in Snow
Finding food during winter can be challenging, but foxes are skilled opportunists. Their keen senses, especially hearing, are important for hunting prey hidden under snow. Foxes can detect the subtle movements of small rodents, like mice or voles, beneath a thick layer of snow, sometimes hearing them from a football field away. Once prey is located, they employ a distinctive “mousing” technique, which involves leaping high into the air and pouncing headfirst into the snow to capture the unsuspecting animal. This precise leap can be calculated using cues that may include the Earth’s magnetic field, increasing their success rate.
When natural prey is scarce, foxes will also scavenge for carrion. This opportunistic feeding strategy is important in winter. Urban foxes may forage near human settlements, looking for food in compost bins or raiding bird feeders. Foxes also have the ability to cache, or store, surplus food during times of plenty. They dig shallow holes, typically 5-10 cm deep, to bury small portions of food, which they can later retrieve using their memory and sense of smell. This practice provides a reserve when hunting becomes difficult.