Squirrels are familiar sights in backyards and parks, often seen darting across lawns or scampering up trees. As colder months approach, many people notice a decrease in their activity, leading to questions about their whereabouts during winter. Despite a common misconception, most squirrels do not fully hibernate in the traditional sense, disappearing completely until spring. They employ various strategies to endure the cold, remaining active, though less visible, throughout the winter season. This article will explore where these resilient rodents find shelter and how they manage to survive the challenges of winter.
Winter Shelters
During winter, squirrels seek well-protected locations to shield themselves from harsh weather and predators. One common shelter is a drey, a nest constructed by tree squirrels high in branches. These spherical structures are crafted from an outer layer of sticks and leaves, with an inner lining of softer materials like moss, grass, and fur to provide insulation and warmth. The interior of a drey can be significantly warmer than the outside air.
Squirrels also utilize natural tree cavities, or dens, which offer superior protection from wind and moisture. These hollow spaces are lined with insulating materials. Tree cavities are preferred for winter use because they are more wind-proof and water-proof than dreys. In urban environments, squirrels may find shelter in human structures such as attics, sheds, or garages.
Survival Strategies for Winter
Tree squirrels, such as gray and red squirrels, do not truly hibernate. Instead, they enter periods of torpor, a shorter-term state where their body temperature, heart rate, and metabolic rate decrease to conserve energy. This allows them to remain less active for days during severe cold spells, but they can awaken to forage when conditions improve.
A survival strategy involves caching food throughout the fall, building up reserves for the lean winter months. Tree squirrels engage in “scatter hoarding,” burying individual nuts and seeds in numerous shallow holes. They rely on spatial memory and keen smell to locate these buried treasures, even under snow. Their diet shifts to stored nuts and seeds, like acorns, walnuts, and pine cones. Squirrels also build up fat reserves in autumn, providing insulation and an energy source.
Variations Among Squirrel Species
The term “squirrel” encompasses diverse rodents, and their winter behaviors vary by species. Tree squirrels, including gray, red, and flying squirrels, remain active throughout the winter. While they reduce activity and enter periods of torpor during the coldest days, they frequently emerge to retrieve cached food and forage. Their survival relies on finding stored provisions and adapting to intermittent cold.
In contrast, many species of ground squirrels, such as chipmunks, marmots, and prairie dogs, are true hibernators. These species spend winter in deep burrows. During true hibernation, their body temperature drops significantly, and their heart rate and breathing slow to minimal levels. They emerge from hibernation in spring, relying on fat reserves. This difference in winter strategy highlights the diverse adaptations within the squirrel family.