Squirrels have a superb level of endurance against cold weather, and some squirrels can withstand sub-degree weather. But how is this possible? What happens when the frigid winter temperatures drop? Most mammals have extra layers of fat to help them endure the cold temperatures. Do squirrels rely on fat stores, or do they have other ways to help them live through the winter? Here is what we found to help explain the answer to where do squirrels go in the winter.
Where Do Squirrels Go in the Winter: Survival Methods
Since squirrels don’t migrate to warmer weather, their priority is to survive. Sleeping and eating take up most of the squirrel’s time in the winter.
To survive the winter, squirrels use most of their time eating and sleeping with very little activity.
Most squirrels have in common that they eat a lot before winter, usually the Fall, to increase their body fat to keep them warm. Some squirrels even have changes to their fur to provide extra warmth, in addition to bushier tails. You will also see some critters with ears that have long tufts of hair, and Squirrels have built-in earmuffs.
Tree Squirrels & Flying Squirrels
Like Fox squirrels, Red Squirrels, Eastern grey squirrels, and Flying squirrels do not hibernate. They maintain a constant body temperature throughout the seasons and enter into a dormant state which means they are temporarily inactive for long periods. Squirrels store food in their nests, so they only have to venture out every few days to retrieve food hidden away earlier in the year.
Squirrels will bring in dried leaves and other materials into the nest or den to use as insulation. Squirrels are very serious about building a proper nest because if it is not well insulated, a squirrel can freeze to death. Nests and dens are often shared with other squirrels to benefit from each other’s warm body temperature.
Why Do Squirrels Build Nests in High Trees
Squirrels build nests in high trees to provide protection from predators like foxes and coyotes. Although squirrels prefer to live in dens, which are tree holes sometimes left by woodpeckers or natural causes. Dens provide better shelter than a drey because it provides better protection than a drey against predators and extreme weather conditions. If there is a shortage of nests or dens, squirrels can get highly territorial and fight for their spot in the nest. During warmer months, they usually don’t share nests with other adult squirrels.
What Does A Squirrel Nest Look Like
A squirrel nest, also called a drey, looks a lot like a bird’s nest. A squirrel’s nest is much larger than a bird’s nest. In the wild, nests are built out of branches, twigs, dried leaves, bark strips, mosses, and grasses. Squirrels’ nests sit 20 feet (6 m) or higher. A squirrel chooses a fork or nook of a tree that serves as the foundation. The tree fork serves as a solid and supportive foundation to keep the squirrels safe and secure while sleeping. Squirrels living in urban areas are known to take stuffing to make their nest warm, from items like outdoor furniture cushions, dog beds, and blankets.
Nest building is tedious work. A squirrel gathers materials and piles them all together with its mouth or paws to transport them to the nest. In the wild, nests are built out of branches, twigs, dried leaves, bark strips, mosses, and grasses. Squirrels living in urban areas are known to take stuffing from items like outdoor furniture cushions, dog beds, and blankets.
Building the Nest
First, the squirrel builds the floor by weaving together sticks and twigs. They pay close attention to detail and are sure not to leave any large gaps in the foundation. The inside is lined with materials like shredded bark, grass, moss, and leaves. Damp leaves and moss make the floor soft for the babies.
Like an artist, the squirrel weaves the outer shell in the shape of a sphere. The last step consists of stuffing twigs, moss, and leaves on the outside of the nest. The outer shell has several different layers using a combination of all the building materials used inside the nest. The layers provide stability, and surprisingly the drey is sturdy.
The nest measures about six to eight inches in diameter. Grey squirrels build nests measuring up to 2 feet wide (61 cm). The nest, when completed, resembles a shape similar to a globe.
Where Do Squirrels Go in the Winter: Squirrel Preparation
A Fluffy Fur Coat
All squirrels develop a thicker coat for the winter, and some grow long tufts of ear hair like the Abert and red squirrels. But a rock squirrel has a winter superpower.
The rock squirrel can thermoregulate. One way a rock squirrel can thermoregulate is through its fur coat. During the winter, their coat seems to absorb more solar heat because changes in the wind speed directly affect the squirrel’s coat structure.
Don’t Forget the Snacks
Squirrels store food in their nests, so they only have to venture out every few days to retrieve food hidden away earlier in the year.
North American red squirrels store food in one massive food cache called a midden. The red squirrel will defend its food stash with aggression and violence through the winter.
Grey squirrels have multiple caches of food in case one stash becomes compromised or ruined.
Bring on the Fat
Depending on what area of the world and species, squirrels can add up to 50% fat. To build the fat stores, in the Fall, squirrels consume a mass amount of food.
Sharing is Caring
To keep their core temperatures regulated, they tend to stay close to each other and share a nest or den. Another way to stay warm is to shiver, and shivering generates body heat.
An exciting discovery is that a black squirrel, one version of a melanistic grey squirrel, is more efficient at creating and retaining body heat than other squirrels.
Where Do Squirrels Go in the Winter: Ground Squirrel Hibernation
Ground squirrels hibernate, which lowers the body temperature, slows brain activity, and reduces the heart rate. Not all of the scientific literature agrees on the animal that has the longest and deepest hibernation process. One squirrel is a pro at a very long hibernation, and that is the Arctic Ground Squirrel. The squirrel spends 7-9 months underground in a burrow in deep hibernation.
Their body temperature drops to almost 5 degrees below freezing, an astonishing 26.7 degrees F (2.9 degrees C). This phenomenon, known as supercooling, allows the squirrel’s blood to remain liquid and not freeze. In simple terms, the matter that can freeze or crystalize is filtered from the blood to keep it flowing.
Not All Hibernation is the Same
Again, not all ground squirrels hibernate, but the time and length of hibernation vary for those that do. The California Ground squirrel usually hibernates, but some do not in areas where the winters are not severe.
For instance, the Richardson’s ground squirrel will awake for a few hours at a time during hibernation. When awake, the squirrel raises its body temperature for 1-2 hours. After bringing its body temperature back to normal, the squirrel will immediately drop it again and return to hibernation.
The Risk of Hibernation
Hibernation has its risks. There is a possibility the squirrel’s body temperature drops so low that it may not ever wake up. Take a look at this video of an artic squirrel right after hibernation.
Would You Like To Give Your Squirrels a Home?
If you worry about how your squirrels in the backyard will make it through the winter, you can provide a squirrel family with a nesting box. Take a look at this squirrel home from Back2NatureWood. The house is made of thick, quality pine wood and sealed with an Eco-friendly sealer for durability. Your backyard squirrels will surely appreciate the coziness, warmth, and safety from predators this house provides.
Squirrels are complex animals that are surprisingly able to survive extreme weather conditions.
The winter weather proves challenging, but squirrels survive in many ways, like growing fluffy coats, building up their fat stores, lying dormant, shivering, and hibernating.
Hibernation is fascinating because the squirrel’s body goes through complicated biological changes to slow its heart rate, lower body temperature, and supercool the blood.
Frankly, a squirrel’s ability to survive the winter is exceptionally complex and captivating.
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