Most squirrels sleep in nests they build in trees, either leafy structures wedged into high branches or hollowed-out cavities in trunks. The exact sleeping spot depends on the species, the season, and what’s available. Tree squirrels, ground squirrels, and flying squirrels all take different approaches, but they share a common priority: finding shelter that’s warm, dry, and hard for predators to reach.
Tree Squirrels and the Two Types of Nests
Tree squirrels like the eastern gray squirrel rely on two main sleeping spots: leaf nests (called dreys) and tree cavities (called dens). Dreys are the messy balls of leaves and sticks you’ve probably noticed in bare winter trees. They’re typically a foot or two wide, built near the trunk or in the fork of two strong branches for stability. The outer layer is woven from leafy branches, while the inside is lined with softer material like moss, pine needles, and shredded bark. Squirrels enter through a small hole that faces the trunk, which helps block wind and hide the entrance from predators.
Tree cavities are the preferred option when available, especially in cold weather. Eastern gray squirrels use dreys during summer but shift to cavities for winter, where the thick wood walls provide far better insulation. These natural hollows form when branches break off and the wood decays inward, or when woodpeckers excavate holes that squirrels later claim. Female squirrels also strongly prefer cavities when raising young, since the enclosed space is safer and more temperature-stable than an exposed leaf nest.
Red squirrels follow a similar pattern but tend to build their dreys in coniferous trees like pines and spruces, close to their preferred food source of pinecones. Some red squirrels also build ground-level nests under logs buried in deep snow during winter, giving them easy access to food they’ve cached nearby.
How High Up Squirrels Build
Squirrel nests sit surprisingly high. A study tracking over 140 dreys found that 60% were positioned between 40 and 60 feet above the ground, and the vast majority were placed in the top fifth of the tree’s total height. Only a handful of nests sat below 30 feet. About 28% were built right at the treetop, with another 32% just a few feet below it. The rest were positioned against the main trunk or a few feet out along a sturdy, upward-angled branch.
This height isn’t random. Building high keeps squirrels above most climbing predators and makes it harder for hawks and owls to swoop in through dense upper branches. The trade-off is wind exposure, which is why squirrels tuck their nests close to the trunk or into branch forks where the structure is most stable.
Ground Squirrels Sleep Underground
Ground squirrels take a completely different approach, sleeping in burrow systems they dig into the earth. These tunnels start with an entrance about four inches wide and extend anywhere from 5 to 30 feet in total length. Most burrow systems stay within two to three feet of the surface, though some reach six feet deep or more. The layout ranges from a single straight tunnel to a complex branching network with multiple entrances and chambers.
The sleeping chamber sits at the end of a tunnel, lined with grass and other dry material for insulation. When ground squirrels enter a period of dormancy during the hottest part of summer (a behavior called estivation), they plug the tunnel near their nest with soil while leaving the entrance looking open. This creates a sealed, climate-controlled pocket underground. They do the same during winter hibernation, blocking off their sleeping chamber to maintain stable temperatures while the surface freezes above them.
Flying Squirrels Prefer Cavities
Northern and southern flying squirrels are nocturnal, sleeping through the day in tree cavities whenever they can find them. U.S. Forest Service research found that two-thirds of all flying squirrel dens were located in live trees, with the rest in dead standing trees, stumps, and even cavities in the branches of fallen trees. When cavities are scarce, flying squirrels will sleep in dreys, sometimes repurposing abandoned bird nests or nests built by other squirrel species.
Flying squirrels are notably social sleepers. Multiple adults regularly share the same den, and denning partners shift depending on which cavity is being used. The one exception is maternal dens, where females give birth and nurse young. Those are occupied by a single mother and her litter.
Sharing Nests in Cold Weather
Squirrels that are normally territorial will share sleeping quarters when temperatures drop. Research on red squirrels found that nearly one in five females engaged in communal nesting during late winter and early spring, typically in groups of two or three. This happened more often on the coldest nights, and the benefit is straightforward: huddling together reduces the amount of body surface exposed to cold air and warms the space around the group. This cuts the energy each squirrel needs to spend on staying warm, which matters when food is limited and winter fat reserves are dwindling.
Gray squirrels show similar behavior. Groups of three to six may pile into a single tree cavity on frigid nights, sharing body heat in a space that’s already well-insulated by the surrounding wood.
Squirrels in Attics and Buildings
In urban and suburban areas, squirrels sometimes swap tree cavities for attics, chimneys, soffits, and wall voids. From a squirrel’s perspective, an attic is just a large, dry, predator-free cavity with excellent insulation already installed. Mother squirrels are especially drawn to these spaces when looking for a safe place to give birth. Once inside, they’ll tear apart existing insulation or bring in nesting material from outside to build a sleeping nest, leaving behind droppings and urine that create odor and potential health concerns.
Squirrels typically enter through gaps where roof lines meet, uncapped chimneys, or damaged vents. If you hear scratching or scurrying in your attic during early morning hours, a squirrel nest is one of the more likely explanations.
How Much Squirrels Actually Sleep
Wherever they bed down, squirrels spend a lot of time there. Tree squirrels sleep roughly 15 hours per day, or about 62% of every 24-hour cycle. Most of that sleep happens at night for diurnal species like gray and red squirrels, which are active during morning and late afternoon and return to their nests well before dark. Flying squirrels flip that schedule entirely, sleeping through daylight hours and foraging at night.
Squirrels don’t sleep in one long stretch the way humans do. They cycle between rest and brief periods of wakefulness, occasionally shifting position or checking for threats. During winter, tree squirrels may stay in their nests for several days at a time during extreme cold, venturing out only to retrieve cached food before retreating back to sleep.