Ever watched a squirrel dart across a snowy yard and wondered where it disappeared to? Most tree squirrels don’t actually hibernate—they just sleep more in their nests, while many ground squirrels really do hibernate in underground burrows for months.
Let’s get into which squirrels tuck away for the winter, which ones just nap in leafy nests, and why all these choices matter for their survival. I’ll break down what hibernation means for squirrels, where they hide out, and how they manage to stay warm and fed through the worst of winter.
Keep your eyes open for signs of squirrel activity near your home. There are even some simple ways you can spot or help them this winter as you read on.
Where Do Squirrels Hibernate?
Squirrels pick shelters based on their species and the local climate. Some spend months sleeping deep underground, while others curl up in tree nests, cavities, or—if they’re bold—your attic.
Tree Squirrels: Nests and Dens
Tree squirrels like eastern gray squirrels and fox squirrels usually stick around in nests called dreys or in tree cavities. Dreys are rough, leafy homes made from twigs and moss, tucked into forked branches.
They pack these nests with softer stuff like shredded bark. It’s not fancy, but it works.
Tree squirrels don’t go into deep hibernation. They just take short naps—torpor—on really cold nights and stay curled up inside their drey or cavity.
When the weather’s mild, you’ll see them out digging up buried nuts from their scatter-hoarding sites.
If a cavity is available, squirrels usually pick it because it keeps out wind, rain, and predators. You might spot activity at a hollow high in a mature tree in the fall, when they’re prepping for winter.
Ground Squirrels: Burrows and Underground Chambers
Ground squirrels—think California ground squirrel, Richardson’s ground squirrel, or the Arctic ground squirrel—hibernate in burrow systems. These burrows have sleeping chambers lined with grass, hair, or plant matter, and even extra nooks for food or waste.
Ground squirrels really do hibernate. Their body temperature and heart rate drop way down, and they stay underground for months.
You won’t see them above ground at all during most of the winter.
Burrow systems have multiple entrances for air and quick escapes. The depth and design change depending on the soil and climate.
Arctic ground squirrels dig especially deep, trying to avoid freezing solid.
Flying Squirrels: Communal Nesting
Flying squirrels are nocturnal, and they don’t hibernate like ground squirrels. Instead, they use tree cavities and nests, often sharing with others.
Communal nesting means as many as 20 flying squirrels might pile in together, sharing body heat when it’s cold.
You’ll find their nests inside tree cavities, behind loose bark, or in old woodpecker holes. They line these spots with soft material to keep everyone warm.
Because flying squirrels are active at night, you almost never see them during the day. If you peek into the right tree cavity in winter, you might spot signs of several squirrels and lots of cozy nest lining.
Urban Hideouts: Attics and Buildings
In cities and towns, squirrels get creative. They sneak into attics, wall spaces, and eaves.
Eastern gray squirrels and fox squirrels often find their way in through gaps in roofs or soffits. Once inside, they build nests out of leaves, twigs, insulation—whatever’s handy.
If squirrels move in, you’ll probably hear scratching, scurrying, or find droppings in the attic. Attic nests offer steady warmth and protection, so squirrels will fight to keep these spots in winter.
If you suspect squirrels are inside, look for entry holes, torn shingles, or chewed vents. It’s best to seal up openings after they leave in spring to keep them from coming back.
How Squirrels Survive Winter
Squirrels use a few clever tricks to get through winter. Some hibernate for real, while others just slow down and rely on fat, hidden food, and sturdy nests.
You’ll notice changes in where they sleep, how often they move, and even how their bodies save energy.
Winter Hibernation Versus Dormancy and Torpor
Some ground squirrels are true hibernators. They enter deep hibernation—metabolic rate, heart rate, and breathing all drop for weeks.
If you find a ground squirrel underground in winter, it’s probably in that deep sleep until spring warmth wakes it up.
Tree squirrels (gray, red, fox) don’t do that. Instead, they use short bouts of torpor—brief drops in activity and body temperature that last hours or maybe a couple of days.
They might also stay tucked in their nests for days between foraging trips.
This explains why you can spot tree squirrels in winter—they’re out looking for cached nuts and acorns. True hibernators stay hidden in burrows, dodging predators and bitter cold.
Fat Reserves and Stored Food
Watch squirrels in fall and you’ll see them eating nonstop. They chow down on seeds, nuts, berries, and even birdseed to build up fat reserves.
Some species pack on 25–50% more body weight, which helps them survive long stretches without food.
Most tree squirrels scatter hoard—they bury lots of small caches of nuts and acorns all over their territory. You’ll spot them digging and covering spots again and again.
Stored food means they don’t have to risk moving around in nasty weather, which also helps them avoid predators. When things get desperate, squirrels might even raid each other’s caches or strip bark to find calories.
Nesting Materials and Insulation
Squirrels pick or build insulated nests—dreys—in tree branches, or they use cavities, attics, or burrows. They stuff these nests with leaves, moss, feathers, and grass to trap heat.
Sometimes, more than one squirrel shares a cavity to stay warmer together. In snowy places, nests might be deeper or tucked somewhere less windy.
Good insulation keeps their body temperature steadier, so they need less food and can spend more time resting, even when it’s icy and cold outside.
Physiological Changes: Heart Rate and Body Temperature
When squirrels go into torpor or hibernation, their heart rate and breathing slow down a lot. They can drop their heart rate from pretty high resting levels to just a tiny fraction of normal.
Breathing turns slow and shallow, almost like they’re barely there. Their body temperature falls too, but it really depends on the species.
True hibernators let their body temperature get close to whatever the air is, which sounds risky, right? Tree squirrels don’t go that far—they keep it higher and only let it drop a bit.
These changes help them save energy, so their fat and stored food last longer. You almost never catch a hibernating squirrel moving.
They only wake up to eat from their stash or to warm themselves if things get too cold.
- Squirrels forage and recover their caches during warmer spells.
- Predators still lurk near nests and burrows, so having a hidden, quiet shelter really matters.
- Snow insulates burrows but makes it tough to find food above ground.
If you’re curious about how tree squirrels handle winter without hibernating, check out this overview of winter squirrel behavior. (https://www.backyardpests.com/do-squirrels-hibernate/)
