Do Squirrels Hibernate?
The Surprising Truth About Winter

Every November, the squirrels on our 30-acre property in Michigan seem to vanish. The feeders go quiet, the oak trees stop rattling with activity, and for weeks at a time the woods feel empty. But they haven't gone anywhere — and they certainly haven't hibernated. What they're doing is far more interesting than sleeping.

Do squirrels hibernate?

The short answer: it depends on the species. Most squirrels — including the gray, fox, red, and black squirrels you see every day — do not hibernate. Ground squirrels are the major exception, entering one of the deepest and most dramatic hibernation states of any North American mammal.

This surprises most people because squirrels do seem to disappear in winter. But what's really happening is a combination of reduced activity, food caching, and a state called torpor — which is distinctly different from true hibernation. Understanding the difference changes everything about how you think about squirrels in winter.

Hibernation vs. torpor — what's the difference?

This is the most misunderstood part of the whole conversation. Hibernation and torpor are not the same thing, and most squirrels only do the latter.

Think of it this way: hibernation is a months-long shutdown. Torpor is hitting the snooze button for a day. Tree squirrels like gray squirrels, fox squirrels, and black squirrels use torpor to ride out the coldest days, then wake up and head out to retrieve cached food when temperatures rise.

Do squirrels hibernate in the winter?

Tree squirrels do not hibernate in winter in any true biological sense. What looks like hibernation to most people — weeks of squirrel absence, quiet feeders, still trees — is actually a combination of reduced activity, torpor during cold snaps, and strategic stays in the nest on the coldest days.

When temperatures drop below 30°F, gray and fox squirrels can spend several consecutive days in their dreys without venturing out. Their heart rate and metabolism slow slightly, and they rely on nearby cached food stores when they do emerge. On warmer winter days — especially anything above 40°F — you'll see them back out foraging as if it were October.

Do gray squirrels hibernate?

No. Eastern gray squirrels are homeotherms — their body temperature stays relatively constant year-round. They are physically incapable of true hibernation. What they do instead is remarkable in its own right: they spend the entire autumn in a frenzied campaign of scatter hoarding, burying thousands of individual food caches across their territory.

Research has shown gray squirrels retrieve their caches using a combination of spatial memory and smell — and that they intentionally deceive other squirrels by pretending to bury food in fake locations when they know they're being watched. In winter, this network of hidden food keeps them alive between cold snaps when they emerge from their nests on warmer days.

Do fox squirrels hibernate?

No. Fox squirrels — the large, rusty-orange squirrels common across the Midwest and Michigan — do not hibernate. Like gray squirrels, they rely on scatter hoarding and torpor to survive winter. Fox squirrels tend to be more active in winter than gray squirrels, often venturing out even on days when temperatures remain well below freezing.

Fox squirrels are also more solitary than gray squirrels. While grays will sometimes share a nest in extreme cold, fox squirrels typically tough it out alone — relying on their larger body mass to retain heat more efficiently.

Do red squirrels hibernate?

No. Red squirrels — the smaller, feisty species found in northern forests — are actually one of the most winter-active squirrels of all. Rather than scatter hoarding like gray and fox squirrels, red squirrels practice larder hoarding: they create one massive, centralized food cache called a midden, which they defend aggressively year-round.

Because their food is always close by and well-stocked, red squirrels have no need to enter torpor and are frequently spotted in Michigan winters foraging and defending their territory even in heavy snow.

Do black squirrels hibernate?

No. Black squirrels are not a separate species — they are a melanistic color variant of the Eastern gray squirrel. Their winter behavior is identical to gray squirrels: torpor during extreme cold, scatter hoarding, and nest sharing for warmth. The black coloration may actually provide a slight advantage in winter, as darker fur absorbs sunlight more efficiently and may help maintain body temperature on cold clear days.

Do flying squirrels hibernate?

Flying squirrels don't truly hibernate, but they come closer than any other tree squirrel. During extreme cold, flying squirrels enter extended group torpor — clustering together in large communal nests of 10 to 20 individuals, sharing body heat and significantly reducing their metabolic rate. These torpor episodes can last several days at a time.

Flying squirrels are nocturnal, so most people never see them — but they're remarkably common across Michigan's hardwood forests. If you have old trees with cavities on your property, there's a good chance flying squirrels are using them as winter communal roosts right now.

Do ground squirrels hibernate?

Yes — and dramatically so. Ground squirrels are true hibernators, entering one of the most extreme metabolic states of any warm-blooded animal. The 13-lined ground squirrel common across Michigan and the Midwest can hibernate for up to 8 months, with its heart rate dropping from 200 beats per minute to just 5, body temperature falling to within a degree of the surrounding soil, and breathing slowing to just one breath per minute.

Arctic ground squirrels take this even further — their body temperature can drop to 27°F, technically below freezing, making them the only warm-blooded animals known to survive supercooling.

When do squirrels hibernate?

For the ground squirrels that do hibernate, timing varies by species and location. The 13-lined ground squirrel in Michigan typically enters hibernation in October and emerges in late March or early April — roughly 5 to 6 months. In northern populations and higher altitudes, hibernation periods can stretch closer to 8 months.

Tree squirrels don't have a defined hibernation window because they don't hibernate. Their activity simply decreases in proportion to temperature and food availability. The coldest weeks of January and February see the least activity — sometimes days go by without a gray squirrel leaving its nest.

Where do squirrels hibernate?

Ground squirrels hibernate in underground burrows, often 3 to 6 feet below the surface where temperatures stay stable. They seal the entrance from inside and enter their torpor chamber — a carefully constructed nest of grass and leaves.

Tree squirrels don't hibernate, but they do spend extended cold periods in their dreys — the round leaf-and-twig nests visible high in deciduous trees in winter — or in tree cavities, which offer better insulation. On our property in Michigan, the squirrels strongly prefer cavity dens in large old oaks when winter temperatures drop below 20°F.

What do squirrels do in winter instead of hibernating?

Tree squirrels survive winter through four main strategies working together:

1. Scatter Hoarding

Starting in late summer, gray and fox squirrels bury thousands of individual food caches — acorns, hickory nuts, walnuts, and seeds — in shallow holes across their territory. A single gray squirrel may create up to 10,000 caches in a single season. These distributed food stores are the foundation of their winter survival strategy.

2. Fat Reserves

Squirrels eat aggressively in fall to build up fat reserves. This extra body fat serves as both an energy source and insulation during cold snaps when they stay in the nest for days at a time.

3. Nest Sharing

While tree squirrels are typically solitary, they'll share a drey with other squirrels during severe cold to conserve heat. Multiple squirrels huddled together in a well-insulated nest can maintain warmth even when outside temperatures drop well below zero.

4. Torpor During Cold Snaps

On the coldest days, tree squirrels reduce their metabolic rate, lower their body temperature slightly, and simply wait it out. Unlike true hibernation this can last hours to a day — and the squirrel wakes fully once temperatures rise and ventures out to recover cached food.

The Great Squirrel Migration of 1968

How to help squirrels survive winter on your land

On private land, there are several things you can do to support squirrels through the hardest winter months. We do all of these on our 30-acre property in Michigan and the difference in winter squirrel activity is noticeable.

Supplemental feeding and heated water sources make a measurable difference during the coldest weeks of January and February:

📖 The Story Behind This Land

The squirrels on our Michigan property live in the same oak corridor that Billy Gruett — a 16-year-old Chippewa mail carrier — rode through every week in the 1850s. His story inspired our wildlife habitat mission.

Read His Story Free eBook →

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