Ever wondered where squirrels disappear to on those cold, silent days? Most tree squirrels don’t actually hibernate. Instead, they stash food all over, slip into torpor for quick energy savings, and hunker down in their nests.
If you know this, you can spot them on milder winter days—and you’ll understand why they seem to vanish when a storm rolls through.
Most squirrels stay active through winter, while only a few ground species truly hibernate. Up ahead, I’ll break down how food caching, torpor, and those cozy dreys help squirrels survive the cold months.
Oh, and ground squirrels? They’re the main hibernators in the bunch.
Why Squirrels Don’t Hibernate
Squirrels get through cold weather with a mix of quick rests, food stashes, and warm nests. They don’t really hibernate the way some animals do.
Let’s dig into how actual hibernation compares to the short-term torpor squirrels use, and how these habits change across species.
Understanding Hibernation Versus Torpor
Hibernation is a deep, drawn-out sleep. Body temperature, heart rate, and metabolism all drop for weeks or even months. Some ground squirrels pull this off, living off their fat reserves without eating or drinking.
Torpor is different—it’s shorter and reversible. Tree squirrels use it for hours or maybe a day or two when it gets really cold.
Think of torpor as a quick power-saving mode. Squirrels can wake up fast, grab a snack from their cache, or bolt if there’s danger.
When you know the difference, it makes sense why backyard squirrels show up on some winter days. True hibernators are gone for months, but torpid tree squirrels still need to eat and move around when it warms up a bit.
Tree Squirrels and Winter Survival Tactics
Tree squirrels like eastern grays and fox squirrels don’t hibernate for long stretches. You might see them less often, but they stay active on warmer days, digging up nuts they hid earlier.
They build dreys—those messy-looking leaf nests—or use tree hollows to keep out the cold.
In fall, squirrels go wild, hiding thousands of nuts or, if they’re American red squirrels, building a single big midden. Those stashes keep them fed when it’s freezing outside.
On the coldest nights, they slip into torpor to save energy. When the sun comes out or things warm up, they wake and eat.
If you want to help, leave some natural cover, fresh water, and plant native trees that drop nuts. It makes life easier for squirrels, and they won’t need to rely on hibernation.
Common Types of Squirrels and Their Habits
Each squirrel species has its own winter strategy. Eastern gray and fox squirrels scatter-hoard nuts and use dreys for shelter. They use memory and smell to find their buried snacks all winter.
American red squirrels go for a central cache or midden and fiercely defend it. Flying squirrels? They’re night owls and often huddle together in tree hollows to share body heat.
Ground squirrels are the real hibernators here. Some drop their body temperature nearly to freezing for months on end.
If you catch a squirrel out and about in winter, it’s probably a tree or flying squirrel foraging or moving between nests. You’re not seeing a hibernator waking up.
Want to dig deeper into squirrel survival? Check out this article on how some squirrels make it through the longest, coldest periods: Science.org: How Hibernating Squirrels Survive Months Without Water.
Ground Squirrels: The Hibernation Exception
Ground squirrels are a mixed bag—some hibernate for real, while others stay busy most of the year.
Let’s look at which species actually hibernate, how to spot it, and how these ground dwellers handle winter differently than tree squirrels.
Which Ground Squirrels Truly Hibernate
Many true hibernators live underground. The 13-lined ground squirrel and a few other prairie and alpine species drop their heart rate, body temperature, and metabolism for months.
They sleep in burrows that keep them safe and warm, away from predators and the worst of the cold.
But not every ground squirrel does this. California ground squirrels, for example, often stay active if winters are mild—especially along the coast or at low elevations.
Move up to higher elevations in California, and those same squirrels might hibernate if the winter drags on and gets cold enough.
If you’re checking out a local group, pay attention to latitude and elevation. Northern or high-elevation squirrels almost always hibernate.
Down in urban, temperate, or Mediterranean areas, they usually stay active all year.
Telltale Signs of Hibernating Animals
You can spot a hibernating ground squirrel by some clear signs. In late summer and early fall, they bulk up, packing on fat for energy.
Their burrow entrances might be sealed off or lined with extra insulation.
When they’re in deep hibernation, you won’t see any activity for weeks or months. If they wake up, it’s usually just to drink or shift positions before slipping back into torpor.
Scientists track hibernation by measuring low body temperatures and slow breathing.
Another clue? Predator avoidance. Some ground squirrels start hibernating earlier in areas with lots of predators.
If you’re using cameras or motion sensors on burrows, long stretches of no activity in winter pretty much mean true hibernation—not just a quick nap.
Comparing Ground and Tree Squirrel Winter Strategies
Tree squirrels and flying squirrels take a different route when winter hits. You’ll usually spot them tucked away in dreys or tree cavities, sleeping more than usual, but they don’t really let their body temperature drop much.
They count on food they’ve stashed away and take frequent, short naps—what scientists call torpor—instead of diving into months-long hibernation.
Ground squirrels, on the other hand, go all-in on deep hibernation if the winter drags on and food runs low. They build up fat and hide out in well-insulated burrows. Sometimes, they manage to go for months without eating or drinking.
Tree squirrels wake up often to snack from their caches, which is a pretty big difference compared to their ground-dwelling cousins.
If you’re trying to figure out what a squirrel will do, you should look at its species and where it lives. Ground squirrels usually hibernate in colder, open places. Tree squirrels just slow down if food gets scarce, but you won’t see them truly hibernate.
Want to get into the details—like which species hibernate or how they handle water and waking up? Check out this article on how hibernating squirrels live for months without water.
