What Do Squirrels Do in Winter?

Brrr, it’s getting cold outside! Have you ever wondered how animals like squirrels survive Chicago’s freezing temperatures without so much as a coat? While people typically respond to the cold by staying inside and putting on layers, it turns out squirrels have a similar strategy for dealing with the challenges of winter. They tend to spend more time in the den, and they put on “layers” by fattening up.

The type of squirrel you’re most likely to encounter around Nature Boardwalk at Lincoln Park Zoo is an eastern gray squirrel (Sciurus carolinensis). These are predominantly gray in color—as you would guess from the name—with white bellies.

Gray squirrels do well in urban areas such as Lincoln Park. These critters are homeotherms, which means that unlike some mammals, their body temperatures remain fairly constant throughout the year; they don’t hibernate. In the winter, squirrels spend less time foraging outside their dens, and it’s more common for several squirrels to share a den. This behavior allows more animals to take shelter and also to keep each other warm.

If you’ve been watching the squirrels lately, you may have noticed they’ve been very busy caching food. Caching, also called hoarding, is a behavior characterized by storing stashes of food for later. Squirrels usually do this by putting their food in a shallow hole and covering it up. They don’t remember all these “storage units,” and some of the forgotten seeds they leave behind will germinate and become shrubs, trees, etc. The stashes that are remembered will serve as food when resources are scarce in winter.

Squirrels also prepare for winter by bulking up. Throughout fall, they maximize food consumption and body mass. In winter, when food is hard to come by, these reserves will help the animals survive.

One other tactic gray squirrels use to keep warm in winter is shivering. Shivering isn’t just a sign that you’re cold; it also serves as a way to keep warm. While it certainly doesn’t sound fun, gray squirrels are remarkably good at generating heat by shivering.

The gray squirrels at Nature Boardwalk are busily eating everything in sight and storing food for later. Come down to Nature Boardwalk today to see them in action as they gear up for the approaching cold and snow!

Vicky Hunt


Thank you for this info. Recently a huge nest fell out of our tree and I keep waiting to see if the squirrels will rebuild, but so far they have not.

I recently put a small white pumpkin outside on my deck to see what would happen to it and the squirrels have been eating it. It's fun to watch them.

great answers

cool I love to know this

cool I love to know this

Thanks for the Comment

Glad you enjoyed it!

what is a typical life span

what is a typical life span for these squirrels?

Great Question

The earliest part of life is the most hazardous time for most mammals, so the median life expectancy for a newborn eastern gray squirrel is 1-2 years. If the squirrel reaches adulthood, however, the median life expectancy is roughly 6 years.

We have a small vineyard and

We have a small vineyard and for the first time the squirrels are putting black walnuts about five feet up in the vines. What could this possibly mean? Lots of snow this year?

squirrels tails

I heard that a squirrels tails get thicker and they have their nests up higher in the trees, when we are going to get a bad winter. Is this true? How can they detect a the weather?

Interesting Question

We shared that with our ecological analyst, Mason Fidino, and he says, "I have never heard that before. Squirrels do fatten up when it starts getting colder outside, which does have clear benefits to surviving the winter, but I cannot think of a single reason that nesting higher in a tree would positively benefit a squirrel. As to how they detect weather, it is very similar to the rest of us. When it starts getting consistently colder, and day lengths begin to shorten, the species starts acting differently (storing food, fattening up, getting a little fuzzier, etc.). I am going to go out on a limb here and guess that this is not truly the case. An interesting idea to test though!"

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