Squirrels are busy animals. When it is nice outside, it is hard to go anywhere or spend more than a minute looking out your window without seeing a squirrel. While these animals are busy throughout the warmer months, I started to wonder about how they got through the winter.
More specifically I wondered, “Do grey squirrels hibernate?” I did some research and found that the answer is:
Grey squirrels do not hibernate. Grey squirrels use multiple mechanisms to survive the cold including group warmth, shivering, food caching and bulking up for winter.
Grey Squirrels Do Not Hibernate
It turns out that grey squirrels are warm-blooded homeotherms. Homeotherms maintain a constant body temperature throughout the seasons so hibernation is not necessary.
The primary mechanisms grey squirrels employ for winter survival include:
- Building protected nests
- Sharing body heat
- Reducing physical activity
- Creation of food caches
- Development of fat stores
- Development of a thicker coat
- Utilization of shivering
Grey Squirrels Build and Share Protected Nests
Grey squirrels make it through the winter by building warm nests or dreys.
Most tree squirrels will share their nests with other squirrels for the benefit of the shared body heat. Grey squirrels will share a nest with just a few other squirrels while Flying squirrels have been known to share a nest with more than 20 other squirrels.
Here is a peek inside a grey squirrel nest…it looks kind of cozy in there!
Grey Squirrels Reduce Physical Activity in Winter
Once the squirrels are in their nests they tend to stay there as much as possible. Grey squirrels will often stay in their nests for 2-3 days at a time and only come out to search for food around midday (source).
By staying in their nests they use less energy, stay warmer and help maintain the shared body heat.
Grey squirrels spend much of the fall preparing food stores for winter. Squirrels stash away acorns, hickory nuts, walnuts, etc for winter munching. This is called scatter hoarding.
(Read more here: What Do Squirrels Eat? Two Big Surprises!)
Grey squirrels are classic scatter hoarders which means that they make as many food stores as possible. This behavior is a form of food protection so if one or two food sources get discovered by other squirrels they still have plenty of other food sources in reserve.
One benefit of the grey squirrel’s rampant nut caching behavior is that it is impossible for the squirrel to remember where all of the nuts are buried. Many of the undisturbed buried nuts will germinate, sprout and turn into the next generation of forest trees.
The instinctual drive to hide food gets somewhat comical at times. Squirrels will hide nuts in car engines, in the fur of sleeping dogs and in the pockets of people who just gave them a nut! If you would like to check out some silly videos of squirrels and their silly food caches then check out this article on Where Do Squirrels Hide Their Nuts?
Grey Squirrels Bulk Up with Fat and a Thicker Fur Coat
In the fall, when tree nuts are plentiful, squirrels will eat voracious amounts of extra food to pack on weight and develop an increased fat layer. Some estimates say that the grey squirrels consumes 32% more food than energetically required during the fall and increase their weight by 25%. (source)
The increased fat layer serves as a layer of insulation to protect the squirrels core body temperature as well as a reserve of energy for when food sources become scarce.
They also rely on their fat reserves to survive the long, cold winters. (source)
In addition to gaining weight, squirrels adapt their bodies for winter by developing a thicker coat. In colder regions the thicker coat is expanded to include more fur on their ears and the soles of their feet (source).
Grey Squirrels Shiver for Warmth
Grey squirrels utilize shivering to generate extra body heat during cold winter months.
An interesting study has found that black squirrels, which are genetic variations of grey squirrels, are better at shivering and may eventually become dominant species in colder climates.
How You Can Help Grey Squirrels Survive Winter
If you want to help your squirrels make it through winter then there are several things you can do by providing:
- Nesting material
How to Provide Shelter For Grey Squirrels
While squirrels will share nests to stay warm there is not always room for everyone. The availability of prime nesting sites is one of the factors that determine whether a squirrel will make it through the winter.
There are several squirrel houses for sale that you could put up in your backyard that would provide much needed and appreciated shelter.
Provide Nesting Material
Squirrels line their nests with leaves, twigs and other debris to form an insulating barrier.
You can provide a supply of nesting material that has even better thermal properties than leaves and the squirrels will use it to make their nest extra warm. According to The Squirrel Board Forum some great choices for nesting material include:
Anything with rope like fibers (yarn, etc) should be avoided as baby squirrels can get tangled in the threads.
Provide Food and Water for Squirrels During the Winter
Squirrels need to eat and drink during the winter so a readily accessible source of food and water will help them greatly.
Here is a great article on What to Feed Wild Squirrels if you need ideas on what to put in a feeder.
A heated water bath would also be nice providing that it can be placed in close proximity to the tree where the squirrels are nesting. You do NOT want to make the squirrels travel far from their nest for either food or water. Squirrels are ruthlessly hunted by hawks and in the winter time the protective coverage of tree leaves is absent.