When someone mentions “squirrel,” many think of the pests that attack our bird feeders in spring and summer. Then, during the fall, they busily skitter around collecting and burying nuts before they, mercifully, disappear during the winter. But have you ever wondered why do squirrels bury nuts in the first place?
Squirrels bury nuts and seeds to create a food stockpile for the winter season. This stockpile results in food being available during periods when it may otherwise be unobtainable. Furthermore, by burying nuts and seeds, squirrels hide food from opportunistic competitors.
With the buzz of activity that squirrels bring during their stockpiling, a few more questions come to mind, like, are there particular nuts and seeds they prefer? Do all squirrels bury nuts? And, once buried, how often do squirrels find these nuts?
Squirrels and Their Nuts, The Reasons for Their Storing Habits
Squirrels are mammals found across the globe, on every continent except for Australia and Antarctica.
Belonging to the Sciuridae family, over 200 species of squirrels are grouped into three over-arching categories. Namely, ground squirrels, flying squirrels, and tree squirrels.
Squirrels are well adapted to the environments that they find themselves in.
Some squirrels have big bushy tails to shade themselves/keep themselves warm, while others are better suited to an arboreal or montane lifestyle.
Squirrels Diets and How Nuts Fit into the Picture
Squirrels are omnivores (they eat nuts and seeds, other plant parts, insects, and even small eggs), and their feeding habits are based on where they occur.
In the northern hemisphere (and other colder regions in general), most squirrel species collect food for the winter. This food includes nuts and seeds from various trees.
The quintessence for this behavior is linked to the seasons.
In the colder temperature regions of the world, many animals (mammals, insects, and reptiles) enter a prolonged period of sleep known as hibernation.
Some animals don’t undergo a true hibernation, but only a form of hibernation, or at the least slow down their activities during the winter season.
Building up to winter, many animals (squirrels included) collect food that won’t perish too quickly and store it to have food to eat during the winter.
Although squirrels don’t hibernate, they do hunker down for the winter frost in their nests, limiting their movements and activities to the bare necessities, visiting food caches.
They outlast the cold by metabolizing stored fat and eating what was stored in their stockpiles/larders. These pantries generally hold enough food to last all of winter and longer.
When spring returns, plants and insects do not immediately emerge; this means that squirrels would still have a food source to tide them over.
Some squirrels don’t hide all their food in one place but rather “scatter hoard” in smaller caches distributed over their home range (an area of up to around seven acres).
Other squirrels, however, create one stockpile (referred to as a midden) and aggressively defend it from competitor squirrels and other opportunists.
Squirrels don’t limit their stockpiling to nuts and seeds. They also bury insects, berries, and even bones.
Another reason for hiding food by burying it is to avoid competition, both from other squirrels (the same and different species) and other animals.
Since squirrels remember where they hid their caches (and that many species bury numerous scattered stores), food is hidden from anyone who did not do the hiding.
Examples of Nuts and Seeds Frequently Buried By Squirrels
Which nuts and seeds will depend significantly upon the area in question, however commonly buried and fed upon species include:
- Oaks
- Walnuts
- Beeches
- Hazels
- Horse chestnuts
- Alders
- Aspens
- Birchs
- Cypress
- Field Maples
- Hawthorns
- Hollys
- Junipers
- Poplars
- Western Hemlocks
- Western Red Cedars
- Willows
Which Squirrels Bury Nuts, and Why Don’t Others?
Not all squirrels bury nuts and seeds. Some species live in areas where the winter is mild, with little to no frost, and therefore do not need to store up food as it is readily available all year.
Squirrels that hoard use various hiding places when creating their caches, including tree cavities, forks in branches or tree stems, under a pile of leaves, fallen logs, and a hole in the ground.
Below are some examples of squirrels that bury food for use during the winter period.
Squirrels of North America That Bury Nuts
We have put together a list of North American squirrels that bury nuts for when they need them.
- American Red Squirrels (Tamiasciurus hudsonicus) bury their nuts/seeds in single middens.
- Douglas Squirrels (Tamiasciurus douglasii) bury their nuts/seeds in single middens (larder-hoarding).
- Eastern Grey Squirrels (Sciurus carolinensis) bury their nuts/seeds in scattered caches.
- Fox Squirrels (Sciurus niger) bury their nuts/seeds in scattered caches.
Squirrels That Don’t Bury Nuts
Although limited, a few species of squirrels do not habitually bury food for the winter period, which is mainly due to sufficient winter feeding.
- Abert’s Squirrels (Sciurus aberti) feed off of Ponderosa Pines, among other species. They eat pine cones and buds during the summer, while they eat tree bark in the winter.
- Cape Ground Squirrels (Geosciurus inauris) live in South Africa, in areas where they can forage throughout the year and do not need to hoard food in a burrow.
- Northern Flying Squirrels (Glaucomys sabrinus) have a diet that centers on fungi and lichens. They are active throughout the year and therefore do not stockpile food.
How Do Squirrels Find the Food They Bury?
Scientists are discovering increasingly astounding facts about how squirrels can find their hidden caches during and after the winter.
With regards to scattered cache squirrels:
Originally it was believed that squirrels located their buried food by scent; however, with snow covering the ground, this seems impractical (although scent does play a role).
Researchers, in recent studies, determined that squirrels have a “mental map” of their area and caches, called “spatial chunking.” Often the use of landmarks is pivotal to this process.
By using this memory map, squirrels can remember where they buried their caches. Coupled with a great sense of smell, they can find their food (most of the time) when needed.
Scientists further discovered that squirrels bury similar nuts in a designated area while other nuts were grouped in other locations. The reason for this is to help them remember where the various caches are hidden.
Squirrels tend to dig up and re-bury caches, which helps them remember where they buried what and make sure the food is still okay.
Researchers have even determined that squirrels (particularly the Eastern grey and fox) hide some of the higher “value” nuts/seeds in more vulnerable, exposed areas.
This choice of hiding place would be to discourage competitors from looting their caches because of the increased risk of predation.
In 2008 a study that Michael A. Steele, from Wilkes University, was part of discovered that squirrels pretend to bury food in one place to mislead competitors.
If theft is a severe problem, squirrels also get creative in their hiding spots to deter would-be looters as much as possible.
By remembering which cache had what type of food and the size of each, squirrels opt to return to the most substantial, high-quality stockpiles first.
An Important Consequence of Squirrels Nut Burying Habits
Although squirrels bury nuts and seeds for their own survival purposes, there is an additional benefit in the whole process, namely, forestation.
Squirrels don’t always retrieve/recover all of their nuts buried. When these seeds/nuts are buried in the ground, they begin to germinate.
These seedlings grow and develop into the next generation of trees. Grey squirrels, in particular, are believed to be fundamental in this seed dispersal process.
Final Thoughts
Although not all species of squirrels bury nuts, those that do place the collected food in either a single midden larder or in various, diminutive, scattered caches. Squirrels that bury nuts generally live in colder areas with harsh winters and do so to survive the frost and food scarcity.
Ben has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies, you can find him at home with wife and two daughters. Outside of family, He loves grilling and barbequing on his Big Green Egg and Blackstone Griddle, as well as working on projects around the house.
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