Squirrels are famous as hoarders of acorns and other nuts. As the squirrel food pyramid indicates, nuts and other plant-based foods make up the bulk of their diets. Since squirrels are active year round, they need to store up food ahead of time to sustain themselves through the winter. Nuts make a great storage food because they can keep for months on end. Most of a squirrel’s winter nut caches are collected and buried in the ground during the months of September and October.1
Nuts About Nuts
Each year, a single squirrel may bury thousands of nuts.2 That’s a lot of food that will later need to be retrieved! Moreover, squirrels can spread their nut caches across an area larger than two square miles, and it may be up to 9 months before they need to return and dig up these stashes.2 So how do squirrels manage to find all these nuts?
Memory, Smell… or Both?
In fact, squirrels don’t recover all the nuts that they bury. They only need to find enough to survive the winter. Squirrels use a combination of memory and smell to relocate buried nuts.2 They’re able to remember the general whereabouts of their caches, and when they’re close enough to where a nut is buried, they can then sniff out its exact location. Interestingly, squirrels will sometimes dig up some of their nuts only to rebury them somewhere else.2
DID YOU KNOW…
Squirrels and other animals that store food in many different locations are called scatter hoarders.
The fact that squirrels are able to smell nearby nuts explains why they’re often able to find food buried by other squirrels.2 They can also sniff out some nuts more easily than others. For example, squirrels are able to smell buried walnuts from further away than buried acorns.3
1 Webster, D., Parnell, J., & Biggs, W. (1985). Mammals of the Carolinas, Virginia, and Maryland. Chapel Hill and London: The University of North Carolina Press.
2 Jacobs, L. & Liman, E. (1991). Grey squirrels remember the locations of buried nuts. The Association for the Study of Animal Behaviour, 41: 103-110. Retrieved from http://jacobs.berkeley.edu/wp-content/uploads/2015/10/Animal-Behaviour-1991-Jacobs.pdf
3 Luft, J., Malinowski, J., Briggs, J., & Smith, C. (1994). Odor as a factor in nut discovery by fox squirrels. Transactions of the Kansas Academy of Science, 97(1-2): 1-3.