The sight of a squirrel diligently burying a nut is common in many neighborhoods and natural spaces. These small, bushy-tailed rodents are often seen digging small holes and depositing their treasures. This activity sparks curiosity about why they do it and how they locate their hidden stashes later.
Storing Food for Lean Times
Squirrels bury nuts primarily to secure food for periods when resources are scarce, particularly during colder winter months. This behavior is known as “caching” or “hoarding.” Squirrels predominantly use “scatter hoarding,” distributing individual nuts or small clusters across numerous shallow caches over a wide area. This differs from “larder hoarding,” a less common strategy for squirrels, which concentrates a large quantity of food in a single location.
Scatter hoarding helps mitigate the risk of losing an entire food supply if one cache is discovered by another animal. Squirrels typically bury acorns, hickory nuts, pecans, and other seeds, which provide essential fats, proteins, and carbohydrates necessary for their survival. They assess nut quality by smell and manipulation, selecting viable nuts for caching. In autumn, a single squirrel might bury thousands of nuts, preparing for lean times when fresh food is difficult to find.
Retrieving Buried Treasures
Squirrels use a sophisticated combination of memory and their highly developed sense of smell to locate buried nuts. While once thought to rely mostly on scent, studies show spatial memory plays a significant role in recalling cache locations. Squirrels create mental maps of their territory, remembering landmarks like trees or rocks near their hidden stashes. This cognitive mapping allows them to return to the general vicinity of thousands of individual caches.
Once in the general area, their keen sense of smell helps them pinpoint the exact location of buried nuts, even under layers of snow or leaf litter. They may also “re-cache,” moving nuts to new locations to refresh memory or protect them from potential thieves. Despite their retrieval abilities, squirrels do not find every nut they bury; they recover a large proportion, but not all.
Accidental Tree Planters
The caching behavior of squirrels has a significant unintended ecological benefit: forest regeneration. When squirrels fail to recover all buried nuts, these forgotten seeds often germinate and grow into new trees. This is especially true for large seeds like acorns, a primary food source for many squirrel species.
By burying seeds across wide areas, squirrels act as effective seed dispersers, contributing to the spread and genetic diversity of tree populations. This process is crucial for forest health and expansion, making squirrels effective tree planters. In some ecosystems, squirrels are considered among the most important animals for helping oak forests spread and regenerate.