Food scarcity in colder months prompts squirrels to engage in caching, or hoarding. This involves gathering food items, such as nuts and seeds, during times of abundance and hiding them for later consumption. Caching is a calculated strategy that allows squirrels to manage a seasonal surplus of food. This preparation is important because squirrels generally do not hibernate and must remain active to survive winter.
Two Primary Caching Strategies
Squirrels employ two distinct methods for storing their winter provisions, determined largely by their species. Scatter hoarding is the technique used by most tree squirrels, such as the Eastern Gray and Fox squirrels. This involves hiding individual food items in hundreds of small, separate locations across their territory. This strategy minimizes the loss of their entire food supply if one small cache is discovered by a competitor.
The alternative method is larder hoarding, which is common among ground squirrels, such as chipmunks and Red squirrels. Larder hoarders collect large quantities of food and store it all in one or a few central, secure locations. While this single “pantry” is easier to defend and access, it carries the significant risk of total loss if the main stash is somehow compromised or stolen. Red squirrels often display a combination of both strategies, creating a large, central larder, called a midden, while also maintaining smaller scatter caches.
Defining Storage Locations
The physical locations squirrels choose for their food storage are directly related to their hoarding strategy. Scatter hoarders primarily create sub-surface caches, burying nuts and acorns in shallow holes in the soil. They also utilize natural above-ground caches by tucking food under loose bark, in tree crevices, or beneath logs.
Larder hoarders focus on creating large, permanent caches inside secure structures. This often means deep, underground burrows or large tree cavities, which serve as a central home and pantry. Scatter-hoarding squirrels sometimes use a deceptive tactic known as “fake burying,” where they dig a hole, pretend to place a nut, cover the empty spot, and then move to a new location for the actual cache. This behavior is an anti-theft measure used to mislead watching competitors.
Retrieval: Finding the Hidden Cache
Relocating thousands of tiny, scattered caches requires a sophisticated combination of sensory and cognitive abilities. Spatial memory is a primary tool for scatter hoarders, who create a mental map of their territory to recall the precise locations of their hidden food. Gray squirrels can remember the distinct location of their personal caches even when they are close to those buried by other squirrels.
While memory is crucial, olfaction (sense of smell) is also employed, especially when caches are buried under snow or debris. The keen sense of smell allows squirrels to detect the buried nut. They have also been observed using saliva on a nut before burying it, which acts as an olfactory signpost to help them find the cache later. This reliance on scent, however, also contributes to pilfering, as other animals can sometimes detect and steal a cached nut.