Do Squirrels Remember Where They Stored Their Food?

Analysis by Dr. Karen Shaw Becker

squirrel storing food

Story at-a-glance -

  • Squirrels seem to use a meticulous strategy in the way they store food, rather than it being a random exercise of hiding their nuts for serendipitous discovery later on
  • Animals that store food for winter either larder-hoard (store all their food in one place) or scatter-hoard (divide their booty and stash it away in several different locations), depending on the species
  • Squirrel species that bury their food have demonstrated that they can return to as much as 95 percent of the stashes they’ve buried
  • Some scientists hypothesize that squirrels must have a strong sense of smell; others say they recognize landmarks such as trees and gauge distances between themselves, the trees and their nests
  • In one study, squirrels learned how to manipulate complicated levers that would open a hatch and deliver a prized hazelnut, and remembered how to get the prize two years later

Squirrels are very industrious creatures. Whenever you happen to catch sight of one, possibly two, they always seem to be scurrying somewhere, continuously busy, always on a mission, unless they catch sight of you, at which point they freeze in place, usually with nuts in their mouths.

So that’s what they’re up to — either stockpiling for the lean days of winter or digging up the nuts they buried weeks or even months ago. If you’ve watched a squirrel for very long, perhaps you’ve mused a bit about the value of this activity as they scamper back and forth from their nut stockpiles to various hidey holes on a circuitous, seemingly random route only they remember.

But do they really remember? The premise is that once they’ve gone to all the trouble to hide those nuts in their various underground warehouses, squirrels will be able to return to them when their proverbial cupboards are bare. Live Science offers a few interesting clues on the perpetual outdoor food-hoarding endeavors undertaken by squirrels, both before and after temperatures dip:

“Animals that store food to survive the winter don’t just do so randomly: They typically use one of two strategies. Either they larder-hoard — meaning they store all their food in one place — or they scatter-hoard — meaning they split up their bounty and stash it in many different locations.”1

Most squirrels tend to be scatter-hoarders, which explains the almost frenetic dashing to and fro, says squirrel expert Mikel Maria Delgado, Ph.D., a postdoctoral fellow at the School of Veterinary Medicine at the University of California, Davis. She asserts that the more widely the nuts are distributed, the lower the risk that some other squirrel might come along and steal the stash, so to speak.

Interestingly, squirrels possess traits that help them mentally organize and arrange their hoards according to the type of nut. This behavior is known as “chunking,” which, according to the journal Royal Society Open Science, may help them remember where the nuts are interred.2

This knowledge dispels the notion that the nut-burying is random, scientists say; in fact, animals displaying this behavior usually have favorite foods and return to them first in order of preference. In addition, depending on the species:

“Squirrels respond adaptively to each nut that is encountered, adjusting eating and cache decisions to its relative value, the abundance of food, the type of food, and the perception of risk of pilfering. Squirrels cache preferred foods farther from the source, and at lower densities. Finally, squirrels have been shown to encode and recall the spatial locations of their caches.”3

Squirrels: Diet, Digs and Factoids

It may be helpful to know there are around 200 squirrel species, designated within three categories, each having several types, such as tree squirrels, ground squirrels and flying squirrels. You’ve got your American red, black, white squirrels, gray, spotted, Northern flying, Southern, Arizona gray, Idaho, Albert’s, Franklin’s, fox, pygmy and many more.4 Squirrels can be found living on every continent except Australia and Antarctica.

All the squirrel types explain their varying sizes. The African pygmy squirrel measures as small as 2.8 to 5 inches long, while the Indian giant squirrel may reach 36 inches in length, tail included, sporting coats in fascinating patch-patterns of black, brown, orange, maroon and purple.

Because the latter lives in forests of Southern India, they have a perpetual food source of bark, fruit, flowers, bird eggs and insects, and don’t appear to hide their food.5

Squirrels put away or otherwise consume, on average, about a pound of food per week, and they’re considered omnivores, sometimes eating fungi, tiny animals and even young snakes. But if nuts are the food that’s most readily available, and the climate necessitates storing away food for winter months, squirrels bury it for easy access when nothing else is easy to get to.

Ground squirrels dig burrows, which is where they live in tunnels they’ve dug, while flying squirrels frequently build nests in tree branches or find a sturdy hole. If they don’t fly, tree squirrels prepare similar habitats. Just in case, some squirrels eat extra, like bears preparing for hibernation, only squirrels don’t hibernate! Here are a few more interesting factoids from Live Science:

“A group of squirrels are called a scurry or dray. They are very territorial and will fight to the death to defend their area. Mother squirrels are the most vicious when defending their babies. Some squirrels are crepuscular. This means that they are only active at dawn and dusk …

Squirrels have four teeth in the front of their mouth that constantly grow throughout their lives. This ensures that their teeth don't wear down to nubs from gnawing on nuts and other objects.”6

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Nut-Burying Squirrels: Do They Really Remember?

Clearly, the way squirrels bury their food is not random, and neither are the methods they use to find their treasure stores again. Research reveals that instead, squirrel species that bury their food are able to retrieve up to 95 percent of what they’ve buried. One of the first questions people ask is how it works when multiple squirrels live in close proximity to each other. The answer, another study notes,7 is that in the case of grey squirrels, individuals remember and return to the exact locations of their personal hoard.

Some scientists surmised that squirrels must use their sense of smell to locate previously buried nuts, which may come into play to a degree. In areas where there’s snow, a strong smell sense becomes more of a challenge. Fortunately, other cues may explain how squirrels seem to know precisely where they put the plunder.

Delgado notes that while scatter-hoarding squirrels probably do use their noses, they also remember, and adds, “We don't know the exact mechanisms, but it probably includes spatial cues in the environment.”8

Squirrel cognition expert Pizza Ka Yee Chow, a postdoctoral research fellow at Hokkaido University in Japan, believes from her own observations that squirrels recognize landmarks such as trees and gauge distances between the trees, themselves and their nests. Others note that the gauging may also involve the distance dynamics between different caches they’ve established:

“Squirrels may even be doing quality control on their bounty. The animals have been observed pawing over nuts and seeds for long periods of time before they bury their stash — something that might help them select nuts with the highest nutritional content, and those least likely to perish under ground.”9

Long-term memory is another aspect Chow suggests in her study published in Animal Cognition.10 In it, squirrels managed to successfully manipulate levers that would open a hatch and deliver a prized hazelnut, then repeated it to get the prize two years later. What’s more, besides carefully placing leaves over the hole they’ve just buried a batch of nuts, they even pretend to bury nuts when they think other squirrels are watching. Clearly, squirrels are smarter than many of us give them credit for.