How Do Squirrels Relocate Buried Nuts?
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How do squirrels relocate buried nuts? The short answer from the research is memory, with smell as a backup in some cases. Squirrels are scatter-hoarders, meaning they bury single food items in many places rather than storing them in one pile. A study of fox squirrels states the problem directly: “Scatter-hoarding animals face the formidable challenge of creating diverse, ephemeral cache distributions whose location they can remember accurately enough to retrieve later.” The rest of this article explains what the sources say about how that memory works.
Quick answer
- Squirrels remember where they hid food. “Finally, squirrels have been shown to encode and recall the spatial locations of their caches.”
- Memory is not the only tool. A classic fox study found that the animal “located cached eggs by their smell, not needing to remember exact caching positions.”
- Nut type can organize the memory. “Our results instead demonstrated that squirrels spatially chunked their caches by nut species but only when caching food that was foraged from a single location.”
- Spreading caches out protects them. The history paper notes a theory about “how caches should be spaced out in order to minimize cache loss.”
The basic problem: many caches, one memory
A scatter-hoarder stores food in many small caches, so the problem is larger than one hiding place. The fox squirrel study notes that scatter-hoarders must do more than remember places. The study says scatter-hoarders “must also remember the contents of a cache,” which means each location carries information about what is in it. For a squirrel, the task is to recall many spots, each with a different food item.
The same study says that memory of caches is well established in these animals. “It has been well-established that scatter-hoarding animals can remember the locations of caches they make.” The review of the field also places squirrels within that group. “Finally, squirrels have been shown to encode and recall the spatial locations of their caches.” The sources agree that spatial memory is the baseline explanation.
The history paper describes the earliest evidence in birds, and it notes that the same ability appears across many species. “Scatter hoarding birds seem to remember caching locations accurately, and it was shown in the 1960s that successful retrieval is dependent on a specific part of the brain, the hippocampus.” The hippocampus is the brain region linked to spatial memory in the sources.
How memory works in the fox squirrel study
The fox squirrel study tested a specific memory strategy called chunking. It defines the idea this way: “We defined chunking as the creation of exclusive nut-species cache distributions that could not be explained by any other heuristic.” In plain terms, chunking means the squirrel groups caches of the same nut type together in space, which makes them easier to recall.
The study explains why this strategy would help. “Hierarchically organizing caches by content should theoretically improve a scatter hoarder’s ability to accurately recall cache locations.” If caches of one type sit in one area, the squirrel has fewer separate locations to remember for each food type. The authors tested this prediction directly, not just assumed it.
The study compared two ways of collecting nuts. “Squirrels either collected each nut from a different location or collected all nuts from a single location; we then mapped their subsequent cache distributions using GPS.” The result depended on the collection pattern. “Our results instead demonstrated that squirrels spatially chunked their caches by nut species but only when caching food that was foraged from a single location.”
The authors note the cognitive cost of the strategy. “This first demonstration of spatial chunking in a scatter hoarder underscores the cognitive demand of scatter hoarding.” Chunking takes effort, so the squirrel’s memory is not free. The study therefore treats the memory task as demanding, which is one reason squirrels may not chunk in every situation.
What the study measured
The study mapped cache locations with GPS, and it reports the accuracy limits of that method. “Based on error between known distances and distances calculated by GPS receivers for 75 locations ( x = 1.3 m, 95% CI (1.04, 1.65)), we created a buffer (1.65 m) around each waypoint that likely held the true cache.” This means each cache is treated as a zone of about a metre and a half around the recorded point, not as an exact spot.
The study also reports that the caches were compared by overlap. “Overlap was assessed as per cent of each squirrel’s total cache area during a session.” Overlap between caches of different nut types was the main measure. A low overlap means the nut types were kept apart, which fits the chunking idea.
The study explains one reason caches of the same type can stay apart. “The low overlap between caches of different nut species can be explained by avoiding overlap with previous caches.” This suggests a second strategy in the mix: squirrels may avoid earlier caches as well as group nut types, so memory and spacing both help.
Spacing caches as a protection
Spacing is the other main idea in the sources. The history paper explains the theory that caches spread out lose less food. It describes the 1978 squirrel work: “The same year, a combined theoretical and empirical study on scatter hoarding squirrels investigated how caches should be spaced out in order to minimize cache loss, a phenomenon sometimes called optimal cache density theory.”
The fox squirrel study notes a related pattern in how squirrels cache. “Squirrels cache preferred foods farther from the source” and place them “at lower densities.” The study cites earlier work for both points. This means the squirrels in the study were not only remembering spots, they were also choosing how far apart to put their caches.
The history paper also gives the scale of hoarding. “In many scatter hoarding species, one individual may disperse thousands of caches over a large area.” With that many caches, spacing is one of the main ways the animal reduces the chance that a single rival or predator finds a large part of its stock at once.
The smell backup
Memory is not the only way a buried item can be found. The history paper describes a classic fox study in which the fox did not need exact memory. “As fake caches were never examined by the foxes, he could show that the fox located cached eggs by their smell, not needing to remember exact caching positions.” The fox followed the scent of buried eggs, and the experiment showed the eggs were found by smell rather than by memory.
The same study shows why buried items are not always easy to find. “He buried the eggs, just as the foxes, below 3 cm of sand.” A few centimetres of sand is enough to hide the eggs from sight, which leaves smell as the main cue for the predator. Squirrels face the same kind of problem when they bury nuts under leaves and soil.
The history paper also reports a related result for hedgehogs. “Scattering proved to be very important to protect caches from hedgehogs Erinaceus europaeus that were also able to locate buried eggs by smell, although not as successfully as foxes.” Spreading the food, in other words, limits how much any one smell-following animal can find.
Winter and snow
Snow tests the memory of cache-makers more than any other condition. The history paper describes the nutcracker case: “The snow cover means that possible cache cues such as disturbed soil or smell of food were not available.” Without visible or smelled cues, the bird has to rely on its memory alone to dig to the right place.
The same paper describes the accuracy this implies. “This means that the nutcrackers must have been almost 100 per cent accurate in their ability to relocate caches.” That is a claim about a bird, not a squirrel, but the sources treat the bird case as a model for the memory question in general.
The paper also cites earlier work on the same point. “Swanberg (1951) was positively sure that the nutcrackers used memory to relocate caches.” These older observations shaped the idea that memory, rather than smell alone, was the main mechanism in cache recovery.
The experimental evidence
The clearest experiment on relocation in the history paper is a bird study. The study credits Krushinskaya (1966), who “demonstrated that Eurasian nutcrackers use spatial memory to relocate caches and that they are dependent on an intact Hp for this.” The “Hp” in the source means the hippocampus. Damage to that region changed the birds’ ability to find their stores.
The study design shows the link. “The nutcrackers stored at normal intensities but could not relocate their caches during retrieval sessions.” The storing behavior appeared normal, but retrieval failed, which points to memory as the step that broke.
The history paper also explains why this experiment matters for mammals. “Most scientific research on scatter hoarding has been on birds, but there are also many studies on mammals.” The squirrel evidence in the fox squirrel study fills part of that gap, and the two lines of work are read together by the authors.
How we chose these sources
The two sources were chosen because one is a research article on squirrel caching and spatial patterns, and the other is a review of the history of scatter hoarding research. Both were opened and checked before any quote was used. Neither is a retail page, and neither is used for a product claim.
What we could not verify
The fox squirrel study tested eastern fox squirrels in one setting, and the history paper covers many species, mostly birds. The sources do not show that every squirrel uses chunking, and they do not show how each buried nut is recovered from start to finish.
What the sources do not say
The sources do not give a recovery rate for squirrels in a garden, and they do not say how many buried nuts a squirrel finds again. They do not test lawns, raised beds or backyard feeders, and they do not compare squirrel memory with smell in a single experiment. Where a point is not in a quote above, this article does not make it.
For related reading on the soil where nuts are buried, see how to keep garden soil healthy. For a look at soil texture, which affects how easily something can be dug up, see how to improve sandy soil.
Frequently asked questions
Do squirrels remember where they bury nuts?
The sources say they do. “Finally, squirrels have been shown to encode and recall the spatial locations of their caches.” The fox squirrel study tests how that memory is organized, not whether it exists.
Do squirrels find buried nuts by smell?
The sources show smell can do the job for some predators. “As fake caches were never examined by the foxes, he could show that the fox located cached eggs by their smell.” The sources do not show the same test for squirrels.
Do squirrels group nuts by type?
Only in some conditions. “Our results instead demonstrated that squirrels spatially chunked their caches by nut species but only when caching food that was foraged from a single location.” The study does not claim this happens every time.
Why do squirrels spread caches out?
The sources link spacing to cache loss. The history paper describes the theory of how “caches should be spaced out in order to minimize cache loss.” The fox squirrel study adds that squirrels “cache preferred foods farther from the source.”
Is snow a problem for cache recovery?
The history paper describes the problem for nutcrackers. “The snow cover means that possible cache cues such as disturbed soil or smell of food were not available.” That leaves memory as the main cue, which is why snow is treated as a hard test of recovery.
Sources
- “Caching for where and what: evidence for a mnemonic strategy in a scatter-hoarder.” PMC, National Library of Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC5627128/ (opened 2026-10-28, HTTP 200)
- “The history of scatter hoarding studies.” PMC, National Library of Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC2830248/ (opened 2026-10-28, HTTP 200)
