Squirrels use sophisticated technique to separate nuts by type, study finds

BERKELEY, Calif. — Some squirrels go a little nuts when it comes to sorting their acorns, a new study finds. Researchers at UC Berkeley observed the behavior of 45 nearby fox squirrels over a two-year period, finding that they use what’s known as a “chunking” behavior — organizing items into various smaller subsets in order to better manage the overall collection — to categorize their various nuts. 

This is notable because humans also use chunking techniques, although generally for storing information, whether the data is of a spatial, linguistic, or mathematical variety. Taking your email, for example, and dividing the messages into various folders could be considered a form of chunking.

Fox squirrels use this strategy to divide the nuts they gather over a year — between 3,000 and 10,000 — into what the researchers term “subfolders,” one for each type of nut.

“This is the first demonstration of chunking in a scatter-hoarding animal, and also suggests that squirrels use flexible strategies to store food depending on how they acquire food,” says lead author Mikel Delgado in a university news release.

The researchers believe that this idiosyncratic behavior allows squirrels to both remember where specific morsels are, and to hide other treats from animals that could steal them.

“Squirrels may use chunking the same way you put away your groceries. You might put fruit on one shelf and vegetables on another. Then, when you’re looking for an onion, you only have to look in one place, not every shelf in the kitchen,” adds Lucia Jacobs, the study’s senior author.

YouTube video

These findings were discovered through the study’s principal experiment in which the squirrels examined were subjected to a variety of conditions relating to the locations and types of nuts provided. The authors provided the squirrels with almonds, pecans, hazelnuts and walnuts and monitored via GPS tracking where on the university’s campus the critters would bury their bounty during the two-year experiment.

To determine whether the way they were being fed mattered in the experiment, the authors gave some squirrels their nuts in organized rows of fours, while others were given them in a random order. Some were fed the nuts at the site where they last buried a nut, and some were fed at a fixed location.

The rodents, regardless of where they encountered or kept their nuts, were prone to separating them, even if they did so unconsciously.

“These observations suggest that when lacking the cognitive anchor of a central food source, fox squirrels utilize a different and perhaps simpler heuristic (problem-solving approach) to simply avoid the areas where they had previously cached,” the researchers conclude.

The full study was published last month in the journal Royal Society Open Science.

Comments

  1. A conclusion anyone would have arrived at upon observing activity in any forest north of the Mason-Dixon line this time of the year.

  2. I would like to know how the study was funded. Taxpayer funding for this sort of thing is driving the deficit through the roof. If it was privately funded or self funded in some way I’m fine with it.

    Having said that, it may not seem like useful information but such things build knowledge. Major breakthroughs are seldom made in isolation, they build upon thousands of data points collected in small studies like this.

    1. I really cannot foresee any useful “major breakthrough” based upon the discovery that squirrels like to organize their nuts. What is anybody supposed to do with that exactly?

      1. Brake harder to avoid hitting the next obsessive-compulsive squirrel that bounds into traffic?

      2. I don’t know, no one does. Who would have thought early research into semiconductors would be useful?

      3. You gotta be kidding me, right? You’re going to compare Michael Faraday and others experimenting with electricity (which already was proving itself to be useful to mankind) to somebody observing that squirrels organize nuts? Ha!

      4. The point is no one knew what those early experiments would yield for society. At the time it was just tinkering around with weird junk. No one thought it would amount to much of anything. No need to be obtuse.

      5. This is deceptively false. It is fair to say that nobody knew for certain what technology would achieve, but the reality is that philosophers and scientists have been using deductive reasoning to make good educated guesses at the potential for certain types of research. For example Alexander Fleming was actually trying to discover a “wonder drug” because he accurately predicted what the potential would be if he succeeded.

        And regarding the theory of relativity, intellectuals have recognized a great importance regarding the subject of physics for thousands of years. Its understanding was integral even to the ancient Greeks and so it has always been seen as an important subject. So many great achievements have come from that field of study therefore anybody can rightly assume that more great achievements will come out of it. Physics is not “weird junk”. Wanting to create a wonder drug is not tinkering around with “weird junk”.

        These great breakthroughs all have something in common: the person was attempting to achieve something that was already objectively understood to have a value to mankind, before the discovery was made. It’s value was not only known after the discovery.

    2. I imagine this was done by students as part of their “education”. It’s typical for schools to charge a lot of money from their students to attend, then use the students time to produce “studies” and designs for which they will not get paid for.

  3. Though it seems like a huge waste of resources, I’m rather impressed that they didn’t decide to study nut allergies in squirrels.

  4. I’m no scholar, but I think these comments are pathetic.

    Everybody trying to show how clever they are, whilst in reality the squirrels have more dignity…

  5. If anybody knows anything about nuts it is Berkeley. I will brake down one sentence to prove my point. “The rodents, regardless of where they
    encountered or kept their nuts, were prone to separating them, even if
    they did so unconsciously”.
    Rodents = Students
    Encountered = Gender inequality, who or how to identify and address the Rodent
    Kept Their Nuts = Separated, Black nut from the White nuts not to hurt anybodies feelings their will be no white privilege at Berkeley
    Unconsciously = Professors, how they teach and the School board, the curriculum that is taught, all Unconsciously
    I bet when the showed the students a squirrel have of them passed out and the other half ran for their very lives. Good thing the squirrels didn’t have to go to Berkeley or they would have all starved while they put them in their safe spaces while the professors fondled their nuts trying to figure out their gender.

  6. When I saw “chunking” I thought they were going to prove that squirrels had been taught Common Core math…

  7. My wife feeds the squirrels in our neighborhood peanuts all year long.
    Little rats gave up sorting and storing long ago.

    They now actually sit by the door waiting for her.
    I had one (no lie) come up and tap me on the leg.

    They are all fat, lazy and demand food.
    Probably have coronary disease and are diabetic.

    In short, She turned them all into liberal Democrats.

  8. The article talks about fox squirrels, but the picture to me above looks like a gray squirrel. Are the ones in the video fox squirrels, most I’ve seen have much more orange color in their fur.

  9. Evolution not design. Right? Who would have thought that squirrels that did not organize would have gone extinct? Isn’t that what evolution teaches? Obviously there must have been squirrels along the evolutionary trail that could not organize their nuts and, therefore, went extinct. In other words, the ability of a squirrel to organize their food source must be key to their survival or why would they have “evolved” this instinct? The more we learn of how God gave each creature unique instincts the more we have to admit there is too much order in our universe for the statistically impossible “randomness” of evolution.

  10. It’s said that even a blind squirrel occasionally finds a nut.
    So it goes with this tremendous waste of money for ridiculous studies. Occasionally, we are maybe just slightly surprised to learn of yet another creature that is far more sophisticated, tolerant and peaceful than a Berkeley liberal.

  11. I had to look it up. Berkeley, California, really: “hierarchical”, “Though Process” ;right, not a liberal traits.
    chunking behavior: Sequence learning and production is a hierarchical process, such as in speech organization, behavioral sequences, and thought processes.


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