Original photo by Vaclav Matous/ Shutterstock
Autumn heralds the arrival of many things: pumpkin pie, crisp morning air, and, apparently, more intelligent rodents. Male squirrels get smarter in the fall due to their hippocampus (a part of the brain involved in memory) increasing in size during the caching season — the time of year when they gather even more nuts than usual. (In an especially adorable move, they stuff their snacks in their cheeks before moving their food to a more permanent storage spot.) Interestingly, female squirrel brains don’t show the same effect; researchers speculate that male squirrel brains may change in the fall to act more like the females’ brains already function all year long. The slightly bigger brains may help male squirrels remember exactly where they’ve stored their nuts, although scientists are still teasing out how.
Oops, incorrect!
It's a factChewing on all those walnuts, acorns, and almonds wears down a squirrel’s teeth to the proper length, so they don’t need to stop growing — if they did, they might get worn down too far.
Though we don’t tend to think of squirrels as especially bright, studies have shown that they and other tree-dwelling rodents have evolved larger brains compared to their burrowing counterparts. This all began some 34 million years ago, according to Dr. Ornella Bertrand of the University of Edinburgh's School of GeoSciences. There weren’t nearly as many arboreal primates back then, which allowed squirrels’ ancestors to take up residence among the leaves and branches. “When trees became available to them, squirrels’ ancestors seized the opportunity,” Bertrand explains. “This transition was a key evolutionary step for squirrels as it enabled them to acquire larger and more complex brains.” Whether it’s more than mere coincidence that male squirrels get smarter as (human) schools come back to session remains unconfirmed.
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“Squirrel” comes from a Greek word meaning “______.”
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“Squirrel” comes from a Greek word meaning “shadow tail.”
Squirrels used to be rare in U.S. cities.
Take a walk through just about any park in America and there’s a decent chance you’ll see a squirrel — they’re everywhere. This wasn’t always the case, however, and in fact squirrels used to be a rare sight in many U.S. cities. This changed in the late 19th century, when parks became more common, and urban reformers started releasing squirrels in hopes of creating “a bucolic atmosphere that was entertaining, enlightening, and salubrious,” in the words of one historian. Mission accomplished. Releasing just three squirrels in Philadelphia’s Franklin Square in 1847 led to a boom in their population, and other parks followed suit. There were thought to be more than 1,000 squirrels in New York’s Central Park by 1902, and as of 2020 there were 2,373 — yes, someone counted.
Michael Nordine is a writer and editor living in Denver. A native Angeleno, he has two cats and wishes he had more.
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