Chicago's viral 'rat hole' wasn't a rat after all, study suggests

Study suggests Chicago's 'rat hole' wasn't a rat after all

The ?Chicago Rat Hole" mystery is likely solved, as it appears it's not a rat after all. It?s nuttier than you think.

CHICAGO - More than a year after it became a social media sensation, a new study suggests the "Chicago Rat Hole" on a North Side sidewalk wasn’t a rat but probably a squirrel.

What we know:

In an article first published by The Royal Society, researchers compared the concrete imprint’s proportions to museum specimens of eight rodent species.

Using photographs of the impression, they found the limbs and digits were too long for a brown rat.

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Instead, the shape closely matched that of an eastern gray squirrel or fox squirrel. Because gray squirrels are far more common in the Chicago area, scientists concluded there’s a 98.67% chance the imprint came from one.

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The study suggests the squirrel likely slipped from a tree branch and landed on wet concrete sometime in the early 2000s.

The findings recommend renaming the imprint the "Windy City Sidewalk Squirrel."

The backstory:

The imprint went viral in 2024 after Chicago artist and comedian Winslow Dumaine posted a photo on X, calling it the "Chicago Rat Hole."

Within days, it had millions of views and drew crowds of visitors to the 1900 block of West Roscoe Street. People left offerings like coins, flowers, and trinkets, and one couple even held a "rat hole" wedding at the site.

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The city later removed the concrete to manage the crowds. Streets and Sanitation Commissioner Cole Stallard previously said the slab, now under glass at City Hall, is "in good hands."

City officials have said they’d like to display the imprint publicly.