Ah, rats! Researchers say some other critter likely created Chicago's
'rat hole' sidewalk landmark
[October 16, 2025]
By TODD RICHMOND
Ah, rats!
Researchers think they have debunked the origin of Chicago's so-called
“rat hole,” one of the Windy City's weirdest local landmarks.
Hold on. The rat hole wasn't what you think. It wasn't some back alley
bar that served as a speakeasy for the city's notorious gangster
clientele or a tenement stuffed to the brim with junk. It was actually a
full-body impression of an unlucky critter that got trapped in wet
sidewalk cement in the city's Roscoe Village neighborhood about 20 or 30
years ago. The imprint closely resembles that of a spread-eagled rat,
complete with outlines of what appear to be tiny claws, arms and legs
and even a tail.
The rat hole went viral early last year after comedian Winslow Dumaine
posted a photo of it on X. The post drew curious tourists to the site at
all hours, with some leaving coins and other odd objects around the
impression as a tribute.
The constant traffic drew complaints from neighbors, though, and in
April 2024 someone filled the impression with a substance resembling
plaster. City workers eventually removed that slab of sidewalk and took
it to the City Hall-County Building. A plaque honoring the rat hole
remains at the actual site.
Researchers hailing from the University of Tennessee, New York Institute
of Technology College of Osteopathic Medicine and the University of
Calgary published a paper Wednesday in the journal Biology Letters that
concludes the rat hole was most likely created not by the titular rodent
but a squirrel or a muskrat.
The researchers studied online photos of the rat hole and compared
measurements of the imprint to museum specimens of animals commonly
found in the Chicago area. The presence of arms, legs and a tail
excluded birds, snakes, frogs and turtles, shrinking the possibilities
to a mammal. The claw outlines further reduced the field to rats, mice,
squirrels, chipmunks and muskrats, the study said.
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Chicago's iconic Rat Hole along the 1900 block of West Roscoe Street
in the Roscoe Village neighborhood is seen, Jan. 19, 2024, in
Chicago. (Tyler Pasciak LaRiviere/Chicago Sun-Times via AP, File)

The creature's long forelimbs, third digits and hind paws were too large
for a rat but fell into the measurement ranges for Eastern gray
squirrels, fox squirrels and muskrats. The most probable suspect is the
Eastern gray squirrel given how abundant that creature is in the Chicago
area, the study concluded.
Other researchers have theorized that a squirrel created the imprint,
the study acknowledged. Cement is typically wet during the day, and rats
are nocturnal and the creature didn't leave any tracks, suggesting a
squirrel misjudged a leap or slipped from a branch and landed in the wet
cement, the study noted.
The imprint didn't show any sign of a bushy tail, but hair often lacks
the rigidity to create deep, well-defined impressions, and it would have
been surprising to find such an imprint, the study said.
“We therefore propose that the specimen be rechristened the 'Windy City
Sidewalk Squirrel' — a name more fitting of its likely origins and more
aligned with the evidence at hand," they wrote.
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