Chicago’s beloved “rat hole,” the viral sidewalk impression believed for years to be the final resting place of a cartoon-like rodent, has been officially debunked by scientific research. A new study published in Biology Letters concludes with overwhelming certainty that the famous imprint was not left by a rat, but rather by a much more common urban dweller: a squirrel. This revelation offers a fresh perspective on a local landmark that captured global attention.
The urban legend of the “Chicago rat hole,” a near-perfect animal impression on a Roscoe Village sidewalk, captured the city’s imagination and became a global phenomenon. For years, residents and visitors alike assumed the cartoon-like splat, complete with tail and claws, was the tragic imprint of a rat that met its end in wet concrete. This belief was so ingrained that people flocked to the site, leaving offerings and turning it into an unexpected cultural landmark.
The hole’s fame skyrocketed on January 6, 2024, when Chicago comedian Winslow Dumaine posted a photograph of it on social media. What had been a local curiosity for decades suddenly became a viral sensation, drawing crowds from all over. The impression, which some affectionately dubbed “Splatatouille,” even inspired an engagement, a marriage proposal, and a music festival, showcasing its unique place in Chicago lore.
Unmasking the Culprit: A Deep Dive into the Sidewalk Anomaly
Despite the widespread acceptance of its rat-centric origin, some locals harbored doubts. Now, a groundbreaking scientific study has definitively challenged the long-held assumption. Published in the journal Biology Letters, researchers from the University of Tennessee, New York Institute of Technology College of Osteopathic Medicine, and the University of Calgary conducted the first-ever scientific analysis of the famous imprint.
Unable to access the original concrete slab directly—as it has since been removed—the team, led by evolutionary biomechanist Dr. Michael Granatosky, meticulously analyzed online photographs of the hole. They used objects left inside the impression for scale and compared the anatomical measurements of the body, tail, and claw outlines to museum specimens of animals commonly found in the Chicago area. This included brown rats, mice, chipmunks, muskrats, and various squirrel species.
The results were conclusive. “Our analyses offer little support for the hypothesis that the ‘Chicago Rat Hole’ was made by a brown rat,” the study stated, suggesting instead that the impression most closely resembles an eastern grey squirrel or a fox squirrel. While a muskrat was also considered, the eastern gray squirrel emerged as the most probable suspect, given its abundance in Chicago’s urban environment. The researchers concluded there was a “98.67% likelihood” that a squirrel was the true culprit, as reported by ABC News.
Why Not a Rat? The Evidence Mounts Against the Rodent
The scientific findings provide compelling reasons why the imprint was unlikely to be a rat:
- Anatomical Discrepancies: The creature’s long forelimbs, distinct third digits, and hind paws were significantly too large to have been made by a typical brown rat. These measurements fell squarely within the ranges for squirrels and muskrats.
- Activity Patterns: Concrete is typically wet during the daytime hours when construction workers are active. Rats are predominantly nocturnal, making it less probable for one to get trapped in fresh cement during the day. Squirrels, conversely, are highly active during daylight hours.
- Lack of Tracks: A notable absence of footprints surrounding the impression further supports the squirrel theory. This suggests the animal likely fell onto the slab from above, rather than scurrying onto it from ground level. As the study theorized, a squirrel, despite its agility, may have misjudged a leap or slipped from a nearby branch and landed unexpectedly in the wet concrete.
But what about the absence of a distinct, bushy tail imprint? The researchers addressed this common query directly. Hair, unlike bone or muscle, typically lacks the rigidity required to create deep, well-defined impressions in substrates like wet cement. Therefore, it would have been highly surprising if a bushy tail had been preserved in such detail, and its absence does not negate the squirrel hypothesis.
From Sidewalk Star to Museum Piece: The Hole’s Enduring Legacy
The “rat hole’s” burgeoning popularity, while fascinating, also brought its challenges. The constant stream of tourists and admirers led to complaints from neighbors in Roscoe Village. In April 2024, an unknown individual filled the impression with a plaster-like substance, an act that was quickly undone by concerned “Good Samaritans” who immediately excavated it, as documented by ABC7 Chicago.
The story took another turn when city workers eventually removed the entire slab of sidewalk containing the impression. However, in a testament to its cultural significance, the unique artifact was not discarded. Instead, it was carefully preserved and moved to the Chicago City Hall-County Building, securing its place in the city’s history. A plaque still remains at the original Roscoe Street site, commemorating the beloved, if misidentified, landmark.
A New Identity: The ‘Windy City Sidewalk Squirrel’
In light of their findings, the research team has proposed a fitting new name for the iconic imprint: the “Windy City Sidewalk Squirrel.” This new moniker, they argue, is “more fitting of its likely origins and more aligned with the evidence at hand.” While perhaps slightly less dramatic than a rat’s tragic end, the reality of a squirrel’s accidental tumble into wet cement offers a charming and scientifically sound explanation for one of Chicago’s most peculiar attractions.
This light-hearted study also underscores a more profound point: the unexpected value of social media in connecting the public with the wild animals that share our urban spaces. What began as a viral photo ended with a scientific inquiry that engaged thousands, highlighting the hidden biodiversity in our biggest cities and fostering a new appreciation for the natural world that exists alongside us, often in plain sight.
