The infamous ‘Rat Hole’ in Chicago has been revealed to be less about rats and more in line with squirrels.
Recent research has suggested it was most likely a squirrel that imprinted a rodent-like shape in the city’s concrete. This finding was published on October 15 in Biology Letters, employing paleontological methodologies to dissect this quirky urban landmark.
Michael Granatosky, a scholar in evolutionary biomechanics based at the University of Tennessee, was inspired to delve into the mystery of this years-old imprint after artist Winslow Dumaine tweeted about it in 2024. Nicknamed Splatatouille, the Chicago Rat Hole quickly garnered viral fame, with tourists to Roscoe Village leaving an array of coins, flowers, and trinkets before the slab made its way to City Hall. Despite Chicago being dubbed the “rattiest city in America, the true creator of the hole has been a subject of debate.
Granatosky muses, “Even if it wasn’t viewed through a scientific lens, there was clear deductive reasoning at play. It felt like an exciting challenge to apply the scientific method to something so whimsical.”
To capitalize on the site’s viral status, Granatosky and his team gathered numerous images. They analyzed these photographs for anatomical characteristics, such as snout-to-tail length and head width. Utilizing the app iNaturalist, they cataloged eight small mammal species known to inhabit Chicago. They then compared these measurements with those of museum specimens to draw potential correlations with the imprint.
The data indicated a close match with either an eastern gray squirrel (Sciurus carolinensis) or a fox squirrel (S. niger). Granatosky proposes that the imprint was likely created by a squirrel that fell from a tree nearby, as reported by local residents. For a rat to achieve such an impression, it would need to be dropped by a bird, given the absence of any rat tracks. Critics point out that the lack of a bushy tail in the imprint raises questions, but Granatosky contends that fine details like that are unlikely to show in concrete molds.
Despite their extensive analysis, the team could not definitively identify the creature responsible for this contemporary impression, which underscores the complexities inherent in this type of research, especially when considering ancient paleontological evidence. Granatosky hopes this study ignites discussion among peers and captures public interest, and he is also working on a lesson plan tailored for children.
“It’s not often we encounter such a playful narrative,” he adds. “It embodies the essence of our lab work, which is to transform data into formats that everyone can understand.”
