Unraveling a Chicago Mystery: The Splatatouille Impostor
The peculiar footprint etched onto wet concrete on West Roscoe Street in Chicago captured the public imagination for decades. Known affectionately as the “Splatatouille” imprint, the mark inspired mystery, humor, and public debates about what creature could have left such a distinctive, elongated track. A recent scholarly turn, however, has provided a more concrete answer: the victim was most probably an eastern grey squirrel, not the brown rat that many initially suspected.
From Public Speculation to Scientific Inquiry
The original impression, which features a front paw extended and a tail angled behind, was first recognized as something unusual and memorable when a comedian posted a photo in early 2024. City officials later removed the section of pavement for repairs, amplifying interest in the trace and prompting researchers to dive into the question: who left the mark, and why?
Dr. Michael Granatosky, the study’s lead author from the University of Tennessee, Knoxville, explained that the team started with a comprehensive list of mammals known to inhabit Chicago. They narrowed the field from 37 candidates to eight plausible species after ruling out animals that were exceedingly rare or lacked similar physical features.
Among the contenders were the brown rat, eastern grey squirrel, eastern chipmunk, and muskrat. The central challenge, the researchers noted, was to compare a still-visible imprint with precise anatomical measurements from living and preserved specimens.
The Analytical Approach: Geometry Over Guesswork
With the pavement removed, the team relied on publicly available photographs of the imprint and juxtaposed them with measurements taken from museum skins of the eight candidates. The process was meticulous: they compared head width, limb proportions, and other structural cues that could be inferred from the imprint’s shape despite the absence of a full trackway.
Though no single species matched the imprint perfectly, the eastern grey squirrel, the fox squirrel, and the muskrat emerged as the closest matches. Importantly, the researchers highlighted that the eastern grey squirrel appeared most consistent with the known urban presence of these animals in Chicago. The conclusion leaned on probability and context rather than a definitive, one-to-one fossil-like match.
Why The Squirrel Makes Sense
Several factors supported the squirrel hypothesis. First, eastern grey squirrels are common in Chicago’s urban landscape, often foraging near trees and green spaces—consistent with a fall from height as indicated by some eyewitness reports. Second, the imprint’s scale could be explained by the way the concrete settled and spread when wet, potentially enlarging the footprint and distorting the original geometry. Third, the event likely occurred during the day, a time frame when squirrels are most active, aligning with the researchers’ interpretation of the wet-condition imprint.
The Labs, the Field, and the Broader Lessons
The researchers emphasize that this case study, while lighthearted on the surface, underscores a broader scientific principle: traces left by living organisms are complex and often ambiguous. Palaeontology, archaeology, and even forensic science grapple with imperfect evidence and interpretive uncertainties. Granatosky notes that when mud or concrete dries, materials spread and layers form, complicating efforts to reconstruct a precise sequence of events.
“When we step in mud, or concrete in this case, things spread out, things move, there are many different layers within the track, and so it’s a hard science,” he said. The study thus serves as a playful reminder that careful measurement, context, and cautious interpretation are essential tools in science—whether applied to ancient fossils or modern, urban curiosities.
A Nostalgic Conclusion and a Fresh Name
In a light touch to science communication, the team proposed rechristening the imprint as the “windy city sidewalk squirrel,” a name they argued more accurately reflected the evidence and the creature’s likely origin. While the physical imprint may be gone, the enduring question—what left the Splatatouille mark?—now centers on the everyday lives of wildlife that share cities with humans and the intriguing clues they leave behind.
Why It Matters Beyond a Quirky Tale
Beyond the amusement, the study demonstrates how scientific methods can illuminate even the most whimsical topics. It highlights how careful observation, hypothesis testing, and comparative anatomy can converge to produce credible, evidence-based conclusions from a single footprint. The lesson extends to all who encounter traces—whether in a muddy field, a rain-slicked sidewalk, or a sun-baked fossil bed: context matters, details matter, and science thrives on asking questions about the world around us.
