Overview

• Researchers report the imprint most closely matches a tree squirrel, with classifications split between eastern gray (50.67%) and fox squirrel (48.00%), and they rule out a brown rat based on limb and digit proportions.
• The team measured anatomical landmarks from public photos of the removed slab, using coins for scale, and compared them to museum specimens of eight local rodent species with statistical methods drawn from paleontology.
• Authors suggest the animal probably fell from a nearby tree into wet concrete during daytime work, noting the lack of tracks and explaining that concrete would not preserve a bushy tail’s hair.
• City crews removed the damaged sidewalk section in 2024 and preserved the slab at the Chicago City Hall-County Building, with officials indicating interest in a public display.
• The paper proposes renaming the landmark the “Windy City Sidewalk Squirrel” and emphasizes both public engagement with science and the limits of species-level certainty from trace impressions.