Chicago’s Rat Hole Mystery: Squirrel or Rat?

CHICAGO, IL — In January 2024, a sidewalk imprint known as the “Chicago rat hole” gained fame on social media, prompting locals to flock to the Roscoe Village site for selfies. The mark, which became a sensation after a tweet from artist Winslow Dumaine, was removed by the Chicago Department of Transportation in April 2024 due to community complaints.

However, the curious case of the imprint sparked an investigation by Dr. Michael Granatosky, an assistant professor at the University of Tennessee, Knoxville. His research aimed to uncover whether a rat really made the mark, as most locals believed. “What a great way to get the public excited about nature and the world around them,” Granatosky said.

Granatosky’s team conducted the first scientific analysis of the imprint, revealing that it likely belonged to a squirrel, not a rat. The researchers utilized techniques similar to those used in fossil studies, analyzing images of the imprint since the original cement block was no longer accessible for direct study.

They gathered various museum specimens—including brown rats, Eastern grey squirrels, and fox squirrels—and took detailed measurements to determine which animal made the mark. Initial findings highlighted features that hinted at a squirrel, particularly its elongated forelimbs and distinct paw measurements, which exceeded those of a rat.

Granatosky noted that the high prevalence of Eastern grey squirrels in Chicago bolstered their conclusion. Their study concluded a 98.67% likelihood the mark was made by a squirrel and a 50.67% chance it was specifically an Eastern grey squirrel.

Dr. Seth Magle, from the Urban Wildlife Institute at Lincoln Park Zoo, commented on the findings, aligning with his initial suspicions. He had previously suggested that the animal likely fell to create the mark. Magle explained that nobody saw any paw prints leading to the spot, further indicating an unexpected incident.

Gage, from the Chicago Department of Streets and Sanitation, acknowledged the significance of the rat hole in local culture, suggesting that its name would likely remain unchanged despite the scientific findings. “We aren’t so sure people will be swayed by the study to refer to it as anything else,” Gage said.

As for Dumaine, the social media influencer who sparked the rat hole craze, he accepts the new findings but maintains that the name will endure. He remarked, “The rodent responsible for the Chicago Rat Hole does not need to be a rat to accomplish the very same,” highlighting the mark’s resonance with the public amid challenging times.