Giant Prehistoric Beaver Tooth Found in McHenry County

A McHenry County Conservation District maintenance worker made a stunning discovery while walking through a field in Marengo shortly before Christmas, according to media reports.

“It was large and had sweeping curve that didn’t look like it would fit on anything that’s around today,” MCCD employee Erich Parpart told the Northwest Herald.

The Illinois State Geological Society later identified the fossil, which looks like a bone or tusk, as the incisor tooth from a giant prehistoric beaver, more formerly known as the Castoroides ohioensis, according to a McHenry County Conservation District press release. The giant beaver became extinct 13,400 years ago.

This is only the 16th recorded find of the animal in the state and the first in McHenry County, according to the MCCD.

During its time, the giant beaver was the size of a black bear and inhabited lakes and ponds that were bordered by swamps. It was the largest Pleistocene rodent in North America, according to the news release.

The incisor likely came from the right side of the lower jaw and was found on conservation district land in the Kishwaukee Corridor near Marengo, according to the news release.

“We know from its teeth that the giant beaver did not fell trees, and thus did not construct dams to modify stream courses,” according to the MCCD press release. ”But its sheer size suggests it required large bodies of water, and since its skeleton indicates it was even more cumbersome on land than is the modern beaver, it seems to have been more restricted to these environments.”

Those features indicate the prehistoric beavers’ habits more so resembled the modern-day muskrat.

It’s unclear at this point when the giant tooth will be displayed for the public to see, according to the Northwest Herald.

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Learn more about the giant beaver in the Discovery.com video below.