MARENGO – It looked like a bone, but it was too heavy and had lines like nothing Erich Parpart had seen on a bone.
The McHenry County Conservation District maintenance worker was out with a crew not long before Christmas, walking through a field in the nearly 3,000-acre Kishwaukee Corridor near Marengo and looking for concrete foundations of long-gone buildings.
Their findings would be put in a report compiled with the end goal of removing the foundations as part of a future ecological restoration project.
Parpart’s unexpected discovery sat in the maintenance shop for a few days, everyone taking a stab at guessing what it could be. A tusk – maybe from a mammoth? A Tyrannosaurus rex bone? A cow bone?
Parpart, a Wonder Lake resident who has been with the conservation district about a year, knew it wasn’t a cow bone. He was raised on a farm outside Madison, Wisconsin, and grew up digging cow bones out of fields. His guess was a tooth or tusk.
“It was large and had sweeping curve that didn’t look like it would fit on anything that’s around today,” he said.
Eventually, it made its way to the Illinois State Museum where JJ Saunders, a curator and chairman of the museum’s geology department, identified it as a fossilized giant beaver incisor, a prehistoric beaver that was about 8 feet long from tail to snout.
The incisor likely came from the right side of the beaver’s lower jaw, Saunders said in a news release.
“The giant beaver was the largest Pleistocene rodent in North America,” Saunders said. “It was an animal the size of a black bear inhabiting lakes and ponds bordered by swamps. We know from its teeth that the giant beaver did not fell trees, and thus did not construct dams to modify stream courses.”
The species became extinct about 13,400 years ago.
The incisor marks the 16th recorded find of the animal in Illinois and the first in McHenry County, the release said.
A date has not been set for when the fossilized tooth will go on display, it said.