Congrats to Jill, who it looks like took a guess at this but got it right! This is indeed from a “gigantic extinct rodent”, the Giant Beaver Castoroides ohioensis. This is a resin cast of an original fossil, the actual specimen which you can see on exhibit at the Ohio History Center, and is one tooth of a pair upper incisors. Here’s a photo (left) of a skull, from Clinton Co. Ohio, which is also on exhibit. Note the large size of the incisors!
The Giant Beaver lived up to its name, it was BIG! The modern beaver (Castor canadensis) is the largest living rodent in North America, weighing in at up to 60 pounds, and is the second largest rodent in the world (after the capybara). But the Giant Beaver could weigh over 200 pounds and was six feet long. It was the size of a Black Bear! It’s logical to think that the Giant Beaver used its enlarged incisors to cut down really big trees, but in fact there have been no finds of Pleistocene-aged wood with tooth marks matching these large incisors. So it’s thought that they used these large teeth for procuring aquatic vegetation, and possibly for defense. There’s another large fossil rodent with huge incisors, this one from South America. Named Josephoartigasia monesi, this was basically a rat the size of a bull! Scientists think it may have used its large incisors for defense against predators such as saber-toothed cats and a giant, flightless carnivorous bird. We didn’t have the carnivorous bird here, but saber-tooth cats were certainly living with the Giant Beaver.
Ohio is a very important location for the Giant Beaver. Did you notice the scientific name of the Giant Beaver!? The species name is “ohioensis” which means “from Ohio”, and sure enough the first Giant Beaver specimen was discovered right here in Ohio! The first specimen known to science was uncovered when workers were digging for the Ohio Canal near Nashport, in Muskingum County. This specimen was described by J.W. Foster in 1838 as part of the investigations of the First Geological Survey of Ohio. Giant Beaver remains have been found from the Yukon Territory to Florida, however the area just south of the Great Lakes, especially Ohio, has the largest concentration of finds. You might remember that we did an article in this blog about researchersfrom Canada who traveled here this year to study OHC’s great collection of Giant Beavers. Their research may finally reveal the long-awaited mystery of what these giant rodents actually ate and what their role was in the ecosystem.