From Ohio History Central
The giant beaver, Castoroides ohioensis, is comparatively well known from Ohio’s Pleistocene sediments, with 15 specimens recorded. This black-bear sized rodent looked similar to modern beaver, Castor canadensis, but was much larger. It has been suggested that giant beaver did not build dams or gnaw on trees, but fed on aquatic vegetation. The first known and described specimen of giant beaver (type specimen) was found near Nashport, Muskingum County, and was illustrated in 1838 by the first Geological Survey of Ohio. Specimens of giant beaver fossils are displayed at the Ohio Historical Society.
In addition to modern beaver, Pleistocene sediments in Ohio have produced remains of small mammals such as shrews, bats, red squirrel, tree squirrel, voles, and field mice. Medium-sized mammals include woodchuck, porcupine, muskrat, weasel, pine marten, fisher, mink, skunk, red fox, raccoon, and river otter. Most of these remains have come from cave or bog sites that have been systematically excavated.
- Hansen, M. C., 1996. "Phylum Chordata--Vertebrate Fossils," in Fossils of Ohio, edited by R. M. Feldmann and Merrianne Hackathorn. Ohio Division of Geological Survey Bulletin 70, p. 288-369.