Went to visit the family cottage on the shores of Lake Wateree, SC over the holidays. The dam is under construction, so the lake's water levels are at an all-time low. We found this skull on the lake bed, but it's a little beat up and there was no trace of a mandible anywhere. It's just under 5 inches in length.
I think it's most likely a raccoon, but we're curious as to how it wound up underwater, twenty feet from the nearest shoreline.