As a kid growing up on Flint Creek, we saw them occasionaly. If we ventured upriver from hickory hills we would see them come off bank as we motored upriver, like a tarzan show. I spent every warm day wade fishing, bowfishing, swimming etc. Then started towing little v bottom with Johnson 9.5 with riding lawnmower my dad had welded hitch on, down to makeshift boat ramp we made. This was in the late seventies and eighties. We were always told refuge released them to control beavers with the thinking they would not survive the winters. Don't know if any truth to that last sentence.