Keep the answers coming!
The thing that prompted this thread: we have a friend here in Louisiana who is a transplant from around New York area. They are a very active, outdoor, and water-sports oriented family. Recently these "items" have been appearing on their property and they were suspecting some kind of rodent (actually, they said "ferret," which isn't a rodent.....). When I told them what they were, they'd never heard of it.
.....so I'm just curious how many of you (and where you live) know.......?