Looks like there's beaver in that system but just passing through the area. The dam has bean worked on, but just kind of pieced together by the looks of it. That is usually the sign of a "loaner", a beaver that's lost it's mate. They tend to kind of wander around and don't get real serious about cutting a bunch of trees down of maintaining a dam. There has been good activity there in the past, looks like last year or the year before though.

They either moved on or where moved on....
Good sets there for coon, mink, otter, possibly rats - if you could use legholds