Whole family of beavers have moved into the river out back. They've completely damned it up wall to wall in like 3 days, pretty impressive.
At one point we counted 6 of them swimming around. Probably mom, dad, and four kids. They drop a couple mature trees a night and mow vegetation down like crazy.
The work ethic is impressive though, they've got rocks and mud on top of their dam which is about 18" tall so far.