Their range is immediately obvious: trees felled right beside waterways, with the stumps terminating in points, where they've been gnawed away, and if there's enough room, broad pools dammed with the felled trees that look totally unlike any other dams you'll ever see because they are somehow cleverly exactly level at the high water point, with the water pouring over the top along the entire breadth of the dam, and out in the middle in deeper water a huge hump where they live.

Muskrats are likewise particularly easy to spot: a huge lake with a wake progressing across it with no visible source. They swim with just their nose barely above the water, so they're practically invisible save for the wake.