At Five Rivers the other day, I saw a large animal surface in the middle of the lake and was sure it was a beaver. It wasn't:
Then I saw an animal swimming rapidly underwater with a long rat-like tail out behind it and was sure it was a muskrat. It wasn't:
Three turtles in all - two fighting (again) and one swimming.
This from a week earlier however (thanks for your guesses), was in fact a muskrat, churning up the mud near the side of the lake for reasons unknown:
At least these animals were all alive when I photographed them!