Another, less desirable, critter was on the pond Sunday. The beastie giving you the evil eye in the photo above is a nutria or coypu, Myocastor coypus. These are not native to our area and they compete with our native muskrats. Not an animal that I like to see when I'm out on the pond.
Here's a shot of nutria scat. In Mammals of the Eastern United States, by John O. Whitaker and William J. Hamilton, the droppings are described as "...oblong, about 5 cm (2 inches) long, and finely grooved longitudinally."