Muskrats are small, aquatic rodents, 16 to 25 inches in length, including the long tail. Their fur is typically dark brown, with the underside considerably lighter than the back. Muskrats inhabit aquatic areas of still or slow moving water. They can be found living in ponds, lakes, streams, swamps, marshes and drainage ditches. Muskrats are most likely to cause problems by burrowing into pond and lake shorelines, dams, and water control structures.