Muskrats can live in almost any place with sources of open freshwater, such as lakes, slow-moving rivers, marshes, and ponds. They can tolerate a moderate amount of pollution in the water and may even be found near large cities. In order to stay close to their aquatic food sources, muskrats often burrow into the sides of steep embankments, concealing den entrances beneath the surface of the water. If no suitable riverbanks are available, muskrats build dome-shaped lodges in the water from stems, roots, and mud, which serve as shelters from predators and adverse weather.