Otters live in dens, usually borrowed from beavers, muskrats or woodchucks. Brush piles and root areas under large trees are used as temporary homes. Beavers are important to otters, for the dens they build, and because beaver ponds make ideal otter habitat. Dens have openings above water in summer, but in winter these are closed and the only entrance is below water. The entrance opens up to a large nest chamber, which may have a bare floor or a slight accumulation of leaves or grass.
River otters require a large amount of space.
This home range varies considerably depending on age, gender and food availability. Throughout a year, an otter may occupy 50 or more miles of a stream. Otters may occupy only a few miles of stream, but often move from one area to another. They use their keen sense of touch to find and catch their underwater target. Their sensitive facial whiskers easily detect moving prey.