Otters have occasionally caused depredation problems at fish hatcheries and rearing areas. There, only game fish at artificially high densities are present, and the fish cannot escape capture. Otters have also been accused of damaging fur resources in some areas, but studies have shown predation on other furbearers to be very unusual. Habitat River otters are quite adaptable, utilizing a variety of habitat types. Although they frequent lakes and ponds, they typically live in marshes and along wooded rivers and streams with sloughs and backwater areas.
Otters live in dens in the ground most of the year.
Brush piles, root areas under large trees and similar sites are used as temporary homes. The presence of beavers in an area is important to otters, not only because of the dens they build, but also because the ponds created by beaver dams make ideal otter habitat. Limiting Factors River otters have been reported to live nearly 25 years in captivity and about 15 years in the wild. They have few natural enemies. On land, young otters are vulnerable to a variety of predators.