River otters are active hunters in aquatic environments, targeting fish, crustaceans, frogs, birds, small mammals and any prey they can overpower. They hunt either alone or cooperatively; groups of otters may drive fish into shallows.
North American river otters have few natural predators. There are scattered records of large carnivores like gray wolves taking them, but, on the whole, the otter's aquatic nature, general tenacity and moderate size seem to keep it relatively unmolested by other creatures. Nonetheless, they share habitat with plenty of predators capable of killing adult and baby otters, or kits. Besides wolves, these include grizzly and black bears, pumas, wolverines, coyotes, golden eagles, American alligators and crocodiles, bobcats, and lynx.
River otters compete with other carnivores like coyotes, foxes, bobcats, mink and fish-eating raptors. Coyotes have been observed attempting to steal fish from river otters in Yellowstone National Park, but not always successfully. Bald eagles will also try to pirate otter catches.
Otters have historically been commercially valuable as fur-bearing aniamls. Otters target some of the same fish and even waterfowl as humans, but this normal predation should be considered in the context of their overall ecological importance.
River otters have been observed utilizing beaver lodges as shelter. In addition, the immense effects that beavers have on riparian habitats, namely creating ponds and pools from streams, may have a positive impact on otter hunting habitat.
