The North American river otter (Lontra canadensis), also known as the Canadian otter, originally ranged from arctic Alaska to southern Florida and Texas, excepting the driest parts of the southwest. Aquatic mammals, they live on lakes, streams, coastal marshes, and rocky seacoasts.

Though cubs are vulnerable to snapping turtles, and to foxes, bobcats, and coyotes when they venture overland, adult river otters have few natural predators. Parasitism, disease, and malnourishment are rare. Nevertheless, by the nineteenth and twentieth centuries river otter populations declined through much of their historic range, becoming extirpated (completely eliminated) in several midwestern states and West Virginia. In New York State only remnant populations survived, in the isolation of the Adirondacks. Otters are still relatively abundant along the coasts of the Atlantic Ocean and the Gulf of Mexico, throughout the Pacific Northwest and Great Lakes states, in New York and northern New England, and across most of Canada and Alaska.