The North American river otter (Lontra canadensis), also known as the northern river otter or the common otter, is a semi-aquatic mammal endemic to the North American continent found in and along its waterways and coasts. An adult river otter can weigh between 5.0 and 14 kg (11.0 and 31 lb). The river otter is protected and insulated by a thick, water-repellent coat of fur.

The river otter, a member of the weasel family, is equally versatile in the water and on land. It establishes a burrow close to the water's edge in river, lake, swamp, coastal shoreline, tidal flat, or estuary ecosystems. The den typically has many tunnel openings, one of which generally allows the otter to enter and exit the body of water. Female otters give birth in these underground burrows, producing litters of one to six young.