North American River Otter

The North American river otter (Lontra canadensis) is found in almost every state, including Virginia. River otters spend most of their time alone and periodically socialize in pairs or groups.

River otters have many attributes that help them adapt to life in the water. These include a heavy coat of fur, a streamlined body for swimming and special teeth for their carnivorous diet. An otter’s fur is extremely functional for life in the water. It’s incredibly dense with two distinct coats – a long, coarse outer coat (guard hairs) and a short and wooly undercoat that traps air and insulates. This double layer, along with their oil-producing glands, keeps an otter warm, especially in the cold winter months. Otters must clean their fur often to retain its water-repellent qualities. They do this by rolling or rubbing on sand, grass or snow. An otter’s skull is broad and flat with a nose up high for underwater breathing. Their nostrils can close off and their ears can shut with flaps to prevent water from entering their nose and ears. The structure of their eyeball allows them to see clearly underwater by focusing more on objects.

Otters are predominantly carnivorous, eating mainly fish, crayfish and insect larvae. They use their twelve sharp, straight-edged incisors for biting off small pieces of meat. An interesting behavioral trait of the river otter is where he eats his prey once he has caught it. They sometimes take their food out of the water and eat it on shore, even though there may be other predators waiting to steal a bite. The best way to learn about the behavioral and physical adaptations that help this mammal survive is to watch an otter on land and in the water.

As suited as the North American river otter is to its riparian habitat, these mammals were once considered a conservation concern. Much of their habitat had been destroyed by filling wetlands and polluting rivers and streams. In the past, they were hunted extensively for their valuable fur and were killed to prevent the taking of valuable “sport fish” away from fishermen. Virginia currently allows otters to be hunted east of the Blue Ridge Mountains, due to otter populations rebounding. This rebound is partially due to improving water quality in some rivers.