North American River Otters

Photo: Creative Commons 2.0, Dmitry Azovtsev.

Check out this cute guy, or rather “dog” – that’s what male North American River Otters are called. Equally at home in the water and on land, river otters (Lontra canadensis) make their homes in a burrow near the water’s edge.

Since they were a commonly seen mammal at the time of the Expedition, there are few references to them by the journal writers. The first mention is in Patrick Gass and Joseph Whitehouse’s journal entries of Sunday, October 21, 1804, when they mention one of the hunters killed an otter along with a buffalo. River otters shouldn’t be confused with sea otters, which were well documented in the journals.

Their favorite food is fish, but they also eat amphibians, turtles, and crayfish. Otters swim by propelling themselves with their powerful tails and flexing their long bodies. They have webbed feet, water repellent fur, and nostrils and ears that close in the water. On land they can run fast, but not quite as well as they can swim.

The water mammals grow to be about 22 to 32 inches in length, weighing between 10 and 30 pounds. Average lifespan is 8 to 9 years.

River otters are found all throughout North America, inhabiting inland waterways and coastal areas, but are now rarely found in Arizona, Kansas, Nebraska, New Mexico, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, and West Virginia.