North American River Otter

Welcome to this week’s Wildlife of the Week!

Lontra canadensis North American River Otter

This week's Wildlife of the Week is a visitor favorite, the North American river otter! These endearing critters are sometimes spotted hunting and playing in the water around the Observation Building. They are not as common as two other semi-aquatic mammals often seen on the refuge, muskrats and beavers, and are often mistaken for those animals. Since all three species often present only their head and a glimpse of their tail when swimming, they look like a swimming blob of fur and identification can be difficult. There are two features that tell the difference between the three; size and the tail. First, otters are bigger than the other two and while estimating size can be difficult, otter heads appear much larger and blockier. The best identification clue is the tail. Beavers have flat, paddle like tails, muskrats have bare tails that resemble a rat, otters have long thick fur-covered tails. If you’re lucky enough to catch them out of the water, identification by observing the tail makes it easy.

They are playful and can be observed in family groups cavorting on river banks and in the water and they may emit various vocalizations including whistles and grunts while playing.

River otters are widely distributed through the United States and can be found in 45 states. The otter population in Alabama seems to be fairly large and stable. They inhabit freshwater waterways such as rivers, streams, lakes, ponds, and swamps or marshes and can travel several miles over land to find another body of water. Their diet consists of fish, crayfish, frogs, mussels, turtles, snakes and invertebrates. They are voracious eaters and are well equipped to hunt prey with long claws, sharp canine teeth and long sensitive whiskers that aid in locating and capturing prey in murky waters. They are fast and agile and can stay submerged for up to eight minutes, traits crucial to catching their equally fast and agile fish prey.

Adults may grow to 4 1/2 feet long and up to thirty pounds but normally range from 15-25 pounds. Females are smaller than males. Thick waterproof fur acts as insulation and otters remain active in cold weather. Frequent grooming retains the insulation and waterproof qualities of the fur. Fur ranges from dark brown to pale chestnut on the back and sides and light brown and gray on the belly.

The otter in the photos was photographed from the Observation Building in the Visitor Center Complex. Otters have also been observed in Dinsmore Slough, Crabtree Slough, Flint Creek near Dancy Bottoms and Blackwell Swamp.

(Photos by Tom Ress)