River Otter



Common Name
River Otter
Lutra canadensis


Semi-aquatic mammal; short, dense, dark brown fur above, lighter brown to silver belly; long slender body; small ears; small brown eyes located toward top of skull; flat broad head; white whiskers; short legs; webbed feet, five toes; non-retractable claws; long heavy tail with fur, thick at base, narrowing toward tip; males larger than females; 36 sharp teeth
27 – 30 in. (68.58 – 76.2 cm) head and body; 13 – 17 in. (33.02 – 43.18 cm) tail; 12 – 25 lbs. (5.443 – 11.34 kg) weight 
Ecological Role
The river otter is a predator at the top of the aquatic food chain. It plays an important role in the nutrient cycle by transferring nutrients from one ecosystem to another. It takes nutrients from the aquatic ecosystem by feeding upon fish and other aquatic organisms then transfers those nutrients to the terrestrial ecosystem by depositing their waste on land. Otters tend to use the same area time after time for depositing waste and this area is referred to as a latrine. Predators such as the bald eagle may eat the pups.
Fun Facts
Otters have valves or flaps of skin that cover the nostrils and ears to keep water out when underwater. The river otter can swim on the surface or underwater. They can dive for several minutes at great depths. River otters can run fast on land and stand upright on their hind feet using their tail for balance. They can travel several miles on land to find another stream or river. Otters mark their territory with urine, feces, or a scent gland under their tail. Their flexible skeleton allows them to move their body into many positions, including a nose to tail circle. River otters are playful animals and are often found sliding down riverbanks. These paths on the riverbank are called otter slides. In Kentucky, river otters are the largest members of the Mustelidae family, which also includes skunks, weasels, and mink.
Primarily fish such as catfish and bluegill; crayfish and other aquatic invertebrates; frogs, turtles, birds, small mammals and eggs such as turtle eggs
Dens are constructed in riverbanks with entrances below and above water; female builds nest inside dens out of sticks, reeds, leaves, and grass
Early spring; mating may take place in water or on land; no strong bond between male and female, male will mate with more than one female; competition for females may occur among males; female may retain the fertilized egg for up to ten months before it attaches to the womb; this is called delayed implantation and allows the female to become more nutritionally fit; young born in two months
Streams, rivers, lakes, ponds, swamps, marshes
Kentucky Distribution
Statewide but not common
Life Cycle
Life Span
10 – 11 years 
Life Stage
Seasonal Changes
River otters are active all year. They trap air in their fur to help them stay warm. Otters waterproof their fur by spreading oil from glands that lie close to each hair.
Abundant in western Kentucky; increasing in central and eastern restoration areas
Whistle and chattering call during mating season, soft chuckle, chirp, grunt, snort, and growl
Born April – May; litter of 1 – 5; born with dark brown fur, eyes closed and no teeth; 7 – 8 in. (17.78 – 20.32cm) long and weigh 4 – 5 oz. (113.4 – 141.7 g); young are called cubs or pups; female cares for pups; male may rejoin family group in 6 – 8 weeks after young are born; begin to swim at two months; weaned at 4 – 5 months but may stay with female for up to a year; males and females able to reproduce at two years, however males may not breed successfully until 5 – 7 years old 
What We Can Do
Protect aquatic ecosystems such as wetlands and riverside habitats. Landowners can preserve and restore wetland areas. Do not put toxic chemicals into waterways that could kill aquatic organisms that otters depend upon for food. Otters are not a threat to fisheries or popular fishing spots as once believed.
Diagnosis and Control
Interesting Facts
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