The North American river otter (Lontra canadensis), also known as the northern river otter and river otter, is a semiaquatic mammal that only lives on the North American continent, along its waterways and coasts. An adult North American river otter can weigh between 50.0 and 140 kg (110.2 and 308.6 lb). The river otter is protected and insulated by a thick, water-repellent coat of fur.
River Otter 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.
River Otter Appearance
The River Otter is built for swimming – they have a streamlined body, short legs with webbed feet, dense fur that keeps them warm, a tapered tail, small ears, and nostrils that can close underwater. They can grow to be more than a meter long, from head to tail, and weight up to 14 kg. Males are larger in size than females.
Unlike many warm-blooded animals that spend time in cold waters, they do not have an insulating layer of blubber to keep them warm. Instead, they rely on a thick double coat. Their water-resistant fur must be groomed frequently to provide protection and warmth. Rather than shedding seasonally, they can regulate their temperature by fluffing their fur to trap air, which acts as insulation. Outer guard hairs protect the insulating underlayer.
River Otter Habitat
River otters can live in either fresh or marine water. They make their homes in riparian zones, which are areas where land and water intersect. This can be along rivers, streams, ponds, lakes, and even marshes.
The river otter has an adaptability that allows it to easily live in a wide range of climates, from warm to cold, and from coastal marshes to higher elevations. What these mammals don’t care about, however, is human disturbance. They are shy and prefer clean water, which leads them to areas where the pressures of civilization are less.
In cold weather, however, they become active during the day, taking advantage of the warmer days to hunt and explore, and retreat to their nests during the night. If the surface of the water is frozen, otters can find crevices or weak areas to dive into and find food. The hibernation of other species can make it more difficult to find a meal. During the colder months, crayfish do well in cold water, which is an important part of the otters’ diet.
River Otter Diet
The otter’s location factors into its ideal diet. Fish is a preferred food, of course, but they also eat crayfish, snails, small turtles, freshwater clams, mussels, frogs, and salamanders. They can also make a meal out of small mammals, such as mice, as well as birds and eggs.
Predators and Threats
The biggest threat to this species is habitat loss. They prefer clean, clear water, which is often lost as it grows. Predators they should watch out for include mountain lions, black bears, coyotes, wolves, and even crocodiles. In the water, the otters are almost untouchable, with powerful swimming abilities, agility, and ferocious bites. Most of the risks they face arise from grounding on dry soil.
Reproduction and Life Cycle
The reproductive life cycle of river otters is unclear. These creatures are difficult to study in the wild, so scientists are uncertain about many aspects of their mating rituals. Some studies indicate that they mate for life, while others suggest that mating lasts only a few months.
Once mating occurs, there is a delay in the nesting process. Implantation can be delayed for 9 to 11 months and is followed by a 60-day gestation period. Otters usually lay in March and April. Newborn otters are born completely helpless, with eyes closed and without teeth. During this stage, males present to mate will be evicted from the burrow. It will return once the cubs are weaned and mobile. Then he will help raise the children.
The young stay in their nest for the first two months of their life. Once they leave the nest, they will continue to nurse for another month or so, even as they eat solid food. Natural swimmers, most pups require some initial encouragement from their mother before getting in the water for the first time.
One of the fun facts about these mammals is that they remain together as a family unit until the young are around 8 months old. At that point, the mother often has another litter, and the young are ready to move on. They will not be ready to have their own families for another year or two.
River Otter Facts!
- River otters can hold their breath for up to 8 minutes while under water.
- River otters spend two-thirds of the time on land.
- Otters always wash themselves after every meal.
- River otters can dive to a depth of 60 feet.
River Otter FAQs (Frequently Asked Questions)
They have a thick coat of fur that protects them while swimming in cold rivers. Shedding is not an issue, but the otter spends a great deal of time grooming itself. Rubbing and rolling on grass and bark keep the coat in good condition, providing insulation and warmth in the often cold waters where they swim.
The river otter most often lives alone or as a pair, but they do socialize in larger groups. They are active and playful when interacting with each other. They are not aggressive towards humans, but will typically avoid encounters when possible.
The river otter, a North American species of otter, has a habitat that extends as far north as Canada and as far south as the Rio Grande River. They do not live in arid, desert areas or the tree-less arctic region. They are flexible about their aquatic habitat and can live in rivers, streams, ponds, lakes, and marshes.
The nesting location of river otters depends on several factors. North American river otters may choose to build a nest in a burrow abandoned by another mammal. They can also nest in natural cavities, such as the area under a fallen log. Their nest has an entrance to the water. From there, a tunnel leads to the nesting area, where they lined with grass, bark, moss, leaves and hair.