The North American river otter (lontra Canadensis), also known as they river otter, are small semi-aquatic mammals commonly found in the North American continent along the waterways and coasts. River otters have existed for a very long time. Archeologists have discovered fossils that date back as old as 200 B. C. Otters body form have remained unchanged for 30 million years. They have gone under slow subtle evolutionary changes over that time period, but have retained the same body shape. The North American River otter is the largest member of the mustelidae family.
Their body is long and slender and they have a long tail that tapers behind them to a point (angel fire). The river otter has fully webbed feet that are very strong, and five toes ending in sharp claws ( brown). Their neck is long and their legs are short. Otters head is flat and has whiskers on its face, with small ears and no hair on the diamond-shaped nose. River otters show sexual dimorphism, where full grown the male is 5 % slightly larger then the females (adw). Fully grown they are generally 3’ to over 4’ ft long and weigh 11 to 23 pounds. They stand at 10 inches from the shoulder.
They also have a tail is usually 12-18 inches long. (angel fire). The river otter has webbed feet to help them swim faster in the water and run faster on land since they are semi-aquatic mammals (ludist). North American river otters have a thick, velvety fur that consist of two layers that is usually black, reddish, or grey-brown on the back and light or grey-brown on the belly. The throat and cheeks are yellow-grey color. (angel fire). They also have coarse, dense, dark hairs on their back called, guard hairs, that make their fur water resistant.
The guard hairs are thick and about 17 to 20 mm long, and the under fur is 8 to 9 mm long. North American river otters are well suited for life in the water, with a nose and ears that can close while swimming under water. The eyes have a third clear eyelid that protects the eye underwater. Otters also have oily fur and a layer of fat keep that keep their bodies warm in cold water temperatures. The otters sensitive whiskers and sharp sense of smell help them food in the water (adw). The North American River Otter is a predator carnivores adapted to hunting n the water feeding on aquatic and semi-aquatic animals.
Their diet is mainly made up of crustaceans such as; crayfishes, crabs, and other aquatic invertebrates such as fishes and small amphibians like frogs. Despite concern that otters compete with game fishers, the fishes that otters consume are mainly non-game species. Otters may also occasionally prey on birds, rabbits, and rodents (SeaWorld). Otters hunt by using their vibrissae to detect movements of prey in the water and they catch prey with their teeth.
The river otter eats about 15% to 20% of their total body weight each day (SeaWorld) Otters can swim by quadru-pedal paddling, forelimb paddling, alternate hind-limb paddling, or simultaneous hind-limb paddling. Their tail, which is a little hefty and bigger then the rest of their limbs, is used for stability in the water and to help them swim through short bursts of fast propulsion. While swimming above water the otter must remain in motion to stay afloat; and must expose its eyes, ears, and nostrils. (serge) As well as being amazing swimmers, the otter is also does great on land.
This little creature is able to walk, run, or even slide across muddy mountain side embankments or icy slopes during the winter. The river otter is able to travel up to 42 km in one day. (serge) Through out the years otters have been observed “playing” behavior. One form of play for otter is considered to be sliding. Otters have been seen climing slopes and sliding down as a form of not only low energy travel but as well as playful behavior (seaworld) Some otters even like to play wrestle, while others have been seen chasing each other as a common game. (serge)
River otters and giant otters hunt by using their wiskers to detect movements of prey in the water. They catch prey with their teeth and use their fore limbs to hold it. ( sea world) They also hunt by diving and chasing fish, or by digging in the bottom of ponds and streams. Even though otters are expert divers, hunting is not always successful. The success of catching food on a dive is less then 20%. (ludist) When otters are eating their prey, they start by eating head first and then discard the fish fins. After eating, they clean their face and whiskers by rubbing them on the grass or snow ( river otter).