River Otter (Lutra canadensis)
The river otter is found only in the US and Canada. It’s part of the Mustelide family and is approximately 3–4 ft (1 m) long. They have a lifespan of 25 years in captivity and 15 years in the wild. River otters have been around a long time; fossils have been found dating back to around 200 BC. They’re excellent swimmers and divers and can swim at a speed of about seven miles per hour (12 kph), rarely making a ripple or a splash. They have built in valves and flaps to make them watertight while underwater. River otters play more than other wild animals and they’re most active at night. Their clawed and webbed feet are very good for running and swimming. The river otter’s coat can vary from a red to black. Their bellies are silvery or a red-brown. River otters communicate using chirps, chuckles, grunts, whistles and screams.
Range and habitat
River otters do well in Alaska, Canada and in the states along the Atlantic Coast. They’ve disappeared in nine states and in one Canadian province. They’re very sensitive to changes to their habitat. The main reason why river otters have disappeared in so many places is habitat destruction. They use a variety of habitats: lakes, ponds and marshes. River otters also require huge amounts of territory. In one year, a single otter may occupy over 50 miles (80 km) of a stream or a river at one point during that year. The river otter’s natural enemies include wolves, foxes and birds of prey.
Otters are carnivorous and feed on crustaceans, amphibians, reptiles, birds, insects and fish. They use their sense of touch to find and catch food underwater. Using their whiskers, they can sense the movement of their prey. They mostly hunt by diving and chasing in the water. These techniques don’t always work though. A study found that otters diving for food had only a 20% success rate. River otters catch their prey in their mouths and hold them with their forelimbs. They usually eat their food headfirst and throw away the fish fins. After they’re finished eating, river otters will clean their face and whiskers in the grass.
River otters usually travel in families but without the father, who rarely helps the mother rear the young. They reach sexual maturity at 2–3 years. They breed in March or April and birth takes place in the late winter or early spring. A litter can have one to six otter babies, or kits. The average litter has only two to three kits. The mothers are extremely devoted parents who teach the young to swim and catch prey by catching it and releasing for the young to catch. The kits grow fast and are roaming outside the den at two to three months. They can care for themselves at five or six months but they usually stay around until the next litter. They are 12 to 13 months old when they leave the den permanently.