Otters are one of the largest and most social members of the weasel (or Mustelidae) family. The weasel family has been around for a long time, first appearing around 15 million years ago. This group includes almost 60 different species including mink, ferrets, badgers, martens, wolverines, and more. The Mustelidae family inhabits all continents except Antarctica and Australia. All are primarily carnivores and most are active year-round.
River otters are relatively small mammals (total length can be up to 50 inches) with elongated, heavily muscular, streamlined bodies. They live in water most of the time and are excellent swimmers.
They have adapted to a semi-aquatic lifestyle in several ways: Short, powerful legs and webbed toes make them fast swimmers (up to eight miles per hour). Their long, thick, pointed tail helps them along and can also propel them forward and act as a rudder. The dense fur keeps them warm, and they need frequent drying and brushing to maintain their insulating qualities and water resistance. Eyes and ears are set high on the supporting surface of the head when swimming. The eyes also have a protective third eyelid for swimming underwater. Only the hind legs are webbed.
Otters are short-sighted too. Even the small, rounded ears and nostrils close when the otter is underwater. They can spend up to eight minutes underwater and dive to depths of 60 feet!
Adults weigh 15 to 35 pounds and are 40 to 60 inches (102 to 152 cm) long. Females are 25 percent smaller than males. The belly is slightly lighter than the back. The chin and throat are greyish.
The North American river otter has adapted to a semi-aquatic lifestyle. It has a thick coat to keep warm in cold water, short legs, and webs to swim faster, a streamlined body, and a strong tail to move faster in the water. The otter also feels just as comfortable on land.
In fact, he can run many kilometers at a time; However, these nocturnal walks are an increasingly risky activity due to habitat changes.
This otter species is not very social: males and females only meet for courtship or mating, which takes place twice a year.
Although they can live for around eight years in the wild, they are sensitive to pollution and cannot survive in heavily polluted water.
The giant otter is the only mustelid (a member of the weasel family) that mates with a single partner. Although these otters are monogamous, they often live in family groups that include mates and young from different breeding seasons. Also known as river wolves these giant mammals can grow up to two meters long and compete with jaguars for their prey.
Its visibility is not very good, but underwater it can be better than on the surface. The animal uses multiple sets of powerful wire busts to hunt and avoid obstacles.
They travel back and forth between bodies of water several kilometers over land, developing well-defined migratory routes that are used year after year. They can dig over an area of several square meters. Feces, twisted clumps of grass, and small mounds of dirt and vegetation are common in these areas.
River otters reach maturity at 2 years of age. A female produces one litter each year.
The young are born toothless and blind in a mostly underground burrow. 7 weeks later his eyes open. When they are about 2 months old they emerge from the burrow and soon begin swimming and eating solid food. The female teaches them to swim and has to coax them or throw them into the water. They become independent after 5 months. They stay with their mother until shortly before the birth of their next litter. River otters reach sexual maturity at 2 years of age. A female will mate with the male of her choice and produce one litter each year.
Otters can live and reproduce for more than 20 years.
River otters in Alaska hunt on land and in fresh and saltwater. They feed on snails, clams, clams, sea urchins, insects, crabs, shrimp, squid, frogs, a variety of fish, and occasionally birds, mammals, and plant matter. Aquatic organisms no longer than a finger are usually eaten at the surface. from the water; the larger meal is brought ashore.
Otters travel together and function as a social unit but do not cooperate in hunting or sharing what is caught. Otter fights are extremely rare, although they are wary of strange individuals.
The river otter’s range includes rivers, streams, lakes, estuaries, marshes, and major marine waterways, mainly west of the Cascade Range. A river otter’s home range can be as large as 30 square miles. basins and tributaries and can cover up to 18 miles in a day.
Otters are constantly on the move, especially the males, which have been known to travel up to 150 miles each year. Females with young will travel, but not as far.
A good part of the movement is hunting. River otters have an amazing sense of smell and can sniff out and hunt large numbers of fish upriver from great distances.
Otters spend most of their time in the water. About a third of the time they are on land. They often make extensive overland excursions from one habitat to another.
Although fish is the favorite, river otters also eat crustaceans (like crabs, shrimp, and barnacles), amphibians (like frogs, toads, salamanders, and newts), invertebrates (like aquatic insects, worms, snails, snakes), small mammals, birds (eggs, chicks), and even plant matter.
They are also fairly “careful” eaters, always rinsing off after each meal.
Human Use: River otters have no significant enemies other than humans. They are occasionally killed unintentionally when tangled in fishing nets or trapped in crab pots. Between 1,200 and 2,400 otters have been caught for their fur in Alaska annually for the past 10 years.
While you may not be able to see these animals frolicking in the wild, be sure to visit your local zoo or wildlife sanctuary. Their noisy antics, dances and games put a smile on everyone’s face.