Otter

Otters are carnivorous mammals belonging to the subfamily Lutrinae. This group is a branch of the Mustelidae family. This family also includes animals like weasels, badgers, minks, and wolverines. There are 14 known extant species of otters living today. These species are semiaquatic, meaning they live in both freshwater and marine environments.

Because they live in water, otters have developed unique physical traits. They possess long, slim bodies and relatively short limbs. Their most important tools for swimming are their powerful webbed feet. Most species also have sharp claws on their feet. All otters except the sea otter have long, muscular tails to help them move.

To survive in wet environments, otters rely on a very specialized coat. Their fur consists of a soft, insulated underfur. This is protected by an outer layer of long guard hairs. This structure works like a trap for air. The trapped air keeps the otter dry and warm while underwater. It also provides buoyancy, which helps the animal float.

Some species live in very cold waters. These otters must maintain a high metabolic rate to stay warm. For example, Eurasian otters must eat 15% of their body weight every day. Sea otters have even higher needs. They may eat 20% to 25% of their body weight daily. In water as warm as 15°C, a sea otter must catch 25% of its body weight in fish every hour to survive.

An otter's diet is mostly made up of fish. However, many species also eat frogs, birds, or crayfish. Some otters are experts at eating shellfish like crabs. Sea otters are different because they focus on clams and sea urchins. They have a unique way of eating these shelled creatures. They use stones to break the shells open against their bellies. This is a learned skill that young otters must practice.

Because they depend so much on specific prey, otters are vulnerable. If the prey disappears, the otter population suffers. Most species hunt for three to five hours each day. Nursing mothers must work much harder, often hunting for up to eight hours a day.

Otters have a specific life cycle and social structure. A female otter is called a bitch or a sow. A male is called a dog or a boar. Their offspring are known as pups or cubs.

Female otters reach sexual maturity at about two years of age. Males reach maturity at approximately three years. The gestation period, or the time a mother carries her young, lasts 60 to 86 days. Once born, the pup is cared for by the mother and older offspring. A pup can leave its den after one month. By two months, the pup can swim. They typically stay with their family for about one year. Otters can live up to 16 years in the wild.

Otters live in dens called holts or couches. These are often built under tree roots or rocky cairns. Many otters line these homes with moss and grass. Socially, otters vary by species. Some are solitary animals that live alone. Others live in groups, which can sometimes be quite large. When otters are together in the water, they are called a raft. On land, a group might be called a bevy, a family, a lodge, or a romp.

They are known to be playful, sometimes sliding down natural dirt slides into the water.

Humans have had a complex relationship with otters throughout history. Since at least the 1700s, otters have been hunted for their pelts. In China, royalty and wealthy people wore robes made from otter fur. In some places, otter tails were used for hats and belts. In England and Wales, otter hunts were once common. Between 1958 and 1963, 11 hunts killed 1,065 otters.

In southern Bangladesh, people have a different relationship with them. For generations, fishermen there have used smooth-coated otters to help drive fish into nets. While rare, otters can occasionally attack humans if they feel provoked. A 2011 review found 42 reported attacks between 1875 and 2010, mostly involving the North American river otter.

Otters also appear frequently in human culture and mythology. In Norse mythology, a dwarf named Ótr often took the form of an otter. In Japanese folklore, otters called "kawauso" are known as shapeshifters. They are said to change into beautiful women or children to trick people.

In Native American cultures, the otter is often a totem animal. In Korean mythology, seeing an otter might mean you will attract rain clouds. These stories show how much people have observed and wondered about these animals for centuries.