Sea otter

Facts about Sea otter

We found 19 facts about Sea otter

Animals nearly extinct due to fur trade

With their playful personalities, adorable faces, and impressive tool skills, sea otters are among the most fascinating and charismatic animals in the world's oceans. Found along the coasts of the North Pacific from Russia to California, these furry marine mammals are known for their unique adaptations to life at sea.

Sea otters are highly social animals that live in groups, called rafts, that can number up to several dozen individuals. These rafts typically consist of females and their pups, with a few males present to breed. Within the raft, sea otters communicate with each other using a variety of vocalizations, including chirps, whistles, and growls.

They play a key role in protecting coastal ecosystems by consuming excessive numbers of herbivore species, such as sea urchins, which destroy kelp forests that are vital to many marine organisms.

The species nearly disappeared from the face of the earth as the fur trade, which began to develop in the second half of the 18th century, reduced the population from several hundred thousand to just two thousand in 150 years.

Read on to find out more about these little marine mammals.

Sea otter
Sea otters (Enhydra lutris) are the smallest marine mammals in the world. We distinguish three subspecies: Asian sea otter, northern sea otter, and southern sea otter.

The largest subspecies is the Asian sea otter, which lives in the northwestern Pacific Ocean. The southern sea otter, which lives along the central and southern California coast, is the smallest.

Despite being the smallest marine mammal, sea otters are the largest of all mustelids.

The Mustelidae family includes about 70 different species such as badgers, weasels, otters, and polecats.

Males are larger, usually weighing between 22 and 45 kg, but individuals weighing 54 kg have been reported.

Females weigh about ⅓ less. The length of an adult male can vary from 1.2 to 1.5 m, while females rarely reach 1.4 m.

They have the densest fur of any animal.

Sea otters grow about 150,000 hairs per 1 cm2 (about 1 million per 1 square inch). It is made up of two types of hair: underfur and guard hairs, which are waterproof and protect the underfur from soaking.

Between the coat and the skin is an air space that helps otters keep their bodies warm. This is why sea otters do not have blubber, which is common in many marine animals.

They forage on the bottom of coastal waters.

Their main food is clams and mussels, but they can also hunt squid, octopus and fish. In general, over 100 species make up their menu.

They are great divers and are capable of going for up to five minutes without breathing.

Sea otters usually do not need to dive for that long, as they live in shallow water down to 23 m (75 ft).

To maintain body temperature, sea otters need to consume at least 25% of their body weight a day.
When swimming, they can reach speeds of up to 9 km/h. They are very good swimmers but do not venture into open water.

 They are typically found up to 1 km (0.62 mi) from shore, where they can find cover among barrier reefs, rocks, and kelp forests.

An individual may spend its entire life in the water, but many venture onto land.

In contrast to the water environment, sea otters are very clumsy on land, but this does not stop them from taking a rest on land. 

Sea otters are known to use rocks as tools.

They dive for stones, select the most suitable one, and use it to crush the shells of their prey (such as clams or mussels). Stones are not only used for food, but also for grooming and cleaning their fur.

They are polygynous, males have several female partners.

Their gestation period can vary greatly. It can last from four months to a year after copulation. This is due to delayed implantation, a strategy that allows the fertilized egg not to implant in the uterus immediately after fertilization, but to enter a pause (diapause) for a while before it starts to develop further.

This strategy allows the mother to time the birth of her offspring with the most advantageous conditions for survival.

The female gives birth to one pup that weighs 1.4 to 2.3 kg (3 to 5 lbs).

Twins are very rare, occurring in only about 2% of all births. It is even less likely that both pups will survive.

They play a critical role in maintaining their ecosystem.

Species that (even in small numbers) have such a large positive impact on their environment are called keystone species. Sea otters consume excessive amounts of benthic herbivores (such as clams, mussels, or snails), which can damage kelp forests that are critical to coastal marine biodiversity.

They are prey to many animals both on land and in the water.

Major predators of sea otters are: great white sharks, killer whales, bald eagles, gulls, crows, coyotes and wolves.

The greatest threat to sea otters is human activity. Although it is illegal today, sea otters were once hunted in large numbers for their pelts. Massive fur hunting began in the 18th century.

The species was saved by the enforcement of a Treaty for the Preservation and Protection of Fur Seals, signed by the United States, Russia, Japan, and Great Britain in 1911. It is estimated that when the treaty was signed, there were only about 1,000 to 2,000 otters left alive in the wild.

At least one million sea otters were killed before the hunting ban was imposed.
Today, it is illegal to hunt sea otters, but the species is still threatened by human activities such as oil spills, pollution, and habitat degradation. 

Of all the threats, oil spills are the most deadly to sea otters, as contact with oil makes the otters' fur soak with water, leading to hypothermia.

They remain an endangered species. 

Their current global population is estimated at about 110,000 individuals, which is still much lower than before the 1740s, when the fur trade began on a massive scale. In addition, populations in the Aleutian Islands and California have declined in recent years and have not yet recovered.

In the wild, they typically live from 10 to 20 years, while females tend to live 5 years longer than males.

Maximum recorded life span of sea otter is 23 years in the wild. The longest-lived specimen in captivity was 28 years old female.

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