Sea otters are small, charismatic marine mammals that inhabit the coastal waters of the eastern and northern North Pacific Ocean. They are known for their playful behavior, endearing faces, and remarkable intelligence.
Beyond their adorable appearance, sea otters play a vital role in maintaining the health of marine ecosystems by controlling populations of invertebrates that can damage kelp forests.
In this article, we’ll explore the fascinating world of sea otters, including their unique characteristics, habitat, diet, reproduction, and more.
Appearance
Sea otters are small marine mammals, measuring 40–65 inches long and body weight of 16–40 kg (35–90 pounds) when fully grown. Their streamlined body shape with a round head, small ears, and large, expressive eyes also stand out.
Sea otters have the thickest fur of any animal, with up to a million hair strands per square inch. This luxurious coat, which ranges from dark brown to lighter shades of gray or tan, helps keep them warm in cold ocean waters since they lack the insulating blubber found in other marine mammals.
Besides, these wonderful creatures are popular for their short, sturdy legs with webbed feet. Sea otters also have tails that they use with incredible ease to propel themselves through the water.
Did you know…
When sea otters dive underwater, their nostrils and ears automatically close to keep water out, ensuring they can focus on hunting or exploring without discomfort. This adaptation allows them to stay submerged for several minutes while searching for food.
Habitat
Sea otters inhabit the shallow coastal waters of the North Pacific Ocean, stretching from northern Japan and Russia’s Kuril Islands across the Bering Sea to Alaska and down the west coast of North America to California coast.
They thrive in nearshore environments such as kelp forests, rocky coastlines, bays, and estuaries. Kelp forests provide both food and shelter, with otters using the kelp to anchor themselves while resting or grooming. Bays and estuaries provide calmer waters and diverse food sources, making them ideal habitats, especially for mothers with pups.
Sea otters typically stay within a few miles of the coastline, preferring shallow waters less than 100 feet deep and rarely venturing into the open ocean.
Diet
Sea otters eat both plants and animals. However, their diet consists mostly of marine invertebrates such as clams, mollusks and crustaceans, mussels, crabs, sea urchins, and some fish species.
Sea otters can also eat fish and other small marine animals.
To forage for food, they use their forepaws instead of teeth, which other marine mammals use.
Reproduction
Sea otters have a strong social bond and are known to hold hands while they sleep to stay together. Males have several female partners that are often members of their friendly social groupings.
Male sea otters can be aggressive when it comes to mating. They typically grasp the female, bite down on her nose, and hold on. This often results in a few injuries.
Sea otters can have a pup at any time of the year. Southern sea otters breed and pup year-round, while northern sea otter pups in Alaska are usually born in the spring. Mothers leave their pups safely floating on the water’s surface while they forage for food.
Females give birth to a single pup after a gestation period of between four and 12 months. Pups are born weighing around 1.4 to 2.3 kilograms, and twins occur in 2% of births. The young ones are completely dependent on their mothers for survival.
The nursing of California sea otters lasts between six and eight months. It lasts for twelve months in the Alaskan population.
Threats
Sea otter populations are vulnerable to several threats, including habitat loss, risk of oil spills, entanglement, boat strikes, diseases, ocean acidification, and predation by killer sharks, especially in the North, and whales.
They are also at risk of being caught in fishing gear, which can lead to injury or death. In addition, sea otters face competition for food and habitat from other marine species.
10 More Amazing Facts About Sea Otter
- Sea otters have the densest fur of any mammal, with up to 1 million hairs per square inch.
- They can delay implantation for up to eight months.
- An otter pup’s fur is so dense that it can’t dive underwater until it gets its adult fur.
- They are excellent swimmers and divers and can hold their breath for up to 5 minutes.
- They use tools like rocks to help them open food sources like shellfish, clams, and mussels.
- They are social animals and often live in groups called rafts.
- Sea otters play an important role in their ecosystem by eating marine invertebrates that can harm kelp forests.
- They were nearly hunted to extinction for their valuable fur, but their populations have recovered thanks to conservation efforts.
- Their whiskers help them detect prey underwater.
- The southern sea otter is the smallest marine mammal.
FAQs
Why are sea otters going extinct?
Sea otters are classified as endangered by the International Union for Conservation of Nature (IUCN) and are protected under the Marine Mammal Protection Act and the Endangered species act in the United States in the 1970s. They are at risk of extinction due to various factors, including habitat destruction, pollution, and hunting.
Are sea otters aggressive?
They are generally not aggressive marine mammals. They are known for their social and playful behavior and are often described as being curious and friendly. However, like any animal, sea otters can become aggressive if they feel threatened or if their territory is invaded. Male sea otters can also be aggressive during mating.
How long can a sea otter hold its breath?
Sea otters are adapted to live in the water and can hold their breath for extended periods. The length of time that an otter can hold its breath depends on various factors, including the age and size of the individual and the activity they are engaged in at different times.
Most scientists believe that Sea otters can hold their breath for up to 5 minutes.
What is the difference between a sea otter and a river otter?
Sea otters and river otters differ in size, habitat, and behavior. Sea otters are larger and inhabit coastal marine environments, using tools and often floating on their backs. River otters are smaller, prefer freshwater habitats, and are more active swimmers and divers.
