Sea Otter
Enhydra lutris
Quick answer
The sea otter is a marine mammal of the North Pacific coast and the smallest marine mammal, famous for floating on its back, using rocks as tools to crack open shellfish, and holding hands while resting. It has the densest fur of any animal, with up to a million hairs per square inch, and is a keystone species that keeps kelp forests healthy. Sea otters typically live 10 to 20 years.
Sea Otter facts at a glance
| Scientific name | Enhydra lutris |
|---|---|
| Diet | Carnivore |
| Habitat | Coastal North Pacific and kelp forests |
| Lifespan | 10–20 years |
| Weight | 14–45 kg (31–99 lb) |
| Top speed | About 9 km/h (5.5 mph) swimming |
| Conservation status | Endangered (IUCN) |
| Kingdom | Animalia |
|---|---|
| Phylum | Chordata |
| Class | Mammalia |
| Order | Carnivora |
| Family | Mustelidae |
| Genus | Enhydra |
Where it lives
Coastal waters of the North Pacific, from California and Alaska to Russia and Japan.
The warmest coat in nature
Unlike whales and seals, sea otters have no insulating blubber. Instead they rely on the densest fur of any animal, with up to a million hairs per square inch, trapping a layer of air to stay warm in cold seas. They spend hours grooming to keep this fur clean and waterproof.
Tool users
Sea otters are one of the few animals that use tools. They often carry a favorite rock in a loose pouch of skin under the forearm and use it to smash open hard-shelled prey such as clams, mussels, and sea urchins while floating on their backs.
Keystone of the kelp forest
By eating sea urchins, otters stop the urchins from overgrazing and destroying kelp forests. Healthy kelp forests shelter countless other species and absorb carbon, which makes the sea otter a keystone species whose presence shapes the whole ecosystem. Otters also hold hands or wrap themselves in kelp to avoid drifting apart while they sleep.
Conservation
Hunted almost to extinction for their fur in the 1700s and 1800s, sea otters have made a partial recovery but remain Endangered. Oil spills, entanglement in fishing gear, and pollution still threaten them, and their loss can trigger the collapse of entire kelp ecosystems.
Frequently asked questions about the Sea Otter
Why do sea otters hold hands?
Sea otters hold hands, or wrap themselves in kelp, while resting so they do not drift apart from one another on the moving water. A group of resting otters is called a raft.
How do sea otters stay warm without blubber?
Sea otters have the densest fur of any animal, up to a million hairs per square inch, which traps a layer of air against the skin for insulation. They groom constantly to keep it working.
Do sea otters really use tools?
Yes. Sea otters use rocks as tools to crack open hard-shelled prey like clams and urchins, often keeping a favorite stone in a skin pouch under the arm.
Why are sea otters important to the ecosystem?
Sea otters are a keystone species. By eating sea urchins, they prevent urchins from destroying kelp forests, which shelter many species and store carbon, so otters keep the whole ecosystem in balance.
Are sea otters endangered?
Yes. After being hunted almost to extinction for their fur, sea otters are listed as Endangered. Oil spills, fishing-gear entanglement, and pollution remain serious threats.
