The floating kelp forest caretaker
The Sea Otter (Enhydra lutris) is a charismatic marine mammal known for floating on its back, using tools, and keeping kelp forest ecosystems in balance. Wrapped in the densest fur of any mammal, sea otters spend nearly their entire lives in the ocean.
These playful hunters dive for urchins, crabs, clams, mussels, and other invertebrates. By feeding on sea urchins, they help protect kelp forests from overgrazing.
Key facts
- Scientific name
- Enhydra lutris
- Native region
- Coastal waters of the North Pacific, including California, Alaska, Russia, and parts of Japan
- Notable trait
- Dense waterproof fur and tool use for cracking open shellfish
- Diet
- Sea urchins, crabs, clams, mussels, snails, and other marine invertebrates
- Size
- Adults are usually 4 to 5 feet long
- Lifespan
- Often 10 to 20 years in the wild
Habitat
Sea otters live in nearshore coastal waters, especially around kelp forests, rocky reefs, bays, and protected coves. They rarely travel far from shore and depend on rich shallow habitats for food and shelter.
Kelp forests offer cover, feeding grounds, and places to rest. Sea otters often wrap themselves in kelp while floating so they do not drift away while sleeping.
Behavior
Sea otters are skilled divers and foragers. They search the seafloor for prey, often carrying food and a favorite rock back to the surface in loose skin folds under their arms.
At the surface, they float on their backs and use stones to crack open hard shelled prey like clams and mussels. This tool use is one of their most famous behaviors.
They spend a lot of time grooming. Clean fur traps air and keeps them warm in cold ocean water, since sea otters do not have the thick blubber layer found in many other marine mammals.
FAQs
Why do sea otters float on their backs?
Floating on their backs lets sea otters rest, groom, eat, and handle prey at the surface.
Do sea otters use tools?
Yes. Sea otters often use rocks to crack open clams, mussels, and other hard shelled prey.
Why are sea otters important to kelp forests?
Sea otters eat sea urchins, which helps prevent urchins from overgrazing kelp and damaging kelp forest habitat.
Do sea otters have blubber?
No. Unlike many marine mammals, sea otters rely on dense fur and constant grooming to stay warm.
Are sea otters endangered?
Some sea otter populations are still threatened or endangered. They face risks from oil spills, disease, habitat changes, and conflicts with fishing gear.
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