Sea otters (*Enhydra lutris*) are charismatic marine mammals known for their playful behavior, thick fur, and crucial ecological role. Found along the northern Pacific Rim, from Japan and Russia to Alaska and down the coasts of Canada and California, these animals thrive in cold coastal waters where kelp forests and rocky shorelines provide both food and shelter.
One of the most remarkable features of sea otters is their fur—the densest in the animal kingdom. Unlike most marine mammals, sea otters do not rely on a thick layer of blubber for warmth. Instead, their fur traps air and provides insulation. To maintain its effectiveness, sea otters spend hours grooming each day, ensuring their coat remains clean, waterproof, and buoyant. This meticulous grooming behavior is not only essential for survival but also gives them their well-known fluffy appearance.
Sea otters are highly skilled hunters and tool users. They feed on a variety of marine invertebrates, including sea urchins, crabs, clams, and snails. To crack open hard-shelled prey, they often use rocks as tools—one of the few examples of tool use in the animal kingdom. By controlling sea urchin populations, otters indirectly protect kelp forests from overgrazing. This predator-prey balance is vital: kelp forests provide food, shelter, and carbon storage, supporting diverse marine ecosystems. Without otters, many kelp ecosystems collapse into barren “urchin barrens.” For this reason, sea otters are considered a keystone species.
Socially, sea otters can be both solitary and social. Females are often seen floating with pups, while males may gather in loose groups. Larger groups, called “rafts,” sometimes form, with dozens or even hundreds of otters resting together at the surface. Pups, born with buoyant fur, cannot dive at first. Mothers wrap them in kelp to prevent them from drifting while they forage. The strong maternal bond is a hallmark of sea otter behavior, with mothers investing heavily in teaching their young to swim, groom, and hunt.
Historically, sea otters were hunted to near extinction during the fur trade of the 18th and 19th centuries. Their luxurious pelts were highly prized, reducing populations from an estimated several hundred thousand to fewer than 2,000 individuals. Conservation efforts, including international protections and reintroduction programs, have helped populations rebound in many areas, though challenges remain. Today, threats include oil spills, habitat loss, pollution, climate change, and predation by orcas.
Beyond their ecological role, sea otters capture human admiration for their intelligence and charm. Watching them float on their backs, cracking shells or holding paws in “rafts,” highlights their blend of practicality and playfulness. Yet, their story is also a reminder of the fragility of marine ecosystems and the importance of conservation.
In many coastal regions, the return of sea otters has signaled the recovery of marine ecosystems, making them not just a species worth protecting, but also a symbol of resilience and the interconnectedness of life beneath the waves.