Enhydra

Enhydra is a genus of aquatic mustelids in the family Mustelidae, commonly associated with sea otters. The living member is Enhydra lutris, the sea otter, and the genus also includes several extinct species known from fossil remains. Taxonomic treatment of subspecies varies by authority, but commonly recognized living subspecies include northern sea otter (Enhydra lutris kenyoni) and southern sea otter (Enhydra lutris lutris or Enhydra lutris nereis).

Habitat and distribution

The sea otter inhabits coastal North Pacific waters from Alaska to central California, with a southern population along the central and southern California coast. They favor nearshore habitats such as kelp forests and rocky shorelines, where they can forage and rest in protected areas.

Physical characteristics and adaptation

Sea otters are among the heaviest fur-bearing marine mammals. They have dense fur for insulation, a compact, stout body, and webbed hind feet. They are skilled divers and use their lungs and underfur to stay submerged while foraging for prey. Their forepaws and sensitive whiskers assist in handling prey and navigating complex coastal habitats.

Diet and foraging

Their diet consists mainly of invertebrates, including sea urchins, clams, mussels, crabs, and snails. They are known for skillful foraging techniques, such as using rocks as anvils to crack hard shells and employing cooperative behaviors in some communities.

Conservation and ecological role

Sea otters play a keystone role in kelp forest ecosystems by regulating herbivore populations that can overgraze kelp. They were driven to near extinction by the fur trade in the 18th and 19th centuries, but recovery has occurred in parts of their range, with ongoing threats including oil spills, fishing gear entanglement, habitat loss, and prey depletion. Fossil records indicate a historically broader diversity within the Enhydra genus.