The first scientific description of the sea otter is contained in the field notes of Georg Steller from 1751, and the species was described by Linnaeus in his Systema Naturae of 1758.[5] Originally named Lutra marina, it underwent numerous name changes before being accepted as Enhydra lutris in 1922.[6] The generic name Enhydra, derives from the Ancient Greek en/εν "in" and hydra/ύδρα "water",[7] meaning "in the water", and the Latin word lutris, meaning "otter".[8]
The sea otter was formerly sometimes referred to as the "sea beaver",[9] being the marine fur-bearer similar in commercial value to the terrestrial beaver. Rodents (of which the beaver is one) are not closely related to otters, which are carnivores. It is not to be confused with the marine otter, a rare otter species native to the southern west coast of South America. A number of other otter species, while predominantly living in fresh water, are commonly found in marine coastal habitats. The extinct sea mink of northeast North America is another mustelid that had adapted to a marine environment.