Enhydra is a genus of mustelid that contains the sea otter and two extinct relatives.

Temporal range: 5–0 Ma
Adult Sea Otter in Morro Bay.jpg
Sea otter (Enhydra lutris)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Subfamily: Lutrinae
Genus: Enhydra
Fleming, 1828

Enhydra lutris - Sea otter
Enhydra macrodonta
Enhydra reevei

Sea otters probably diverged from other otters during the Pliocene, approximately 5 mya.[1] They probably arose from the closely related Enhydritherium.

Enhydra reevesi, the oldest known species, has its origins in the Atlantic, suggesting this may have been where sea otters originated.[1] Fossil evidence indicates the Enhydra lineage became isolated in the North Pacific approximately 2 million years ago, giving rise to the now-extinct Enhydra macrodonta and the modern sea otter.


  1. ^ a b Davis, Randall W. (2019). Marine Mammals: Adaptations for an Aquatic Life. Springer International Publishing. p. 21. ISBN 9783319982809.