Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Order Carnivora Bowdich, 1821 - carnivores
       Suborder Caniformia Kretzoi, 1943
         Family Mustelidae Batsch, 1788 - weasels, badgers, skunks, and otters
           Subfamily Lutrinae Bonaparte, 1838 - otters
             Genus Enhydra Fleming, 1822 [monotypic] - sea otter
               Enhydra lutris (Linnaeus, 1758) - sea otter
                 1 [Enhydra lutris lutris] (Linnaeus, 1758) - sea otter
                 2 Enhydra lutris kenyoni Wilson, 1991
                 3 Enhydra lutris nereis (Merriam, 1904) - southern sea otter