Otter Otter Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the weasel family Mustelidae, which also includes badgers, honey badgers, martens, minks, polecats, and wolverines. The word "otter" derives from the Old English word "otor" or "oter". This, and cognate words in other Indo-European languages, ultimately stem from the Proto-Indo-European language root *wódr̥, which also gave rise to the English word "water". An otter's den is called a holt or couch. Male otters are called dogs or boars,
Sea otter remains classified as an endangered species. The sea otter is the heaviest (the giant otter is longer, but significantly slimmer) member of the family Mustelidae, a diverse group that includes the 13 otter species and terrestrial animals such as weasels, badgers, and minks. It is unique among the mustelids in not making or burrows, in having no functional anal scent glands, and in being able to live its entire life without leaving the water. The only member of the genus "Enhydra", the sea otter is so different from other mustelid species that, as recently as 1982, some scientists believed it