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,
Giant otter Pliocene or early Pleistocene. The giant otter shares the South American continent with three of the four members of the New World otter genus "Lontra": the neotropical river otter, the southern river otter, and the marine otter. (The North American river otter ("Lontra canadensis") is the fourth "Lontra" member.) The giant otter seems to have evolved independently of "Lontra" in South America, despite the overlap. The smooth-coated otter ("Lutrogale perspicillata") of Asia may be its closest extant relative; similar behaviour, vocalizations, and skull morphology have been noted. Both species also show strong pair bonding and paternal engagement in rearing cubs.