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 may aggressively charge intruders, including boats with humans in them. The longest documented giant otter lifespan in the wild is eight years. In captivity, this may increase to 17, with an unconfirmed record of 19. The animal is susceptible to a variety of diseases, including canine parvovirus. Parasites, such as the larvae of flies and a variety of intestinal worms, also afflict the giant otter. Other causes of death include accidents, gastroenteritis, infanticide, and epileptic seizures. The giant otter is an apex predator, and its population status reflects the overall health of riverine ecosystems. It feeds mainly on fish, including