Otters

Otters are carnivorous mammals in the subfamily Lutrinae of the Mustelidae family. They are aquatic or semi-aquatic and inhabit rivers, lakes, marshes, and coastal seas around much of the world, with notable exceptions such as Australia and Antarctica. There are about 13 extant species, including the North American river otter (Lontra canadensis), the Eurasian otter (Lutra lutra), the Asian small-clawed otter (Aonyx cinereus), the African clawless otter (Aonyx capensis), and the sea otter (Enhydra lutris).

Otters have streamlined bodies, short limbs, and webbed feet. They possess dense, water-repellent fur that provides insulation, since most species lack substantial fat reserves. Their long, muscular tails aid propulsion, and their sensitive whiskers help detect prey in murky water. They can close their ears and nostrils underwater and are accomplished divers, often swimming with efficient, graceful strokes.

Most otters feed mainly on fish, but diets vary by species and habitat and can include crustaceans, mollusks, amphibians, and small vertebrates. They are skilled hunters that typically forage underwater, sometimes using tools; sea otters, in particular, balance rocks on their bellies to break shellfish. Social behavior ranges by species: river otters may form family groups, while sea otters can raft in dense social communities.

Reproduction also varies; most species give birth to litters after a gestation ranging from weeks to months, with pups cared for by one or both parents for several months. Conservation status ranges from least concern to endangered across species. Major threats include habitat loss, water pollution, and entanglement in fishing gear, though protected areas and pollution controls have aided some populations.