Otters are semi-aquatic (or in one case aquatic) fish-eating mammals. The otter subfamily Lutrinae forms part of the family
Mustelidae, which also includes weasels, polecats, badgers, as well as others. With thirteen species in seven genera, otters
have an almost worldwide distribution. They mainly eat aquatic animals, predominantly fish and shellfish, but also other invertebrates,
amphibians, birds and small mammals. The word otter derives from the Old English word otor or oter.