Lutra lutra; The Otter (River Dog, or Dratsie)
The otter is the largest in size of the family, though sometimes weighs less than the badger. It has a broad muzzle, tiny ears with webbed feet and a long muscular tail known as a rudder which helps it to hunt underwater; it is the only true riparian carnivore in the UK, though both polecats (Mustela putorius) and mink (Neovison vison) are known to hunt in streams on occasion. Historically, the otter declined sharply in numbers not just in the UK but throughout its range due to organochlorides such as DDT, and otter hunting would not have helped the situation either. DDT and otter hunting were both outlawed decades ago, but the otter is still classed as 'near threatened' according to the International Union for the Conservation of Nature (IUCN), though it has now returned to every county in the UK. They are primarily hunters of fish, and historically the eel was the main food source, which is now critically endangered; other food sources include crustaceans, amphibians, small mammals and birds such as coots (Fulica atra) and moorhens (Gallinula chloropus). Their homes are known as holts, with males called 'dogs', females 'bitches' and juveniles 'pups', and the term otter is thought to originate from the Greek for 'water snake' (Dratsie is only a term used in Scotland). In Cheshire, they are present on the Biodiversity Action Plan (BAP) and so their presence is welcomed by many.