Brown fur, often pale on underside; long slender body; small ears; long thick tail; webbed feet
Head/body length: about 60-120cm; tail about 40-45cm
Weight: average 10.1 kg for males; 7.0 kg for females.
A secretive semi-aquatic species which was once widespread in Britain. Today, otters are restricted mainly to Scotland, especially the islands and the north-west coast, Wales, parts of East Anglia and the West Country. However there are signs that otters are spreading in some areas. Otters live along rivers, lakes and sea coasts, and, at times, in marshy areas some distance from open water. Coast-living otters need fresh water to clean salt from their fur, otherwise this will lose its ability to keep them warm. With the exception of parts of the West coast of Scotland, otters are generally nocturnal.
Fish are the otter's most important food. Coarse fish, eels and salmonids are eaten, depending on what is present. Coastal otters in Shetland eat bottom-living species such as eelpout, rockling and butter fish. Otters may also take water birds such as coots, moorhens and ducks. In the spring, frogs are an important food item.
Otters can travel over large areas. Some are known to use 20 kilometres or more of river habitat. Otters deposit faeces (known as spraints, with a characteristic sweet musky odour) in prominent places around their ranges. These probably serve to mark an otter's range and help neighbouring animals keep in social contact with one another.
In England and Wales otter cubs, usually in litters of two or three, can be born at any time of the year. In Shetland and North-west Scotland most births occur in summer. Cubs are normally born in dens, called holts, which can be in a tree root system, a hole in a bank or under a pile of rocks. About 10 weeks elapse before cubs venture out of the holt with their mother, who raises the cubs without help from the male. Initially females catch food for their cubs, who remain with her for about a year. Otters can live to be ten years old, though few survive more than five years.
Otters are strictly protected by the Wildlife and Countryside Act (1981) and cannot be killed, kept or sold (even stuffed specimens) except under licence.
In the late 1950s and early 1960s otters underwent a sudden and catastrophic decline throughout much of Britain and Europe. The cause was probably the combined effects of pollution and habitat destruction, particularly the drainage of wet areas. Persistent organochlorine pesticides, which otters accumulate in their bodies because they are at the top of the food chain, were in widespread use at the time.
Otters require clean rivers with an abundant, varied supply of food and plenty of bankside vegetation offering secluded sites for their holts. Riversides often lack the appropriate cover for otters to lie up during the day. Such areas can be made more attractive to otters by establishing "otter havens", where river banks are planted-up and kept free from human disturbance. Marshes may also be very important habitat, for raising young and as a source of frogs.
While otters completely disappeared from the rivers of most of central and southern England in just 50 years, their future now looks much brighter. There is evidence that in certain parts of the UK the otter is extending its range and may be increasing locally. However there is no room for complacency. Otter populations in England are very fragmented and the animals breed only slowly.
Attempts have been made to bring otters back to their former haunts, by reintroducing captive bred and rehabilitated animals to the wild. These reintroductions are not easy, but have been very successful is some cases.
What can I do to help otter conservation?
Contact your local Wildlife Trust, they may be involved in conservation work on otters.
Where can I see otters?
There are very few places where you can regularly watch otters in the wild, apart from Shetland and the West coast of Scotland. However, several wildlife parks keep otters. The Otter Trust has sites at Earsham, near Bungay, Suffolk and at North Petherwin near Launceston, Cornwall. The Chestnut Centre, near Chapel-en-le-Frith, Derbyshire, also has otters.
Woodroffe, G.L. (1994) The Otter. The Mammal Society, London.
Chanin, P. (1993) Otters. Whittet Books, London.
Corbet, G.B. & Harris, S. (1991) The Handbook of British Mammals. (3rd edn.). Blackwell, Oxford.
Morris P.A. (1993) A Red Data Book for British Mammals. The Mammal Society, London.
Morris, P.A. (editor) (1992) Proceedings of the National Otter Conference, September 1992. The Mammal Society, London.