Otters have brown fur and often pale on the underside. They have long slender bodies; small ears on a broad head a long thick tail with webbed feet. They swim very low in the water with their head and back barely showing.

About 60-80cm; tail about 32-56cm

Average 8.2 kg for males; 6.0 kg for females.

Origin and Distribution
The otter is a secretive semi-aquatic species which was once widespread in Britain. By the 1970s, otters were restricted mainly to Scotland, especially the islands and the north-west coast, western Wales, parts of East Anglia and the West Country (though they remained common and widespread also in Ireland). This decline was caused by organo-chlorine pesticides. Since these were withdrawn from use, otters have been spreading back into many areas, especially in northern and western England.

General Ecology
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 serve to mark an otter’s range, defending its territory but also helping neighbours keep in social contact with one another. Females with cubs reduce sprainting to avoid detection.

Fish, especially eels and salmonids are eaten, and crayfish at certain times of the year. Coastal otters in Shetland eat bottom-living species such as eelpout, rockling and butterfish. Otters occasionally take water birds such as coots, moorhens and ducks. In the spring, frogs are an important food item.

Up to 10, though few survive more than five years.

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.

Conservation Status
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. Otters require clean rivers with an abundant, varied supply of food and plenty of bank-side 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. Otter populations in England are very fragmented and the animals breed only slowly. Attempts have been made to reintroduce otters to their former haunts, by reintroducing captive bred and rehabilitated animals, with some attempts proving very successful.

Credit: With thanks to The Mammal Society for providing the photo and information. © The Mammal Society