The Otter ,Lutra lutra is Britain’s largest member of the Weasel Family , leading an amphibious lifestyle in our rivers, lakes and river estuaries. By the 1960s they were on the verge of extinction due to river pollution, habitat loss and hunting. Now with legal protection, cleaner rivers and managed habitat it is returning to former haunts with a slow but steady population growth. Seeing the signs of otters is far easier than seeing the animals themselves. Along riverbanks and waterways, look for five-toed footprints (about 6-7cm long) and droppings or ‘spraints’. Otters leave spraints in prominent places, such as fallen trees, weirs and bridges, as ‘scented messages’, helping them to find mates and defend territories. They contain visible fish bones and have a distinctive, smell.
The otter is the largest member of the weasel family.
The male otter ( dog ) and the female ( bitch ) have large lungs and can stay submerged under water for 4 minutes, often swimming 400 metres before resurfacing. They can reach speeds of 10 miles per hour under water and can easily out run a man on land. Otters can have up to one million hairs per square inch. There are two layers of fur—an undercoat and then longer hairs that we can see. The layers manage to trap air next to the otter’s skin, which keeps the otters dry and warm and also helps with buoyancy. Otter pups have so much air trapped in there, they actually can’t dive under water, even if they want to.
Otters have a good sense of smell, and they are actually capable of smelling things underwater.
The males occupy large ranges, which may include up to 20 km of river bank and daily travel long distances along regular routes by the margins of the river. The young or cubs are normally born in the spring and arrive in the world blind and dependant on their mother, suckling for up to 6 months. The mother normally cares for the cubs alone, living in a nest or holt , lined with grass and bedding. After about a month, the pups will open their eyes and start to explore the den, and at about two months, the pups will learn to swim. They with their mother and siblings until they are about one year old, when they head off on their own. Otters reach maturity at 2 to 5 years old depending on the species.. Otter families are usually limited to pups and their mothers, and these family groups will spend most of their time either feeding or sleeping.
Fish, especially eels and salmonids are eaten, along with 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 become an important food source . Otters normally take their prey to land to eat. A daily food intake of 15–20% of body weight is key to survival, and otters adapt their patterns of predation and hunting behaviour to make the most of the prey available during these leaner months.
The average lifespan: of the Otter is up to 10 years
Otters are 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. Marshes are 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 in numbers . Otter populations in England are very fragmented and the animals breed only slowly.
Size: Head/body length: 60 – 120 cm; tail 40 – 45 cm. Dogs 8kg Bitches 6kg
Description: Brown fur, often pale underside, long slender streamlined body, small ears, long thick tail and webbed feet.
Habitat: Found on coasts and estuaries and in fresh water habitats with suitable cover.
Young: 3 ‘cubs’ can be born at any time of the year but usually in early spring .
Nest: The holts are usually burrowed into stream banks with an underwater entrance.
Diet: Fish, eels, crustaceans, rabbits, small mammals , frogs and ducks.
Population: Estimated to be 15,000.
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