Otter ( Christopher Otter )

Otters are aquatic or marine carnivorous mammals, members of the large and diverse family Mustelidae, which also includes weasels, polecats, badgers, and others. There are 13 species of otter in 7 genera, with a distribution that is almost worldwide.

A group of otters is called a romp.

Physical characteristics

Otters have a dense layer (1,000 hairs/mm², 650,000 hairs per sq. in) of very soft underfur which, protected by their outer layer of long guard hairs, keeps them dry under water and traps a layer of air to keep them warm. Unlike most marine mammals (seals, for example, or whales), otters do not have a layer of insulating blubber.

All otters have long, slim, streamlined bodies of extraordinary grace and flexibility, and short limbs; in most cases the paws are webbed. Most have sharp claws to grasp prey but the short-clawed otter of southern Asia has just vestigial claws, and two closely related species of African otter have no claws at all: these species live in the often muddy rivers of Africa and Asia and locate their prey by touch.

Diet

Fish is the primary item in the diet of most otters, supplemented by frogs, crayfish, and crabs; some have become expert at opening shellfish, and others will take any small mammals or birds that happen to be available. To survive in the cold waters where many otters live, the specialised fur is not enough: otters have very high metabolic rates and burn up energy at a profligate pace: Eurasian otters, for example, must eat 15% of their body weight a day; sea otters, 20 to 25%, depending on the temperature. In consequence, otters are very vulnerable to prey depletion. In water as warm as 10°C an otter needs to catch 100 g of fish per hour: less than that and it cannot survive. Most species hunt for 3 to 5 hours a day, nursing mothers up to 8 hours a day.

Species

Northern River Otter

Main articles: northern river otter,

The northern river otter (Lontra canadensis) was one of the major animals hunted and trapped for fur in North America after contact with Europeans. They are one of the most playful and active, making them a popular exhibit in zoos and aquaria, but unwelcome on agricultural land because they alter river banks for access, sliding, and defense. River otters eat a variety of fish and shellfish, as well as small land mammals and birds. They are 1 m (3 to 4 feet) in length and weigh from 5 to 15 kg (10 to 30 pounds). They were once found all over North America, but are rare or extinct in most places, although flourishing in some locations.

Otters are a protected species in some areas and some places have otter sanctuaries. These sanctuaries help ill and injured otters to recover.

European Otter

Otters are also found in Europe. In the United Kingdom they were common as recently as the 1950s, but are now rare due to the former use of chlorinated hydrocarbon pesticides and as a result of habitat loss. Numbers reached a low point in the 1980s, but with the aid of a number of initiatives, by 1999 numbers were estimated to have recovered to just below 1,000 animals. Under the UK Biodiversity Action Plan it is hoped that by 2010 the otter will have been reintroduced to all the UK rivers and coastal areas that it inhabited in 1960. Roadkill deaths are now one of the significant threats to their reintroduction.