The European River Otter's scientific name is Lutra lutra, which means "otter otter".  It belong to the weasel family, Mustelidae, which they share with minks and weasels.

European river otters range in length from 3 to 3.5 feet and weigh between 12 and 26 pounds. Their fur is brownish-gray with their throats being a buff or cream color. These otters range south of the Arctic Circle throughout Europe, most of Asia, and parts of northern Africa. The individuals in Asia tend to have a lighter overall color than those in Europe. The life expectancy of the European river otter is ten years.

The European river otter has an extensive range. They inhabit a variety of habitats from rivers and streams to lakes, ponds, and marshes. Some individuals can be found in coastal waters, but they are not specially adapted to handle a marine environment. They require a nearby source of fresh water for drinking and grooming. The large geographic region in which these animals may be found, however, is not a reflection of population size. They are considered a vulnerable species and have become extinct across much of their range. Like most otter species, they are highly opportunistic predators. Their primary source of food is fish, but they will also eat small crustaceans, frogs, and small birds or mammals when those prey items are plentiful.

This species of otter is nocturnal, and begins becoming active at dusk. They are solitary animals in adulthood, and they will display territorial aggression to otters of the same sex. A male’s territory will overlap that of several females. It is interesting to note that the European river otter does not have a particular breeding season. Kits are born after a gestation period of around 63 days; the typical litter has 2 or 3 kits. Young usually leave their mother between 8 and 12 months of age, although there are rare instances in which they remain for 14 months.

In the past, the European river otter was often mistakenly considered a pest for local fisheries. People later learned that the otters actually preferred slow-swimming fish species that were not used for human consumption. This misunderstanding did take a serious toll on their population, as did the fur trade, and their numbers declined rapidly. Today, the European river otter is protected by the European Protection of Wildlife and Living Habitats Agreement, which was enacted in 1979. This act strictly prohibits the hunting, capture, and trade of otters within their European range. The animals still face many threats from other human sources, and there are currently several studies looking into ways to clean up polluted habitats.