The European Polecat (Mustela putorius), also known as a fitch, is a member of the Mustelidae family, and is related to the stoats, otters, weasels, and minks. They are dark brown with a lighter bandit-like mask across the face, pale yellow underbody fur, a long tail and short legs. They are somewhat larger than weasels, weighing between 0.7 kg for females to 1.7 kg for males, but smaller than otters.

Polecats live in most of the countries of Europe. They are mainly nocturnal and usually found in woodlands, farmlands, and wetlands. They often make dens in stream banks or under tree roots. Mainly carnivorous, they feed largely on frogs and voles, but will also catch rats and other small prey. They require a home range of about a square kilometer. The pattern of polecat predation on frogs was found to be sex selective and predation by polecats is found to influence sex ratio, male abundance and sexual conflict in a frog mating system, restricting the opportunity for multiple mating. Polecats (mainly dark phenotype) are able to hybridize with the rare European mink and have fertile hybrids. In some parts of England, the abandoning of domestic ferrets has led to ferret-polecat hybrids living in the wild that are almost indistinguishable from pure polecats. Although Polecats were chiefly polygynous, but females could show polyandry and, related to sexual conflict, the mating system could change with environmental conditions.

Other species of polecat include the Steppe Polecat (M. eversmanni) and the European Mink (M. lutreola). Most zoologists believe that the domestic ferret (M. putorius furo) is descended from the European Polecat, or possibly from a hybrid of the European and steppe varieties. The Zorilla, also called the striped polecat (Ictonyx striatus), lives in subsaharan Africa.