The European Polecat (Mustela putorius) 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 are native to Britain, 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. 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.

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. However, others believe the Berber polecat (M. putorius berberii) to be the ferret's true ancestor.

The word polecat is also used to refer to the skunks of the Americas which belong to the Mephitidae family