The ferret (Mustela putorius furo) is the domesticated form of the European Polecat, a mammal belonging to the weasel genus of the family Mustelidae. They typically have brown, black, white, or mixed fur. They have an average length of 51 cm including a 13 cm tail, weigh about 0.7–2 kg, and have a natural lifespan of 7 to 10 years. Ferrets are sexually dimorphic predators with males being substantially larger than females.