The ferret (Mustela furo) is a small, domesticated species belonging to the family Mustelidae. The ferret is most likely a domesticated form of the wild European polecat (Mustela putorius), as evidenced by the ferret's ability to interbreed with European polecats and produce hybrid offspring. Physically, ferrets resemble other mustelids because of their long, slender bodies. Including their tail, the average length of a ferret is about 50 cm (20 in); they weigh between 0.7 and 2.0 kg (1.5 and 4.4 lb); and their fur can be black, brown, white, or a mixture of those colours. The species is sexually dimorphic, with males being considerably larger than females.
In common with most domestic animals, the original reason for ferrets being domesticated by human beings is uncertain, but it may have involved hunting. According to phylogenetic studies, the ferret was domesticated from the European polecat (Mustela putorius), and likely descends from a North African lineage of the species. Analysis of mitochondrial DNA suggests that ferrets were domesticated around 2,500 years ago. It has been claimed that the ancient Egyptians were the first to domesticate ferrets, but as no mummified remains of a ferret have yet been found, nor any hieroglyph of a ferret, and no polecat now occurs wild in the area, that idea seems unlikely.The American Society of Mammalogists classifies M. furo as a distinct species.