Heads of a 1) polecat, 2) ferret and 3) polecat-ferret hybrid
A Polecat-Ferret hybrid is a cross between a European polecat (Mustela putorius) and a ferret (Mustela putorius furo). Crossbreeds between the two animals typically have a distinct white throat patch, white feet and white hairs interspersed among the fur.
Typically, first-generation crossbreeds between polecats and ferrets develop their wild parent's fear of humans if left with their mother during the critical socialisation period between 7½ and 8½ weeks of age. It is currently impossible to distinguish pure polecats from hybrids through DNA analysis, as the two forms are too closely related and inter-mixed to be separated through modern genetic methods.
In some parts of Britain, the escape of domestic ferrets has led to ferret-polecat crossbreeds living in the wild. Ferrets were likely first brought to Britain after the Norman conquest of England (in the 11th century) or as late as the 14th century.John George Wood wrote that polecat-ferrets were sometimes used by hunters alongside pure ferrets. In modern times, supposed ferret-polecat crossbreeds are occasionally advertised as superior to pure ferrets for the purposes of rabbiting, though actual crossbreeds are very likely to be less handleable, less willing to familiarise themselves with dogs, and are more likely to kill their quarry outright rather than simply flush it from its burrow. The advantages of polecat-ferret hybrids over pure ferrets include the hybrid's better eyesight, their greater physical capabilities and their more independent nature. The disadvantages are that hybrids are less willing to be handled, require rigorous enrichment routines in order to prevent boredom, refuse to enter unfamiliar holes and do not cope well with being caged.