European Polecat - Hybridisation

Hybridisation

In some parts of the British Isles, the abandoning 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, or as late as the fourteenth century. It is currently impossible to distinguish pure polecats from hybrids through DNA analysis, as the two forms are too closely related and intermixed to be separated through modern genetic methods. 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 parents' fear of humans if left with their mothers during the critical socialisation period between 7½ and 8½ weeks of age. Occasionally, supposed ferret-polecat crossbreeds are 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.

Polecats are able to hybridise with the rare European mink, producing offspring termed khor'-tumak by furriers and khonorik by fanciers. Such hybridisation is very rare in the wild, and typically only occurs where European minks are declining. A polecat-mink hybrid has a poorly defined facial mask, yellow fur on the ears, grey-yellow underfur and long, dark brown guard hairs. It is fairly large, with a male attaining the peak sizes known for European polecats (weighing 1,120-1,746 g and measuring 41–47 cm in length), and a female is much larger than female European minks (weighing 742 g and measuring 37 cm in length). The majority of polecat-mink hybrids have skulls bearing greater similarities to those of polecats than to minks. Hybrids can swim well like minks and burrow for food like polecats. They are very difficult to tame and breed, as males are sterile, though females are fertile. The first captive polecat-mink hybrid was created in 1978 by Soviet zoologist Dr. Dmitry Ternovsky of Novosibirsk. Originally bred for their fur (which was more valuable than that of either parent species), the breeding of these hybrids declined as European mink populations decreased. Studies on the behavioural ecology of free-ranging polecat-mink hybrids in the upper reaches of the Lovat River indicate hybrids will stray from aquatic habitats more readily than pure minks, and will tolerate both parent species entering their territories, though the hybrid's larger size (especially the male's) may deter intrusion. During the summer period, the diets of wild polecat-mink hybrids are more similar to those of minks than to the polecats, as they feed predominantly on frogs. During the winter, their diets overlap more with those of polecats, and will eat a larger proportion of rodents than in the summer, though they still rely heavily on frogs and rarely scavenge ungulate carcasses as polecats do.

The European polecat can also hybridise with the Asian steppe polecat or the North American black-footed ferret to produce fertile offspring. European-steppe polecat hybrids are very rare, despite their sympatry in several areas. Nevertheless, hybrids have been recorded in southern Ukraine, the Kursk and Voronezh Oblasts, the Trans-Carpathians and several other localities.