UK polecat numbers may be rising due to interbreeding with ferrets

Jake Buehler is a writer.

In Britain, many wild polecats are ferrets. The weasel-like mammals have spread from a small population in Wales to a large one.

The ancestors of ferrets are believed to be the European polecats. Polecats were once widespread in Britain, but by 1900 they were only found in a small part of the Welsh forest.

The Wildlife & Countryside Act of 1981 has contributed to the recovery of the polecat. The polecat population has expanded eastward through England. According to Graham Etherington at the Earlham Institute, researchers hadn't determined the extent of interbreeding.

Etherington and his colleagues took samples from 49 different Mustela individuals. The mammal's genomes were analysed by the team.

The British polecats had evidence of interbreeding with ferrets, which is similar to their pattern of geographical expansion.

The more far away you are from Wales the more ferret-like they get.

ferret origins were found in many individuals that appeared to be pure polecat.

The English population of hybrid polecats had genes from ferrets. The polecat may have an advantage because of the versions of the genes that have been selected.

There are two human versions of genes that are thought to have roles in cognitive and vision in humans. Etherington wonders if such ferret genes augmented hunting ability, became a more prominent feature in ferrets due to human breeding, and now are finding a second life in polecats.

There could be positives for rare species that hybridise with family members.

According to Hailer, interbreeding may help species survive by giving them access to genetic variation that they don't have themselves.

There are notable genetic differences between Welsh polecats and their English and mainland cousins, as well as whether the Welsh population could be a separate species.

The journal is called Journal of Heredity.