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Facts about the European Polecat

Scientific name: Mustela putorius

At a glance

A member of the large mustelid family (which includes the Pine Marten, Weasels and Stoats,  the Badger, and Otter) the European Polecat is one of the least-known UK mammals.

A solitary animal, the polecat occupies a variety of habitats, from farmland to woodlands to coastal sand dunes, and it typically dens in rabbit burrows, log piles, hay stacks and farm buildings. A carnivore it preys on rabbits, small rodents, amphibians and small birds.

Polecats emit a pungent odour when threatened. Their scientific name Mustela putorius translates as ‘foul-smelling musk bearer’ and refers to the smell released from their anal glands as a defence mechanism.

Historically the polecat was widespread and common in Britain, but like so many native predatory mammals the population underwent severe decline and range contraction during the 19th century as shooting estates developed and employed gamekeepers to kill anything taking rabbits and pheasants. By 1915, the polecat had become extinct across much of Britain and confined to a stronghold in mid Wales, with small populations in eastern England) Herefordshire, Shropshire, Yorkshire and Cumbria) and parts of northern Scotland. The population began to recover in Wales in the 1930s, which has been attributed to a reduction in gamekeeping during and following the First World War.

During the 20th century, polecats expanded their range from Wales into the Welsh borders and parts of the English Midlands. A survey carried out during 2004-2006 confirmed a continuation of the polecat’s range expansion, with populations now in Derbyshire, and across the south of England.

Despite legal protection, the polecat still faces threats though. Many are run over on roads, especially during the mating season (February-March) and when juveniles are dispersing in early autumn. They are also vulnerable to secondary rodenticide poisoning, becoming exposed through eating rats and other small mammals which have ingested poison. A 2018 study found that 79% of polecats had been exposed to rodenticides; a 1.7-fold increase since the 1990s. Polecats may also die or become injured in traps set for other species, such as grey squirrels, stoats and weasels.

Another increasing problem appears to be that polecats interbreed with closely-related European or Feral Ferrets (Mustela fero). Ferrets are descended from polecats and (ironically given past persecution) have been widely kept in captivity and used to hunt rabbits. Social animals, they have regularly escaped and established colonies. As polecats begin to expand from limited ranges into new territories they are coming across these colonies and interbreeding, producing fertile young.

Much like Wild Cats in Scotland that have been found to have bred extensively with domesticated cats, studies are revealing that while polecats in remote areas of Wales are genetically pure, polecats across England are increasingly mixed.

A 2021 study by the Earlham Institute asked whether this genetic introgression was actually helping polecats by introducing what is called ‘hybrid vigour’ though. Given that polecats here seem to be doing better than wild polecats in Europe, they wondered whether hybrids between polecats and ferrets are actually better adapted to the ‘new’ environment of developed Britain than their native counterparts.

Becky Shaw, a genomics expert and co-author of the report, concluded with a very interesting question: “Maybe hybridisation can prove the saviour of these polecat populations – and lead to new biodiversity that we can protect. It could have implications for other species, too, such as the European Mink, which is also suffering.”