The American mink escaped the fur farm and remade European riversides
A mink with no white patch on its upper lip is certainly American, because every European mink has one. That small detail matters in Europe, where American mink bred for their fur have escaped or been released from farms, gone wild, and are thought to have helped push their European cousins into decline.
Mink are dark, semiaquatic hunters in the weasel family, related to otters, badgers and martens. Two species survive: the larger, more adaptable American mink and the European mink, which is actually closer kin to polecats. A third, the much bigger sea mink of New England, was hunted out for its fur in the late 19th century. A wild male American mink weighs about 1 kg and measures roughly 60 cm without its tail, while farm-bred males can reach 3.2 kg. The natural coat is a glossy deep brown of dense underfur beneath stiff guard hairs, but farm breeding produced colours from white to near black, a range now seen among feral mink in Britain.
They rarely stray far from rivers, lakes and marshes, though they will leave the water for a few hundred metres to chase rabbits, a favourite prey, and in Scotland and Iceland some live on the seashore. Fish, birds, eggs and small mammals round out the diet. Each animal holds a long, narrow territory along a bank, sometimes several miles long, centred on one or two core areas near a rich food source; excursions to the edges seem to be patrols, marked with scented droppings. Males tolerate females but not other males.
Breeding has a curious twist called delayed implantation. True gestation lasts 39 days, but the embryo can pause, so up to 76 days may pass before six to 10 kits arrive, once a year. Mink can live around ten years yet seldom exceed three in the wild.
Farming has brought other problems. Caged mink often develop repetitive abnormal behaviours, and in October 2022 mink on a Spanish farm provided the first observed mammal-to-mammal spread of the H5N1 bird flu. In Ireland, where campaigners released three thousand mink in the 1960s, an estimated 33,500 now live wild.
Source: Mink
