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American mink arrived in the UK in 1929. They were first reported to be breeding wild in 1956. Today, it's virtually impossible to estimate the number of mink living in our waterways.
Scientific name: Neogale vision
Family: Mustelidae
Diet: Mink are opportunistic carnivores who will eat a variety of fish, birds, invertebrates and small mammals, including the endangered water vole.
Size: 30-43cm (Mink males are larger and heavier than females, and their size can vary considerably depending on their location).
Weight: 0.5-1.5kg
Lifespan: 10-12 years
American mink
American mink (also referred to as just 'mink') were introduced to the UK from North America for fur farming in the 1950s. After escaping these farms, and with no natural predators to hunt them, they rapidly spread across the country.
A semi-aquatic mammal, they often frequent canals and rivers - typically along waterway banks or in grassland habitats.
Mink are solitary animals that will fiercely defend their waterside territories. Males will sometimes allow females to make their homes inside their vast dens, but no male mink will tolerate another male nearby. The expanse of their living quarters means they often overlap, which can result in frequent fighting amongst males - particularly in the mating season.
Mink are efficient and opportunistic predators. They do not hibernate, and their relentless hunting is having a devastating impact on native species like the water vole. As well as hunting adult water voles, female mink use their expert swimming skills and slender size to enter burrows and take their young.
Unless some areas are kept free or relatively free of mink, it's thought that the water vole will become extinct in much of Britain within a few years.
The urgency of the situation is highlighted by the water vole's inclusion as a priority species in the UK Biodiversity Action Plan and the promotion of humane mink control as an essential tool in water vole conservation, within the National Species Action Plan.
Schedule 9 of the Wildlife and Countryside Act 1981 also means it is now an offence to release or allow the escape of mink into the wild across England, Wales and Scotland.
American mink have a dense coat of deep brown-black fur, and have a white chin and throat marking. They are slightly larger than a weasel, but not quite as big as a cat.
At first glance, it's easy to mistake an American mink for a native otter. However, otters are larger in size, and have a broader snout. Their colouring is a lighter brown with an even paler underbelly, and they are unlikely to be seen during the day due to their shy nature.
Mink only breed once a year. They tend to use existing spaces to nest, such as hollows in trees or exposed root formations. But, if needs must, they are quite capable of burrowing a new space.
Mating season falls between February and April, with births usually occurring before the end of May. However, female minks have a unique ability to delay birth for up to six weeks in favour of better weather, or to wait for an increased food supply.
Baby mink, known as kits, are born blind, deaf and furless, weighing around five grams. A litter tends to be between three and seven big, with kits becoming fully independent by fourteen weeks of age.
When threatened, mink may hiss, snarl and screech loudly. When content, they make a purring sound.
Last Edited: 09 April 2025
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