Stoat (Mustela erminea): Facts, Ermine Coat and Diet

What does a stoat look like?

A stoat has the classic weasel shape: a long, almost tube-like body, short legs, a long neck and a small, flat head with short rounded ears and bright black eyes. The whiskers are long, and the head sits well in front of the shoulders, which helps the animal push into burrows and gaps between stones.

In summer the coat is sandy or chestnut brown on the back and head and creamy white on the throat and belly. The line between the two colors is usually straight. The tail is about a third of the body length or a little more, and its last few centimeters are always black, in summer and in winter. That black tip is the easiest way to tell a stoat from a least weasel, whose tail is shorter and plain brown.

The ermine: why some stoats turn white

Stoats molt twice a year. The autumn molt is triggered mainly by the shortening days, and in the north of the range the new coat grows in pure white except for the black tail tip. A stoat in this coat is called an ermine. In milder areas the winter coat stays brown, only thicker, and in places in between, such as much of Britain, stoats may turn partly white, with patchy or “piebald” coats.

White fur hides the animal against snow from predators such as foxes and owls, and from the prey it stalks. The full story, including why the tail tip never turns white, is covered in why do stoats turn white in winter.

How big is a stoat?

Stoats are small, but they are clearly bigger than least weasels. Body size varies a lot across the range, and, unusually for a carnivore, animals tend to be smaller toward the far north rather than larger.

Males are roughly a quarter longer than females and can weigh about one and a half to two times as much. That size difference matters in the wild: smaller females can follow voles and mice deep into their tunnels, while larger males more often take rabbits and water voles.

Habitat and range

The stoat has a circumpolar range in the cool and cold zones of the Northern Hemisphere. In Europe it lives from Portugal and northern Spain to Scandinavia and Russia, and it is found on Britain and Ireland, though not on Iceland or the Mediterranean islands. In Asia it ranges across Siberia to China, Mongolia and Japan, and it occurs from sea level up to about 3,000 m (9,800 ft).

Stoats use almost any habitat with enough cover and small prey: woodland edges, hedgerows and farmland, moorland, rough grassland, marshes, riverbanks, mountain slopes and Arctic tundra. They avoid dense forest interiors and open land with no cover. They do not dig their own dens but take over the burrows or nests of rodents they have killed, lining the nest chamber with fur from their prey.

People also introduced stoats to New Zealand in the 1880s, where they have become a serious invasive predator. More recently stoats reached the Orkney Islands off Scotland, where they had never lived before, and a large eradication project has been running there since 2018.

A recent split in North America

Until recently the stoat was treated as one species stretching right across North America. In 2021 a genetic study split it into three species: the stoat (Mustela erminea) in Eurasia and the far north of North America, the American ermine (Mustela richardsonii) across most of Canada and the United States, and the Haida ermine (Mustela haidarum) on a few islands off the Pacific Northwest coast. Many field guides in North America still call all of them the ermine or short-tailed weasel.

What do stoats eat?

Stoats are carnivores that live mainly on small mammals. Voles and mice form the core of the diet in most places, but stoats also take water voles, rats, young hares, birds, eggs and, less often, fish, frogs, lizards and insects. In Britain the European rabbit is a major prey, especially for males, and stoats became more common there as rabbit numbers recovered from the disease myxomatosis.

A stoat can kill a rabbit several times its own weight with a fast bite to the back of the neck. It also climbs trees well to raid nests and nest boxes, and it can swim. A stoat needs to eat about a quarter of its body weight each day, roughly 50 g (1.8 oz), and when food is plentiful it may kill more than it needs and cache the extra.

Stoats are also famous for the “dance”, a burst of leaps, twists and somersaults sometimes seen near rabbits. For more on prey and the theories behind the dance, see what do stoats eat.

Behavior and communication

Stoats are mostly solitary. A male’s territory usually overlaps the smaller territories of one or more females, and both sexes mark their ground with droppings, urine and scent rubbed from glands on the body. When alarmed, a stoat can release a strong musky smell from its anal glands.

They are active by day and by night, hunting in short, busy bursts. A stoat searches every hole, crevice and tuft it passes and often stands up on its hind legs to look around. In winter it hunts under the snow along rodent runways. Stoats can travel several kilometers in a night, and the territories of dominant males are far larger than those of younger males.

Stoats are usually quiet, but they trill, hiss, bark and screech during fights or when threatened, and the young make chirping calls in the nest.

Reproduction and life cycle

Stoats mate in late spring and summer, but the young are not born until the following spring. The reason is delayed implantation: the fertilized egg develops a little and then pauses, floating in the womb for about nine to ten months before it attaches and growth resumes. Lengthening days in late winter restart development, and the kits are born in April or May, about four weeks after implantation.

A litter usually has about 4–9 kits, though litters of up to 18 have been recorded. The kits are born blind, deaf and toothless, with a thin coat of fine white hair, and the black tail tip appears at around six or seven weeks old. The mother raises them alone and teaches them to hunt; the family breaks up in summer.

One of the most remarkable facts about stoats is that young females become fertile when only a few weeks old, often before they leave the nest. Adult males visit the nest and mate with them, so almost every female stoat is pregnant for most of her life.

Lifespan, predators and threats

Most wild stoats live only one to two years, and a few reach about seven. In captivity they have lived to about 12 years. Many die young from starvation in hard winters, from predators or on roads.

Stoats are hunted by red foxes, martens and other larger carnivores and by birds of prey, from owls and buzzards to golden eagles; even gray herons sometimes take them. In some parts of Europe they are still trapped for fur or controlled on game estates. A parasitic worm that damages the bones of the nose and sinuses is also common in some populations.

Conservation status

The IUCN Red List classifies the stoat as Least Concern, with a stable population. It has an enormous range, uses many habitats and breeds quickly, so numbers recover well after crashes. Local numbers rise and fall with prey: years with many voles or rabbits produce many stoats.

Myths and facts

Myth: Stoats hypnotize rabbits by dancing. The stoat’s dance is real, and rabbits sometimes watch it closely, but there is no evidence that it hypnotizes them. Some researchers think it may be play or excitement, and others link it to irritation caused by a parasitic worm in the sinuses.

Myth: A white ermine would rather die than get its coat dirty. This was a popular European legend and a symbol of purity, which is partly why ermine fur was used on royal robes. Real stoats roll in mud and dust like any other small mammal.

Fact: Stoats and ermines are the same animal. “Ermine” is simply the name used for the stoat in its white winter coat and for its fur.

Stoats and people

For centuries ermine fur was a symbol of royalty and high rank in Europe. White pelts with their black tail tips were sewn onto coronation cloaks and the robes of peers in the UK House of Lords, and the pattern became the heraldic fur called “ermine”. Leonardo da Vinci painted Lady with an Ermine in about 1490, and the stoat inspired the mascots of the 2026 Winter Olympics in Milan and Cortina.

On farms and in gardens stoats help control rats, mice and rabbits, but they also take poultry and game-bird chicks, which has long made them unpopular with gamekeepers. In New Zealand they are a major threat to native wildlife, and they are a key target of the country’s plan to remove introduced predators, explained in why stoats are a problem in New Zealand. To tell a stoat from its smaller relative, see stoat vs weasel.