Stoat facts, pictures and information. Also known as the ermine or short-tailed weasel, the stoat is a small carnivorous mammal found throughout the Northern Hemisphere.
Although it looks cute, the stoat is an accomplished predator, capable of taking prey much larger than itself.
Stoat Facts At A Glance
- Other Name(s): Ermine, short-tailed weasel
- Scientific name: Mustela erminea
- Type of Animal: Mammal
- Animal Family: Mustelidae
- Where Found: North America, Europe and Asia
- Length Male: 18.7 to 32.5 cm (7.4 to 12.8 in); Length Female: 17.0 to 27.0 cm (6.7 to 10.6 in)
- Average Weight Male: 258 g (9.1 oz.), male; Average Weight Female: 180 g (6.3 oz.)
- Conservation Status: Least Concern
Meet The Stoat: Introduction
The stoat is a small predatory mammal in the family Mustelidae. It is found all throughout much of the northern hemisphere, and has also been introduced to New Zealand.
The stoat is also known as the short-tailed weasel, especially in North America, where the related long-tailed weasel is also present.
Another common name for the stoat is the ermine. This name is most often used to refer to the animal in its white winter coat. (The name ermine can also refer to other animals in the genus Mustela).
Stoat Family & Related Animals
The stoat is a member of the family Mustelidae. This family is sometimes called the ‘weasel family’. In addition to weasels (including the stoat), Mustelidae also contains badgers, otters, martens, mink and the wolverine. It is the largest family in the order Carnivora.
- You can find out more about Carnivora, and other types of mammal, here: Types of Mammal.
The stoat’s closest living relations include the mountain weasel (Mustela altaica), the least weasel (Mustela nivalis) and the long-tailed weasel (Mustela frenata). Like the stoat, they are in the genus Mustela. (The least weasel is known as the weasel in the UK.)
Over 30 subspecies of stoat have been identified.
What Does The Stoat Look Like?
The stoat has a slender, elongated body, a long neck and triangular head. Its legs are short, and there are 5 toes on each paw. The soles of the stoat’s feet are covered in thick fur.
The stoat’s long, thin body is an adaptation for hunting small burrowing creatures. It can pursue its prey into their burrows, and also under the snow.
One disadvantage of the stoat’s body shape is that heat is easily lost through the relatively large surface area. This means that the stoat has to consume a large amount of food to get the energy it needs to stay warm.
The stoat’s ears are small and rounded and its whiskers are particularly long. The tail measures 65 to 120 mm (2.6 to 4.7 in) and has a black tip.
Male stoats are up to 25% larger than the females and can be twice as heavy.
Stoat Summer & Winter Coats
The stoat molts twice a year (in spring and autumn). During the summer its coat ranges from sandy brown to reddish brown in color. The undersides and feet are white or cream. The coat is also short and coarse during this time.
With the autumn molt, the stoat’s coat becomes white all over. The winter coat is thicker, longer and softer than the summer coat.
The tip of the stoat’s tail remains black throughout the year (even in winter).
It is thought that the black tip is a defensive adaptation. A bird of prey will aim for the black tip, rather than the stoat’s white body. The bird experiences a brief moment of confusion when it realizes the tail is part of a larger animal, giving the stoat a chance to escape.
Confusion With Similar Animals
The stoat can easily be confused with other members of the genus Mustela, including the least weasel and the long-tailed weasel.
Stoat Vs Least Weasel
The stoat shares much of its range with the closely-related least weasel.
The stoat is larger than the least weasel and has a proportionally longer tail. The stoat’s tail has a black tip, whereas that of the least weasel is a uniform brown.
Stoat (Short-Tailed Weasel) Vs Long-Tailed Weasel
In the Americas, the stoat shares much of its range with the long-tailed weasel, another similar-looking species.
The stoat is smaller than the long-tailed weasel, but because it is unlikely for the two animals to be seen side by side in the wild, the tail is often the best means of identification.
As its name suggests, the long-tailed weasel’s tail is proportionally longer than that of the stoat, and can be up to half of the animal’s body length. In contrast, the stoat’s tail is around a third of the length of its body.
The tails of both animals have a black tip, therefore tail length (rather than appearance) is the most useful distinguishing feature.
Stoat Facts: Distribution
The stoat has a wide distribution range (the area in which it is found). The species occurs in both Arctic and temperate (between polar and tropical) regions of North America, Europe and Asia. The southern limit of the animal’s range lies around 35°N.
The species originated in Eurasia. It migrated to North America around 500,000 years ago, making its way over the Bering Land Bridge – a piece of land that once joined North America to Eurasia.
Stoats In New Zealand
The stoat was introduced to New Zealand in the 19th century as a means of controlling rabbits (also an introduced species). The species is now considered a pest, and its presence in the country is a significant threat to many native birds.
Stoat / Ermine Habitat
The stoat is found in a wide range of habitats. These include: coniferous and mixed woodlands, scrub, alpine meadows, marshes, hedgerows, forest-edges, riverbanks, tundra, taiga (northern forests), forest-steppe and semi-desert. The animal avoids very dense forests and deserts.
The stoat can be found at altitudes of up to 4,050 m (13,300 ft.).
Although the stoat may be active at any time of the day it typically hunts at night.
The stoat is territorial, with both sexes using urine, droppings and scent to mark their home ranges. The male’s territory is larger than the female’s, and typically contains the territories of several females.
A stoat’s home range often contains several dens. These consist of rodent burrows, hollow logs, cracks in stone walls, heaps of brushwood and rock piles.
The dens are lined with dry vegetation, as well as with fur and feathers from prey animals. They may have side chambers that are used as latrines and food caches.
Although the stoat is not a particularly vocal animal, it does use vocalizations such as whines, squeals, hisses and barks to communicate states such as dominance, submission and readiness to mate.
Stoats also communicate by scent. In addition to the prominent anal scent glands (which the stoat has in common with many mustelids), the stoat has scent glands on its cheeks, belly and flanks.
The stoat is a ground-dwelling animal. It is also adept at climbing and swimming, and can run on snow. Its long, thin body shape allows it to move easily inside underground burrows.
The stoat frequently stands upright on its hind legs with its head held up in order to survey its surroundings.
Stoat Facts: Breeding
Stoats mate in the spring or early summer (April to July). Both male and female stoats mate freely with multiple partners, and kits (young) in the same litter can have different fathers.
The female has one litter of 3 to 18 kits per year. The development of the fertilized eggs begins after a delay of 8 to 9 months, and is triggered by an increase in daylight.
The newborn stoats are blind, deaf and toothless. Their bodies are covered in fine, light-colored down. For an unknown reason, a prominent mane of dark fur grows around the neck of the young at around 3 weeks.
The kits start eating solid food at around 4 weeks of age, and begin to accompany their mother on hunting trips from 8 weeks. They are fully weaned after 12 weeks. Only female stoats take part in looking after the young.
What Do Stoats Eat?
The stoat is an effective predator of small mammals, specializing in rodents and lagomorphs (hares, rabbits and pikas). Occasionally (or when its preferred prey is not available) the stoat will also feed on birds, eggs, earthworms, insects, amphibians, lizards and fish.
The stoat usually hunts at night. It uses its keen senses of smell, sight and hearing to locate its prey, typically getting as close as possible before striking.
The stoat often hunts for rodents inside their burrows. It may also climb trees in search of bird eggs, and hunt under the snow in the winter.
The stoat typically consumes around 50 g (1.8 oz.) of food – or roughly a quarter of its own weight – per day. Surplus food is frequently stored in caches to be eaten later.
Stoat / Ermine Predators
The stoat may fall prey to some larger predators, such as red foxes, badgers, owls and hawks.
Is The Stoat Endangered?
The stoat is rated ‘Least Concern’ by the IUCN.
The species is usually common, has a huge range and no major threats have been identified.
In some areas, stoat populations may be threatened by a variety of factors, including habitat loss, unrestricted trapping, competition with other predators and a decline in prey species.