Stoat (Mustela erminea)

French: Hermine
Spanish: Armiño
GenusMustela (1)
SizeFemale weight: 140 - 280 g (2)
Male weight: 200 - 445 g (2)
Male head/body length: 275 - 312 mm (2)
Female head/body length: 242 - 292 mm (2)
Tail length: 95 - 140 mm (2)

The stoat is classified as Least Concern (LC) on the IUCN Red List (1). Listed under Appendix III of the Bern Convention, and classified as a species of conservation concern under the UK Biodiversity Action Plan (3).

Stoats (Mustela erminea) are elusive predators, with long, slender bodies and short legs (2). The pelage is reddish to ginger in colour with white or cream underparts (2). Some individuals turn either partially or fully white in winter (2). The tail has a black tip, a feature that allows stoats to be distinguished from weasels (2). The head, which is supported by a fairly long neck, is triangular in shape, and features bright black eyes, long whiskers and round ears (4). Male stoats are much larger than females (4). At birth the kits are covered with fine white hair, and a dark 'mane' of fur forms around the neck after the third week (4).

Widespread and common throughout mainland Britain and Ireland (5), and occurs on a number of the larger islands around the UK (5). The stoat is found throughout north temperate and cold parts of Eurasia and North America (4).

The stoat inhabits a range of habitats including open moor, woodland, farmland and marsh (5).

The stoat is a carnivore, and a very skillful predator (4), typically feeding on birds and small mammals, particularly rabbits and small rodents, even taking prey as large as rats and grey squirrels (6). They hunt in a zigzag pattern, making use of features such as walls and hedgerows to provide cover, probing crevices and holes, and often standing alert on the hind legs to look around (4). Their exceptionally keen senses help them to locate prey; they try to get as close as possible to their target, before rushing in and dispatching it with a swift bite to the back of the neck (4). Males (dogs, bucks, jacks or hobs) (7) and females (bitches, does, or jills) (7) live in separate territories, which they defend against individuals of the same sex (2). In spring, males set off to search for females (2). Mating occurs in early summer, but births do not occur until the spring of the following year, as development of the fertilised egg is delayed (2) for eight to nine months (4). Between 6 and 12 blind, helpless kits are born per litter (2); after about eight weeks the young stoats begin to hunt alongside their mother (4). Females are able to mate before they are fully weaned at just 60 to 70 days of age, whereas males are unable to breed until they reach at least 2 years of age (4). Females typically stay within or close to the area of birth, and males disperse and establish large territories that overlap several female ranges (4). Predators of stoats include owls, larger carnivores and hawks (2). The average life expectancy of a stoat is just 1.5 years (5).

Stoats are controlled by gamekeepers because they prey on gamebirds (5). Historically they were trapped extensively for their winter fur (ermine). At present, competition with foxes, declines of farmland bird populations, habitat loss (5) and the effects of rodenticides (6) may all be affecting stoats (5). Although the current status of stoats in the UK is unclear, it is apparent that the population has not shown an increase following the post-myxamatosis recovery of rabbit populations (7). This fact is cause for concern regarding the conservation status of this species (7).

Research is currently being carried out to determine whether the populations of weasels and stoats, our smallest carnivores are in decline (7).

For more information on the stoat, visit:

Information authenticated by Dr Pat Morris, with the support of the British Ecological Society

  1. IUCN Red List (February, 2011)
  2. The Mammal Society. Stoat Fact Sheet. Viewed 8/7/02
  3. The Environment Agency. (1998) Species and Habitats Handbook: Look-up chart of species and their legal status. The Environment Agency, Bristol.
  4. Animal diversity web (July, 2002)$narrative.html
  6. McDonald, R.A., Harris, S., Turnbull, G., Brown, P. and Fletcher, M. (1998) Anticoagulant rodenticides in stoats (Mustela erminea) and weasels (Mustela nivalis) in England. Environmental Pollution103: 17-23.
  7. Robbie McDonald's Weasel Web, viewed 8/7/02