Sunday 19 May
Weasel (Mustela nivalis)
What’s the World’s Favourite Species?Find out here.
Weasel fact file
- Find out more
- Print factsheet
Britain's smallest native carnivore (2), the weasel (Mustela nivalis) has a long slender body, and a short tail. The fur is ginger to a rich chocolate-russet brown in colour, and the underparts are creamy-white (2). The narrow head is supported on a long neck, and the legs are short (1). The large eyes are black, and the ears are rounded (1). In northern parts of the range, weasels turn white in winter, but they do not do so in the UK (2).
- Belette D'Europe.
- Female weight : 55 - 69 g (2)
- Male weight: 106 - 131 g (2)
- Male head-body length: 194-217 mm (2)
- Female head-body length: 173-183 mm (2)
- Male tail length: 42-52 mm (2)
- Female tail length: 34-43 mm (2)
Weasels are active at any time of day or night, and intersperse periods of activity with a rest period (3). They feed mainly on small rodents, rabbits, birds and eggs (3), killing prey with a bite to the neck (1). Their small size enables them to enter the tunnels of mice and voles whilst hunting (2), and they often take over the nests of their prey, lining their dens with fur from prey during cold weather (2). A number of dens will be used within the home range. Males and females occupy separate territories, and defend these against members of the opposite sex (2). During spring, males move around in search of a mate (2). The male and female often fight prior to copulation, and the male grabs the female by the neck before he mates (1). A single litter of between 4 and 6 (2) naked, blind and deaf (1) kits is produced each year; the kits are weaned after 3 to 4 weeks and begin to hunt well by 8 weeks of age (2), often accompanying their mother to hunt in 'gangs' (2). By 9 to 12 weeks after birth the family group starts to split up (1).
Historically, weasels were believed to have magical powers, and were said to be able to bring their dead young back to life. It was also thought that they hypnotised their prey by dancing (4); in fact 'dancing' behaviour is thought to be a response to discomfort caused by internal parasites (2).Top
The weasel is widespread throughout mainland Britain, and on large islands around the UK, but absent from Ireland (3). It also occurs throughout much of Europe, reaching into Asia as far east as Japan, as well as in North America (3).Top
The weasel is classified as Least Concern (LC) on the IUCN Red List (7), and a species of conservation concern by the UK Biodiversity Action Plan, although not a priority species. Listed under Appendix III of the Bern Convention (3).Top
Populations of weasels are controlled because they take gamebird eggs and chicks (3). Likely threats include habitat loss and simplification, as well as predation by foxes. Agricultural changes have led in many areas to the loss or reduction of rough grasslands, which is prime habitat for the field vole, a key source of food for weasels (3). Evidence is building that rodenticides are having an effect on weasels and stoats, as they eat poisoned rodents (5).Top
Find out more
For more information on this species:
BBC Wildlife Finder:
Information authenticated by Dr Pat Morris, with the support of the British Ecological Society
- Home range
- The area occupied by an animal during routine activities, which is not actively defended.
- An area occupied and defended by an animal, a pair of animals or a colony.
Animal diversity web. (July 2002)
The Mammal Society. Weasel Fact Sheet. (July 2002)
- The Environment Agency. (1998) Species and Habitats Handbook: Look-up chart of species and their legal status. The Environment Agency, Bristol.
Macdonald, D.W. and Tattersall, F.T. (2001) Britain's mammals- the challenge for conservation. The Wildlife Conservation Research Unit, Oxford University.
UK Safari (July 2002)
- 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.
IUCN Red List (February, 2011)
More »Related species
Play the Team WILD game
Terms and Conditions of Use of Materials
Visitors to this website (End Users) are entitled to:
- view the contents of, and Material on, the website;
Additional use of flagged material
Green flagged material
Creative commons material
Any other use