Alternative Names (Synonyms)

• Ermine
• Short-tailed weasel
• Whittrel (Scotland)
• Weasel (Ireland)
• Hermine (French)
• Hermelin (German)
• Großwiesel (German)

Alternative species names (the second part of the binomial species names): [Genus] alascensis; [Genus] algiricus; [Genus] anguinae; [Genus] angustidens; [Genus] arcticus; [Genus] audax; [Genus] bangsi; [Genus] ferghanae; [Genus] gulosa; [Genus] haidarum; [Genus] herminea; [Genus] hibernicus; [Genus] imperii; [Genus] initis; [Genus] invicta; [Genus] kadiacensis; [Genus] kanei; [Genus] labiata; [Genus] leptus; [Genus] lymani; [Genus] microtis;  [Genus] mortigena; [Genus] muricus; [Genus] nippon; [Genus] olympica; [Genus] polaris; [Genus] pusilla; [Genus] richardsonii;  [Genus] rixosa; [Genus] salva; [Genus] seclusa; [Genus] semplei;  [Genus] streatori; [Genus] vulgaris; [Genus] whiteheadi (B141).

Names for new-borns / juveniles

General Appearance

Similar Species

References

Species Author

Major References

Husbandry references:

• Wildlife and Countryside Directorate, Department of the Environment, Transport and the Regions (DETR)
• The Mammal Society
• Mammals Trust

• British Mammal Factsheets

TAXA Group (where information has been collated for an entire group on a modular basis)

Parent Group

• Mustelids

Specific Needs Group referenced in Management Techniques

• Mustelids

Husbandry Information

Notes

• Accommodation of Casualty Stoats, Weasels etc.
• Hand-rearing Stoats, Weasels etc.
• Catching and Handling of Stoats, Weasels etc.
• Feeding of Casualty Stoats, Weasels etc.
• Release of Casualty Stoats, Weasels etc.

Measurement & Weight

• male 17-24cm in North America (B52), 7.6-13in/19-33cm (B144), Britain range 27.5-31.2cm, mean 29.7cm, Ireland mean 25.2cm (B142) 
• female 6.8-11in/17-27cm (B144), Britain range 24.2-29.2cm mean 26.4cm, Ireland mean 20.8cm (B142).

Head

• Small (B148).
• Skull: Flattened (B142).
• Nose: Muzzle black, with long brown or white whiskers (B142).
• Ears: nearly flat to head. Small and rounded (B142).

• I3/3, C1/1, P3/3, M1/1
• Teeth specialised for carnivorous diet. Upper carnassials long and narrow, upper molars transversely elongated.

(B52, B142)

Legs and Tracks

• Five toes on both hind and fore feet.
• Furred between pads.
• Not webbed.

(B142).

Tail

• Moderate length.
• Brush tip black all year.

(B142, B144)

Length: approximately 6-12 cm (B142); up to 10cm B148.

• male 2-5in/5-13cm (B144), Britain range 9.5-12.7cm mean 11.0cm.
• female 2-4.4in./5-11cm (B144); Britain range 9.5-14.0cm mean 11.7cm (B142).

Coat / Pelage

• Dorsal: russet to ginger brown (B142); cinnamon-brown to yellow (B144), browny red (B148) rich chocolate brown (B147).
• Ventral: white to cream. N.B. clear straight demarcation line from dorsal brown.
• Tail tip: black.
• Whiskers: very long, brown or white.

(B52, B142, B144, B147, B148)

• White in cold climates including northern Scotland.
• Part-white also occurs in some conditions.
• Development or otherwise of white coat depends not on daylength but on minimum temperature, snowline, frost, altitude.
• Winter fur denser than summer coat
• Females more often white than males.

Mustela erminea hibernica Irish subspecies:

• Irregular dividing line on flank between dorsal and ventral colouration - ventral colour usually reduced to midline stripe only (B142).

(B52, B142, B147, B148)

• Two moults per year.
• Timing controlled by daylength.
• Spring moult: slow, starts head, progresses across back to abdomen.
• Autumn moult: faster and in opposite direction.

(B142)

• At birth: fine down, white or pinkish.
• Three weeks: prominent brown mane (temporary).
• Eight weeks: full coat.

(B142, B147)

Neonate (New-born) Characteristics

• Blind, deaf, toothless.
• Unable to maintain body temperature under 5-7 weeks.
• Huddle together when female away.
• Below 10-12°C enter reversible cold rigor (reduced cardiac and respiratory functions, reduced sensitivity).

(B142)

Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

• Reproductive: 4-5 pairs of teats (only visible in adult females). Testes in furred scrotum (not very visible in first-year individuals). Uterus simple shape (B142)(B144).
• Scent glands: Anal glands under tail. Large especially in males (B142).

Natural Diet

• Mainly small mammals, usually up to rabbit/water vole size.
• Rabbits important in Britain.
• Voles most important in continental Europe, former USSR, North America
• Also other rodents including squirrels, mice, brown rats, hares.
• Also birds, eggs, lizards, frogs, snakes, insects
• Earthworms and fruit such as blackberries may be taken when less food available.
• Minimum estimated food requirements:

• British stoats: males 57g/day (23% of body weight), females 33g/day (14% of body weight).
• German stoats (in captivity) males 19-23% of body weight, females 23-27% of body weight.
• 2-3 times increase in requirement for lactating female.
• 5-10 times increase for female while providing for dependant weaned juveniles.

(B52, B142, B144, B147, B148)

Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

Feeding Behaviour

• Hunt along familiar routes, alone or as family, in zigzag pattern.
• Concentrate effort in most profitable areas.
• Select larger prey when prey abundant.
• Locate prey mainly be sight and sound.
• Kill by rapid accurate bite at back of neck.
• Larger prey do not die instantly - probably die from shock.
• Cache surplus prey.

(B142, B147)

Parental Behaviour

• Cared for by female
• Male plays no role in rearing offspring

(B142)

Social Behaviour / Territoriality

• Variable territory size.
• Sexes live separately.
• Resident individuals defend territory against others of same sex.
• Male territory may include territory of one or more females.
• Territory size depends on available prey.
• Male territoriality breaks down in spring, with dominant males ranging widely searching for mates.
• "Hunting in packs" probably family of female and juveniles.
• Scent mark by anal drag to mark resident territory.
• Scent mark by body rubbing during agonistic interactions.
• More frequent scent marking by dominant animals.
• Male increases in dominance with: length of residence in area, age, size.
• Dominant males outrank other males (younger and intruders) and all females except females with young.
• Offensive behaviour more threats and chasing than actual fights.
• Males usually disperse, females usually remain close to natal area.

(B142) (B144, B147)

Sexual Behaviour

• Males mate both adult females and juveniles in nest.
• Dominant males may range widely looking for mates.
• Young males may stay close to single resident female.

(B142)

Predation in Wild

Activity Patterns

• Mainly terrestrial.
• Active for periods of e.g. 10-45 minutes, with periods of rest between.
• Longer active periods and greater distances covered if prey scarce.
• Travel along hedges/stone walls rather than across open spaces.
• Use regular routes.
• Remain under snow in very cold climates.
• Climb well.
• Swim well
• Run down tree trunks head first.

(B142, B143, B147, B148)

• Active at all hours although variation with season.
• Mainly nocturnal autumn and winter
• More diurnal activity spring and summer
• Diurnal activity starts earlier in spring for males than for females

(B142)(B144)

General Habitat Type

• Wide habitat range - anywhere with sufficient prey and cover.
• e.g. tundra, farmland (pastures and arable), woodland (coniferous, mixed), moorland, marsh, mountains, riverbanks, lake shores.
• Mature forests not good habitat as little ground cover, less small mammals available as prey.
• Found up to 3,000m.

(B51, B142, B147)

Nests / Burrows / Shelters

• May be 2 to10 dens in a territory.
• Dens formed from nests of prey, or in crevice, hollow log or tree roots.
• Line with dry vegetation or fur from prey.
• Also use temporary resting places.

(B142, B147)

Distribution and Movement (Migration etc.)

• Northern Holarctic.
• South to about 40°N.
• Central and northern Europe, Asia including Japan, northern North America (Alaska to northern New Mexico and Maryland), north-eastern Greenland.
• Europe: Ireland and Scandinavia to north-eastern Siberia and western Himalayas. Not in Mediterranean or some north Atlantic islands.
• Britain and Ireland: throughout mainland areas at all altitudes. Also many offshore islands greater than 60 square km.
• Not resident on some remote larger islands or on smaller islands.

(B51, B52, B142, B143, B147, B148)

New Zealand (B51, B52, B142, B143)

Intraspecific variation

• Mustela erminea erminea
• Mustela erminea hibernica (Thomas & Barrett-Hamilton, 1895) Irish subspecies irregular dividing line on flank between dorsal and ventral colouration.
• Mustela erminea minima Cavazza, 1912.

British form (larger than continental Europe) not sufficiently distinct for sub-specific status (former suggestion Putorius erminea stabalis Barrett-Hamilton 1904).

Islay and Jura form not recognised as subspecies (former suggestion Putorius erminea ricinae Miller 1907).

(B142, B143).

Conservation Status

• Not rare, not endangered (B144).

• In the UK: native, common but possibly declining. Pre-breeding population estimate of about 462,000, including 245,000 in England, 180,000 in Scotland, 37,000 in Wales. Population estimate was "based on a very limited amount of information for the species" although additional knowledge "may not necessarily have made a substantial difference to the estimate". (B221)

• Legal protection in Ireland (Eire). (B142).
• Bern Convention Appendix III (B143).