Stoat

Mustela erminea
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Mustelidae
Subfamily:	Mustelinae
Genus:	Mustela
Species:	M. erminea
Binomial name
Mustela erminea Linnaeus, 1758
Range map

Pope Benedict XVI in ermine-trimmed fur coat

The stoat or ermine, Mustela erminea, is a small predatory mammal of the family Mustelidae. It is also known as a Shorttail (or Short-tailed) Weasel and less frequently as the ermelin. Sometimes "ermine" refers to the animal only when it has white fur in the winter, and in this case "stoat" only refers to it when it has brown fur.

Natural history

The stoat or ermine can be found almost everywhere throughout the northern temperate, subarctic and Arctic regions, of Europe, Asia, and North America. In an unsuccessful attempt to control the rabbit population, it was introduced into New Zealand. The animals are largely nocturnal or crepuscular but will sometimes come out during the day.

Physical description

The stoat is a member of the family Mustelidae, one of the families with the most species in the order Carnivora. The Mustelidae also includes other weasels, mink, otters, ferret, badgers, polecats, the wolverine, martens, the tayra, the fisher and in some taxonomical classifications skunks.

The stoat moves in a sinuous manner when pursuing its prey. It is extremely quick over the ground considering its small size, and is also a strong swimmer that is able to colonize offshore islands. The stoat is built long and slender, making it one of the few species able to follow burrowing animals into their own homes. It partly compensates for this shape by having short legs, small ears, a fast metabolism and, in winter, thick fur. Stoats may grow up to 30 cm long, with males much larger than the females. In most areas it coexists with the weasel (Mustela nivalis, also known as the Least Weasel), the smallest member of order Carnivora. Where the weasel is absent the stoat is smaller (~70 g).

The stoat's coat is a rich red-brown with tan or off-white belly; the tail has a conspicuous black tip. In winter, the coat is thicker, and in warmer areas it remains brown. However, in regions that experience an inch or more of snow for at least forty days of the year (such as in Armenia),^[2] the color changes to white, although the black tip to the tail remains. This white fur is known as "ermine", a term originating either from the Latin phrase "Armenius mūs" ("Armenian mouse")^[3] or from a word common to the Germanic and Baltic languages,^[4] hence the scientific name. At this stage, where the animal is known as a "stoat", it may be referred to as ermine, or as being "in ermine". The winter ermine has been used in art as a symbol of purity or virginity. The white fur was highly prized, and used in the robes of the Lord Chief Justice of England. The furs would be sewn together, the tail-tips making a pattern of black dots on a white ground. A version of this pattern is used in heraldry as ermine tincture. Both the animal and the heraldic tincture are symbols of Brittany.

In all seasons the stoat has a black tip to its tail. The black tip probably serves as a decoy to predators, which would include almost any carnivore large enough to eat a stoat (e.g. wolves, foxes, wolverines, and some birds of prey). This kind of coat is very similar to the coat of the long-tailed weasel (Mustela frenata), a related animal of about the same size which also moults into white in the northern part of its range, and it is easy to confuse these kinds of weasels. The alternative North American name for the stoat, the "Short-tailed weasel" arose because its tail length distinguishes it from the long-tailed weasel. In general it is found farther north. Both species can be distinguished from the weasel because the weasel lacks a black tip on its tail.

Geographical range

The stoat is native to the area between the 40th parallel (north) and the beginning of the Arctic Circle, which encompasses most of northern Eurasia and North America.

Stoats have been introduced to New Zealand and Australia to control a rabbit overpopulation but found the indigenous wildlife easier to catch, thus leaving the rabbit problem unsolved. They were also brought to Terschelling Island to control water voles (Arvicola terrestris). Ermines can swim up to 1.5 kilometres (0.93 mi) across seawater and have already reached several New Zealand offshore islands unaided. Programmes are currently underway to eradicate stoats from many islands in the Fiordland region of New Zealand by the Department of Conservation.

Reproduction

Young Mustela erminea

The stoat is territorial and intolerant of others in its range, especially others of the same sex. Within its range, it typically uses several dens, often taken from prey species. It usually travels alone, except when it is mating or is a mother with older offspring. It breeds once a year, producing several young kits (or kittens) per litter, and its mating system is promiscuous. Copulation occurs during the mating season with multiple partners and is often forced by the male, who does not help raise the offspring. Sometimes it occurs when the female is so young that she has not even left the den. In spite of being such a small animal, the stoat's gestation is among the longest reported for mammals (11 months) because of the adaptation of delayed implantation, or embryonic diapause, in which a fertilized egg is not implanted in the uterus until months later. The animal's "real" gestation is much shorter. This is presumably an adaptation to the highly seasonal environment in which the stoat lives.

Senses and behavior

Communication (and also location of prey) occurs largely by scent, since the stoat has a sensitive olfactory system. As a result, much of this communication is missed by human observers. However, stoats are believed to identify females in estrus by scent, and also the sex, health and age of prey. Some kinds of rodents such as voles have counter-adapted by being able to shut down reproduction (which makes females slower and easier to catch) if they smell the odor of mustelids. The stoat's visual resolution is lower than that of humans and color vision is poor although night vision is superior. Like most other non-primate mammals they have dichromatic colour vision (they can distinguish long from short wavelengths of light, but cannot make distinctions of hue within those bands). Tactile information is conferred by the vibrissae, or whiskers. When alarmed, a stoat can release a powerful musky smell from glands near its anus.

Subspecies

Stuffed stoat in Bristol City Museum, Bristol, England. The stoat is distinguished from the Least weasel by its larger size and black tip to the tail.

Ermine and the nobility

Elizabeth I of England, ‘the Virgin Queen’ painted with an ermine on her arm. In this painting the ermine has, unnaturally, black spots over its entire body.

The skins of ermine are prized by the fur trade, especially in winter coat, and used to trim coats and stoles. The fur from the winter coat is referred to as ermine. There is also a design, also called ermine, which is inspired by the winter coat of the stoat but which is painted onto other furs, such as rabbit.^[7] In Europe these furs are a symbol of royalty; the ceremonial robes of members of the UK House of Lords are traditionally trimmed with ermine^[7] although in practice rabbit fur is now often used instead. The ermine is also considered a symbol of purity in Europe. In the Renaissance era, legend had it that an ermine would die before allowing its pure white coat to be besmirched. When it was being chased by hunters, it would supposedly turn around and give itself up to the hunters rather than risk soiling itself. Cecilia Gallerani is depicted holding an ermine in her portrait, "Lady with an Ermine". Henry Peacham's Emblem 75, which depicts an ermine being pursued by a hunter and two hounds, is entitled "Cui candor morte redemptus" or "Purity bought with his own death". Peacham goes on to preach that men and women should follow the example of the ermine and keep their minds and consciences as pure as the legendary ermine keeps its fur.^[8] In some Nordic countries the ermine is invoked as a symbol of curiosity and timely action. In some areas of Japan, because of its appearance and somewhat elusive nature it is still considered a symbol of good luck.

Gallery

Painting of "Putorius erminea" (Mustela erminea)

Tracks on snow

Stoat in a tree

See also

• Stoats in New Zealand

References

Further reading

• Buckley, D.J., Sleeman, D.P. and Murphy, J. 2007. Feral ferrets Mustela putorius furo L. in Ireland. Ir. Nat. L. 28:356–360.
• King, Carolyn. The Natural History of Weasels and Stoats. London: A & C Black, 1987. ISBN 0-7470-1800-6.
• Molinia F.; La Falci S.; Myers V.; McLane D. (2007). Non-invasive monitoring of stoat reproductive hormones. Science for Conservation 276. p 24. Department of Conservation, New Zealand. [1]
• O'Connor C.; Turner J.; Scobie S.; Duckworth J.D. (2006). Stoat reproductive biology. Science for Conservation 268. p 24. [2]

External links

• ARKive
• Mustela erminea taxonomy
• Stoat control information
• Stoat 'playing'(?) in snow
• Fiordland Islands NZ stoat eradication
• BBC Wildlife finder including video footage and sound files