About Mustela erminea Linnaeus, 1758
The stoat (Mustela erminea), also called the Eurasian ermine or ermine, is a mustelid species native to Eurasia and northern North America. It holds a Least Concern listing on the IUCN Red List due to its broad circumpolar distribution. The term "ermine" refers particularly to the stoat when it grows its solid pure white winter coat, and to the fur harvested from this coat. In the 15th century, ermine fur was used by Catholic monarchs, who sometimes incorporated it into mozzetta capes. It has long decorated the ceremonial robes of members of the United Kingdom House of Lords, and was also used on capes in depictions such as that of the Infant Jesus of Prague. The stoat was introduced to New Zealand in the late 19th century to control rabbit populations, but it has caused severe harm to native bird populations, leading to its nomination as one of the world's top 100 "worst invaders".
The stoat has a circumboreal range across North America, Europe, and Asia. In Europe, it occurs as far south as 41°N in Portugal, and inhabits most islands with the exceptions of Iceland, Svalbard, Mediterranean islands, and some small North Atlantic islands. In Japan, it lives from the central mountains (the northern and central Japanese Alps) to the northern part of Honshu (mainly above 1,200 m) and Hokkaido. Its vertical range spans from sea level up to 3,000 m (9,800 ft). In North America, it is found throughout Alaska and western Yukon, across most of Arctic Canada east to Greenland. Across the rest of North America, and in parts of Nunavut including Baffin Island and some islands in southeast Alaska, it is replaced by M. richardsonii. Stoats have been present in Orkney, north of Scotland, since 2010, where they prey on Orkney voles and native bird populations. In 2018, a stoat eradication effort called the Orkney Native Wildlife Project was implemented across the archipelago. By 2024, the project had spent £7.9 million trapping over 6,300 stoats.
In the Northern Hemisphere, stoat mating takes place between April and July. In spring, male stoats' testes enlarge, a process linked to increased plasma testosterone concentration. Spermatogenesis occurs in December, and males are fertile from May to August, after which the testes shrink back. Female stoats typically enter estrus (heat) for only a short period, triggered by changes in day length. Copulation can last up to one hour. Stoats are not monogamous, and litters often have mixed paternity. Stoats experience embryonic diapause: the fertilized embryo does not immediately implant in the uterus, and remains dormant for nine to ten months. This makes the gestation period variable, but it typically lasts around 300 days. After mating in summer, offspring are not born until the following spring, meaning adult female stoats spend almost their entire lives either pregnant or in heat. Females can reabsorb embryos, and may reabsorb an entire litter during a severe winter. Males do not participate in raising young. Newborn stoats are born blind, deaf, toothless, and covered in fine white or pinkish down. Milk teeth erupt after three weeks, and young stoats begin eating solid food after four weeks. Their eyes open after five to six weeks, and the characteristic black tail-tip develops one week later. Lactation ends after 12 weeks. Before kits reach five to seven weeks old, they cannot regulate their body temperature well, so they huddle together for warmth when their mother is away. Males reach sexual maturity at 10 to 11 months old, while females become sexually mature at just 2 to 3 weeks old, when they are still blind, deaf, and hairless, and are usually mated by adult males before they are weaned.
Stoat skins are highly valued in the fur trade, especially the winter coat fur. This winter coat fur is called ermine, and it is the ancient symbol of the Duchy of Brittany, forming the duchy's earliest flag. A decorative pattern called ermine, inspired by the stoat's winter coat, is also painted onto other furs such as rabbit fur. In Europe, these furs are a symbol of royalty and high social status. The ceremonial robes of United Kingdom peers and the academic hoods of Oxford and Cambridge universities are traditionally trimmed with ermine. In modern practice, rabbit fur or fake fur is often used instead, due to the high cost of ermine and animal rights concerns. Catholic Church prelates still wear ecclesiastical garments trimmed with ermine, as a marker of status equal to nobility. Leonardo da Vinci's portrait Lady with an Ermine depicts Cecilia Gallerani holding an ermine. Henry Peacham's Emblem 75 shows an ermine hunted by a hunter and two hounds, and is titled Cui candor morte redemptus, or "Purity Bought with His Own Death"; Peacham uses the image to encourage people to follow the ermine's example and keep their minds and consciences as pure as the legendary ermine keeps its fur. In heraldry, ermine is a type of tincture (a fur) made up of a white background with a pattern of black shapes that represent the stoat's winter coat. The linings of medieval coronation cloaks and other garments, which were usually reserved for high-ranking peers and royalty, were made by sewing many ermine furs together to create a luxurious white fur with patterns of hanging black-tipped tails. Largely because ermine fur is associated with the linings of coronation cloaks, crowns, and peerage caps, the heraldic tincture of ermine was usually reserved for similar uses in heraldry, such as the linings of crowns, chapeaux, and royal canopies. Both M. erminea and M. richardsonii ermine were valued by the Tlingit and other Indigenous peoples of the Pacific Northwest Coast. Ermine pelts could be attached to traditional regalia and cedar bark hats as status symbols, or made into shirts. The stoat was a core commodity in Russia's fur trade until the 20th century. At times, no less than half of the global stoat catch came from within the borders of the former Soviet Union, which produced the highest grade stoat pelts. Stoat harvesting never became a specialized trade in any part of Russia; most stoats were captured in box-traps, jaw-traps, or with dogs. In Russia, dogs typically captured stoats incidentally near villages, and were less often used for planned stoat hunts. Guns were rarely used, as they could damage the pelts.
