Short-tailed weasel

The stoat (Mustela erminea), also known as the short-tailed weasel or simply the weasel in Ireland where the least weasel does not live, is a mammal of the genus Mustela of the family Mustelidae native to Eurasia and North America, distinguished from the least weasel by its larger size and longer tail with a prominent black tip. Originally from Eurasia, it crossed into North America some 500,000 years ago, where it naturalized and joined the notably larger, closely related native long-tailed weasel. The name ermine is used for any species in the genus Mustela, especially the stoat, in its pure white winter coat, or the fur thereof. In the late 19th century, stoats were introduced into New Zealand to control rabbits, where they have had a devastating effect on native bird populations. The stoat is classed by the International Union for Conservation of Nature (IUCN) as least concern, due to its wide circumpolar distribution, and because it does not face any significant threat to its survival. It was nominated as one of the world's top 100 'worst invaders'. Ermine luxury fur was used in the 15th century by Catholic monarchs, who sometimes used it as the mozzetta cape. It was also used in capes on images such as the Infant Jesus of Prague. The root word for 'stoat' is likely either the Dutch word stout ('naughty') or the Gothic word ??????? (stautan, 'to push'). According to John Guillim, in his Display of Heraldrie, the word 'ermine' is likely derived from Armenia, the nation where it was thought the species originated, though other authors have linked it to the Norman French from the Teutonic harmin (Anglo-Saxon hearma). This seems to come from the Lithuanian word šarmu. In Ireland (where the least weasel does not occur), the stoat is referred to as a weasel, while in North America it is called a short-tailed weasel. A male stoat is called a dog, hob or jack, while a female is called a jill. The collective noun for stoats is either gang or pack. The stoat's direct ancestor was Mustela palerminea, a common carnivore in central and eastern Europe during the Middle Pleistocene, that spread to North America during the late Blancan or early Irvingtonian. The stoat is the product of a process begun 5–7 million years ago, when northern forests were replaced by open grassland, thus prompting an explosive evolution of small, burrowing rodents. The stoat's ancestors were larger than the current form, and underwent a reduction in size as they exploited the new food source. The stoat first arose in Eurasia, shortly after the long-tailed weasel arose as its mirror image in North America 2 million years ago. The stoat thrived during the Ice Age, as its small size and long body allowed it to easily operate beneath snow, as well as hunt in burrows. The stoat and the long-tailed weasel remained separated until 500,000 years ago, when falling sea levels exposed the Bering land bridge. Combined phylogenetic analyses indicate the stoat's closest living relative is the mountain weasel (Mustela altaica), though it is also closely related to the least weasel (Mustela nivalis) and long-tailed weasel (Mustela frenata). Its next closest relatives are the New World Colombian weasel (Mustela felipei) and the Amazon weasel (Mustela africana). As of 2005, 37 subspecies are recognized.