The stoat (Mustela erminea), also known as the short-tailed weasel, is a species of Mustelidae native to Eurasia and North America, distinguished from the least weasel by its larger size and longer tail with a prominent black tip. The name ermine is often but not always used for the animal in its pure white winter coat, or the fur thereof. Since the late 19th century, stoats have been introduced to New Zealand to control rabbits, but have had a devastating effect on native bird populations (see Stoats in New Zealand). It is classed by the IUCN as Least Concern, due to its wide circumpolar distribution, and because it does not face any significant threat to its survival. It is nominated among the 100 "world's worst invasive species".