Stoat:
The stoat (Mustela erminea), also known as the short-tailed weasel or simply the weasel in Ireland where the least weasel does not occur, 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. [Wikipedia]
Noted in “Why ancient deer returned to the sea and became whales,” Colin Barras, NewScientist (24 March 2018, paywall):
Some of the most spectacular species now living in the sea have land-living ancestors. Whales are descended from animals similar to deer, while walruses evolved from animals a bit like stoats.
