Falkland Islands wolf

The Falkland Islands wolf ("Dusicyon australis"), also known as the warrah, Falkland Islands dog, Falkland Islands fox, or Antarctic wolf, is a species of wolf that used to live on the Falkland Islands. They were blamed for killing sheep, but it is not known if they did or not. The last fox died in 1876. This species probably fed on penguins, seals and vegetation.
It is unclear how they got to the Falkland Islands. The most common theory was that the warrah descended from domestic dogs brought to the Falkland Islands by the Yaghan of Tierra del Fuego. This explained the lack of their fear of humans. 
However, this theory was seen as implausible because the Falkland Islands are far from mainland South America and the sea between the mainland and the islands is very windy, making it impossible to cross in simple canoes. Now, the accepted theory is that the warrah crossed into the Falkland Islands on a former ice bridge connecting the mainland and the islands.