The Malvinas (Falkland) Islands fox-wolf, was unique, it lived cut-off from the world on a remote group of islands.
Charles Darwin surprised by its isolation, wrote that “as far as I am aware, there is no other instance in any part of the world, of so small a mass of broken land, distant from a continent, possessing so large a quadruped peculiar to itself”. 
It also holds the sad distinction of being the only species of canid to have become extinct in modern times (Canidae are a family that includes wolves, jackals, foxes, the domestic dog and the coyote).
Known as warrah or guará (Dusicyon australis) the fox-wolf of the Malvinas (Falkland Islands) belonged to the same genus as the domestic dog, the wolf and the coyote.
A veritable Patagonian wolf, it probably evolved from a now extinct South American wolf taxa, the Theriodictis and Protocyon.
Though slightly smaller than a wolf, it was much larger than the Patagonian fox, measuring 1,2 to 1,6 m (4 to 5 ft.) from the tip of its snout to the tip of its tail. Its legs were also shorter than those of a wolf, measuring 60 cm [24 in.] at the shoulder. It had a large wolfish head and thick fur to protect it from the islands’ harsh cold weather; it barked just like a dog.
It was named by the Argentine gauchos who lived on the islands until they were forcefully occupied by the British in 1833. They found it similar to northern Argentina’s Maned wolf or aguará guazú (Chrysocyon brachyurus), an unrelated canid species. The name was later corrupted into its Spanish (guará) and English names (warrah).
Their isolation was, in the end, their downfall. Being the only predator on the islands, and lacking human contact, they were fearless and curious. Their scientific name Dusicyon australis reflects this, as it means in Latin “foolish dog of the south”, alluding to its lack of fear of man, who first arrived at the islands in the early 1600s.
Captain FitzRoy who visited the islands in the 1830s remarked about their daring “all who have seen these animals alive have been struck by their eager ferocity and disregard of man's power”, as did Byron (of Wager Island fame) “four creatures of great fierceness, resembling wolves, ran up to their bellies in the water to attack the boat!”.
Darwin’s prophetic words “Within a very few years […] this fox will be classed with the dodo, as an animal which has perished from the face of the earth”, were fulfilled in less than half a century.
The warrah was hunted to extinction by the island’s shepherd settlers who considered it a predator of their herds of sheep. The last one is said to have died in 1873.
All that remains of them are a couple of jaws, eleven skulls, six stuffed furs and two embalmed foxes stored in different museums around the world.
Its origin. Unsolved mystery.
A mystifying point is how a large wolf-like predator could have evolved on the small and isolated Malvinas Islands more than 450 km (280 mi.) from the Patagonian mainland, completely surrounded by the icy and windswept waters of the South Atlantic Ocean.
Several theories have been put forward.
One proposes that its ancestors somehow drifted across the ocean on icebergs from the Patagonian ice fields.
A second theory suggests that it is the only survivor of the well-stocked pre-glacial forests that once covered the islands. At that time, about 2 million years ago, during the Pleistocene, when the islands were joined to the mainland by a land bridge, because the sea level was lower, the Warrah’s ancestors could have simply walked across. This does not explain why other animals (ñandú, guanaco or puma), or even humans did not also cross to the islands. Though, perhaps they did and died out.
A more likely option is that a group of Paleo-Indians that would later evolve into the Fuegians, who had domesticated these Patagonian foxes, took them on their canoes to the Islands. Some of these fox-dogs may have stayed behind after their masters departed or died out, and somehow adapted and survived there. However there is no evidence of the Patagonian boat people having visited these islands.
Their origin is still debated though recent DNA studies have found that its closest relative is the coyote and that it is quite distant genetically from the other South American foxes and the Aguará guazú.
Read my post on Patagonian wolves.
An unreferenced Online source mentions “news notices” during the 1982 Malvinas (Falklands) war between Argentina and Britain that spoke of a living canid that attacked the islands’ sheep.
So it may be barely possible that some of the warrah’s genes have survived through interbreeding between the last of the fox-wolves and the Border Collie type of sheep dogs brought to the islands by the Scottish shepherds.
UPDATE - Sept. 20, 2010.
Today I posted on some recent findings regarding the warrah's origin and a possible tie to the Maned Wolf and the Dusicyon avus.
 Darwin, C., (1987). The Voyage of the Beagle. Ware: Woodsworth Editions. pp. 185.
 Berta, A., (1987). Origin, diversification, and zoogeography of the South American Canidae. Fieldiana: Zoology 39, 455-471.
 FitzRoy, R. Op. Cit. vii. pp. 251.
 Skottsberg, C., (1911). The wilds of Patagonia; a narrative of the Swedish expedition to Patagonia, Tierra del Fuego and the Falkland Islands in 1907-1909. New York: Mac Millan. pp. 13.
 Serpell, J., (1995). The domestic dog: its evolution, behaviour, and interactions with people. Cambridge University.Press. pp. 13.
 Drinnon, D., (2007). Honshu Wolf Survival? (Comments). Cryptomundo.com. Online.
 Darwin, C., ed. (1838). Mammalia. The zoology of the voyage of H.M.S. Beagle... Part 2 No. 1. Plate depicting the: Falkland wolf (Dusicyon australis). Original description: Canis antarcticus.
Copyright 2009 by Austin Whittall ©