‘Warrah’ mystery solved at last

THE Beagle, with Charles Darwin aboard, visited the Falkland Islands in 1834.

There, the great naturalist encountered ‘the world’s loneliest animal’, the ‘warrah’. This member of the dog family, also known as the Antarctic wolf, was the sole land-mammal species on the islands which are 460km from the South American mainland. No dog could swim that far, so how did this wolf’s ancestors get there and why were they the only ones to do so? These questions, which intrigued Darwin, have remained a puzzle ever since.

Now, researchers at the University of Adelaide think they have answers; their findings appear in the current edition of the journal Nature Communications.

The warrah were first seen by an English sea captain, John Strong, who visited the islands in 1690. The ‘foolish dog’ was so friendly it swam out to greet approaching boats. Strong captured one to take home but cannon fire during the voyage panicked the unfortunate creature and it jumped overboard. Darwin was told that a warrah had entered a tent and stolen food from under a sleeping man’s head. Sailors would lure the trusting animal with meat in one hand and stab it with a knife held in the other. A shore- line scavenger, the dog ate eggs and nestling birds but, when the islands were settled in the 18th century, it was deemed a threat to sheep. Within 30 years of Darwin’s visit, it was extinct, one of the few members of the dog family to suffer the fate in modern times.

There have been several suggestions as to the warrah’s origins. According to one theory, it was deliberately introduced to the Falklands at some remote time in the past. Indeed, its presence was deemed to be evidence that the islands were visited by people long ago.

Finds of arrowheads and the remains of a canoe on the islands supported this contention, until it was shown that these had belonged to Yanghan people from Tierra del Fuego attached to a mission station established in the 19th century. In any case, why would anybody go to the trouble of introducing such an animal?

A paper published in Current Biology in 2009 claimed the warrah’s nearest living relative is the maned wolf of South America. This was based on a DNA analysis which showed that the two species shared an ancestor about seven million years ago.

The Adelaide University researchers have come up with a more detailed family tree.

They extracted DNA from specimens Darwin collected and bones discovered recently in a New Zealand museum. Comparing these with samples taken from other South American dog species, they believe that the warrah’s closest relative was Dusicyon avus, an extinct fox-like creature. The warrah’s line, the DNA analysis shows, split from that of D. avus around 16,300 years ago. The date of the separation is significant; it helps explain how the dog got to the Falklands.

The problem of land animals crossing the sea is a familiar one to us here in Ireland. How the wolf, giant deer and a host of smaller creatures, managed to reach our own island long ago has been much discussed. The last ice age was at its height 16,000 years ago and sea levels near the southern tip of the Americas, like everywhere else, were much lower than they are now. It’s estimated that, at that time, the channel between the Falklands and the mainland was only 24km wide. Ice resting on submarine terraces in shallow seas could have connected the islands to the mainland. In northern climes today, arctic foxes hunt along frozen coasts, pursuing seabirds or seeking carcases of sea mammals borne in on the tide. The warrah probably did the same in the southern hemisphere. Venturing onto the ice, in pursuit of young seals and penguins, it could have found its way to the Falklands just as wolves are thought to have reached Ireland over a similar icy land-bridge later.

* JJ Austen et al. The origins of the enigmatic Falkland Islands wolf. Nature Communications 4.