Argentinean Warrah

How the Argentinean warrah became the Falkland Islands wolf

During the last ice age, around 16,000 years ago, a few Argentinean warrahs used shallow, frozen parts of the sea to travel from South America to the Falkland Islands, 500 kilometers away. Over time, the Argentinean warrah on the Falkland Islands developed differently from its continental relatives. This gave rise on the islands to a new species of the genus Dusicyon: the Falkland Islands wolf, or warrah. The remaining Argentinean warrahs stayed on the South American continent. Today, both species are extinct.

There is therefore a close relationship between the Falkland Islands wolf and the Argentinean warrah. Since the Falkland Islands wolf essentially emerged from the Argentinean warrah, the Argentinean warrah is both its ancestral form and its sister taxon.

The Argentinean warrah was widespread in southern South America. Scientists have found fossil remains in Argentina, Brazil, Chile and Uruguay, for example. It preferred open habitats such as grass or shrub steppes, like those found in the Pampas and Patagonia regions.

While the Falkland Islands wolf, as the only land mammal on the Falkland Islands, fed mainly on birds, the Argentinean warrah’s diet consisted of small mammals and carrion, which could also be large. According to studies, it was more strongly carnivorous (meat-eating) than foxes living today.

Argentinean warrah – fact sheet

scientific names	Dusicyon avus, Canis avus, Canis platensis
original range	southern South America (Chile, Uruguay, Argentina, Brazil)
time of extinction	unclear, possibly early 17th century, perhaps not until the 20th century
causes of extinction	anthropogenic impacts (such as the introduction of domestic dogs,  habitat loss, hunting), climatic changes

Extinct much later than assumed—the Argentinean warrah

For a long time, scientists assumed that the Argentinean warrah had already become extinct about 3,000 years ago. Travel diaries and traditions from more recent times, however, suggest that the species may have existed longer. This is indicated, for example, by the South American travel impressions of George Chaworth Musters, a former commander in the British Royal Navy, in At Home with the Patagonians (1873). In it, he describes an encounter with a fox in Patagonia that was said to resemble a warrah. Warrah is a variant of the word aquará, which in Guaraní, one of the native languages of the Americas, means something like fox. The Falkland Islands wolf on the Falkland Islands was also called the warrah. Musters may therefore actually have encountered the Argentinean warrah.

Certainty came in 2015 from a study in which the paleontologist Francisco J. Prevosti and his colleagues used radiocarbon dating to determine that the Argentinean warrah became extinct much later. For the Pampas region, Prevosti determined an extinction period between 1232 and 1397, and in Patagonia the Argentinean warrah existed between 1354 and 1626.

It may have existed even longer, because the South American Selk’nam people, who once lived on Tierra del Fuego, an archipelago at the southern tip of South America, knew of two fox variants around 1900. One of these foxes was said to have been unusually large. If this large fox was the Argentinean warrah, it would mean that it survived on Tierra del Fuego even into the 20th century, according to the archaeologist Luis A. Borrero in American Megafaunal Extinctions at the End of the Pleistocene (2008).

According to the Encyclopedia of Life, the Argentinean warrah is said to have reached the size of a German shepherd. This is a rather vague statement, but it is certain that the Argentinean warrah was larger than other South American foxes. Its weight was between ten and 15 kilograms.

Three hypotheses on the extinction of the Argentinean warrah

In contrast to the Falkland Islands wolf and its pronounced island tameness, the reasons for the extinction of the Argentinean warrah are rather mysterious. Why would this widespread, unspecialized predator of medium body size become extinct?—And so long after the Quaternary extinction event, the mass extinction at the transition from the Pleistocene to the Holocene.

In the past, scientists mainly discussed three hypotheses that could have led to the disappearance of the species: climate change, crossbreeding with domesticated dogs and the influence of the Indigenous population. Prevosti can rule out the first two hypotheses at once, because there is no evidence that the wetter climate harmed the foxes. Nor did hybridization between Argentinean warrahs and domestic dogs take place, since the genetic material, fox skulls and fox dentition show no conspicuous changes from the Pleistocene to the Holocene.

The fox and humans

Remains, especially teeth, of the Argentinean warrah in numerous archaeological excavation sites indicate that the predator had high symbolic value for the Indigenous inhabitants of South America and served ritual purposes in the late Holocene. The Indigenous population presumably wore the teeth of the Argentinean warrah around their necks as jewelry.

In 2015, the archaeologist Luciano Prates examined the relationship between wild canids and humans. The occasion was the discovery of a grave from the late 2nd millennium BC in the Argentine province of Rio Negro. It contained the remains of an Argentinean warrah, which had been buried in a way comparable to humans at the time. It seems likely that it was kept as a pet and regarded as part of the human social community.

A new study by the University of Oxford from 2024 confirms the assumption that the Argentinean warrah had a special bond with hunter-gatherer groups about 1,500 years ago and did not serve as food for them. The scientists identified the absence of cut marks on the animal’s bones, the burial of the fox within a human settlement and similarities in diet between the fox and the humans as important evidence of a non-predatory relationship. However, the question remains open whether the Argentinean warrah was actually domesticated and kept as a pet.

Prevosti considers it possible that the growing population in the late Holocene may have further intensified the use of the animal species for religious purposes. Perhaps even so much that it negatively affected Argentinean warrah populations? The radiocarbon dates from Prevosti’s study, however, indicate that the Argentinean warrah disappeared only in more recent times, after the settlement of South America by Europeans. It can therefore be said with reasonable certainty that the pre-European population, with its ritual practices, cannot alone have eradicated the fox.

The colonization of South America and its consequences

The settlement of the Pampas and Patagonia regions by Europeans was accompanied by major environmental changes that accelerated the extinction or population decline of various large mammals (herbivores and carnivores). The jaguar (Panthera onca), for example, became locally extinct as a result; and the population numbers of the puma (Puma concolor) and Pampas deer (Ozotoceros bezoarticus) fell enormously. In addition, negative impacts on the population numbers of small mammals have been documented in the Pampas since the 19th century and in Patagonia since the late 19th and early 20th centuries.

Changes associated with European colonization could indeed have led to the disappearance of the Argentinean Warrah. The cultivation of an area always entails ecological changes for flora and fauna: people need dwellings and arable land, and introduced cattle and horses need pastureland.

Prevosti also sees the domesticated dogs brought by European settlers as connected to the disappearance of the Argentinean warrah. Domestic dogs may have had a negative influence on the number of foxes as carriers of canine diseases such as rabies or distemper. Feral dogs certainly became food competitors. And hunting by the colonists—perhaps also with hunting dogs—is likely to have reduced the number of Argentinean warrahs.

Many causes lead to the extinction of a generalist

Medium-sized mammals, as the Argentinean warrah was, are actually generalists. This means that the animal species are only slightly specialized and have few or no environmental requirements. So how could pre-European and later European settlers, as well as environmental changes, have such a large effect on the Argentinean warrah as a medium-sized canid and generalist with omnivorous teeth and diet? Especially since other generalized canids, such as the coyote (Canis latrans) or the culpeo (Lycalopex culpaeus), even recorded rising population numbers and an expansion of their range in historical times.

The genetic material of the Argentinean warrah available to scientists today points to little genetic variability, according to Prevosti. This can result from a low population density or from a genetic bottleneck, which leads to severe genetic impoverishment because only a manageable number of individuals are present that can reproduce with one another.

This also fits the statement by the IUCN, which says that there were many fossil finds of the fox in various late Pleistocene sites, but hardly any fossil remains from the Holocene, and those only in the southern part of its actual range. If there were only a few genetically impoverished Argentinean warrahs left, the species must have been all the more sensitive to external threats. Ultimately, Prevosti considers it most likely that the disappearance of the Argentinean warrah was due to a combination of causes, brought about by humans and climatic changes.

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