Thursday, March 8, 2018

Falkland Islands Wolf (Dusicyon australis)

The Falkland Wolf (Dusicyon australis) was a medium-sized canid endemic to the Falkland Islands of South America where it was the largest terrestrial predator and the only mammal. It also has the unfortunate distinction of being the first canid to have become extinct in historic times. 

The name Dusicyon is derived from Greek and literally translates to “foolish dog”, a reference to the apparently bold and fearless nature of the animal when it first made contact with human settlers. The species name australis means “south”, a reference to the southerly location of the Falkland Islands. The full scientific name, therefore, means “Foolish Dog of the South”. Further denoting the islands to which it is endemic, the names “Falkland Islands Wolf”, “Falkland Islands Dog”, “Falkland Islands Fox”, or “Falkland Wolf” (as is used in this blog) have been used as a common name for this species. The name “Antarctic Wolf” has also been used due to the relatively close proximity of the Falkland Islands to Antarctica. Another common name, "Warrah", is a corruption of the Guarani (an indigenous South American language) word aguará, meaning "fox". It should be noted that the terms “wolf” or “fox” are colloquialisms and do not indicate a close relationship with these canids.

Habitat & Distribution
The ancestors of the Falkland Wolf colonized what are now the East and West Falkland Islands during the last glacial maximum, about 16,000 years ago. At that time, sea levels were lower and these islands were connected to the South American mainland. After sea levels rose at the end of the Pleistocene, these dogs became isolated on the newly formed islands located 400km east of southern Argentina. Falkland Wolves are known to have occurred in all the terrestrial habitats on these islands including rocky shrub, grassland, bogs, and marshland. 

The Falkland Islands. Wiki.

Physical Attributes
Falkland Wolves were medium-sized canids about the size of a Coyote (Canis latrans) or Black-backed Jackal (Canis mesomelas), although they were shorter and more powerfully-built than either. Adults ranged from 40 to 45cm (1.3 to 1.5ft) in shoulder height, 95 to 100cm (3.1 to 3.3ft) in head-and-body length, 28 to 30cm (0.9 to 1ft) in tail length, and 10 to 25kg (22 to 55lbs) in weight. The soft, thick coat was brownish-red in color with fine white speckling and white undersides. The tail was bushy with a distinctive white tip. The head was relatively broad with hypercarnivorous dentition. DNA analysis shows that Falkland Wolves share a common ancestor with the Maned Wolf (Chrysocyon brachyurus), a long-legged canid which hunts the tall-grass savannas of South America. The common ancestor of these two species existed about 6.7 million years ago, which predates the Great American Biotic Interchange. The probable direct ancestor of the Falkland Wolf is a mainland species called Dusicyon avus, which became extinct between 3,000 and 2,500 years ago. 

Falkland Island Wolf skull. Photo from Arkive.

Ecology & Behavior
Unfortunately, The Falkland Wolf was never formally studied, and so most aspects of its behavior are unknown. It may be inferred that, like other canids, they would have formed monogamous pairs with both adults caring for their offspring. It has been said to have inhabited burrows, another common behavior among canids. Interestingly, the Falkland Wolf was the only terrestrial mammal on the Falkland Islands, and had the unique distinction of being the only known canid to have been the largest predator of its environment. Due to the absence of rodents, its diet consisted mainly of ground-nesting birds such as gulls, penguins, and geese. It is also known to have fed readily on insects. On the beaches, it may have picked off dead or unattended seal and sea lion pups and also scavenged the carcasses marine animals.

When Charles Darwin first encountered the Falkland Wolf in 1833, he noted that the population was already in decline. He predicted that its extinction would be eminent with the arrival of permanent settlers to the Falkland Islands. He also claimed that the animal would be easy to kill by hunters due to its lack of fear of humans; it was the largest predator of its environment and thus did not need to fear anything short of another Falkland Wolf. Sadly, Darwin’s observations and predictions would later prove to be correct. As the number of visits to the islands increased during the 1800s, Falkland Wolf numbers began to noticeably dwindle, particularly with the arrival of fur traders from the United States in 1839. The final blow to this species came with the arrival of Scottish settlers in the 1860s. A huge poisoning campaign was launched due to an unfounded belief that the Falkland Wolves were a threat to livestock and the species was systematically eradicated. The last known Falkland Wolf died in 1876, just 43 years after Darwin's arrival.

No conservation measures were ever made to preserve the Falkland Wolf. It was deliberately eradicated. Today, thanks to the work of the Falklands Conservation Organization, the outlook for the islands’ other residents is far more positive and it is hoped that tragic extinctions such as this will never be repeated.

1890 illustration of Falkland Wolf. Artwork by John Gerrard
Keulemans Wiki.
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References & Further Reading
Sillero-Zubiri, C. 2015. Dusicyon australis. The IUCN Red List of Threatened Species 2015: e.T6923A82310440 <Full Article>

Francisco Prevosti F, Santiago F, Prates L, Salemme M, Martin F (2010). "Constraining the time of extinction of the South American fox Dusicyon avus (Carnivora, Canidae) during the late Holocene". Geophysical Research Abstracts, 12 (EGU2010-577-1) EGU General Assembly 2010 <Full Article>

Charles D (2000). Richard Keynes, ed. Charles Darwin's zoology notes & specimen lists from H.M.S. Beagle. Cambridge University Press. ISBN 978-0-521-46569-4. <Full Article>

Slater GJ, Thalmann O, Leonard JA, Schweizer RM, Koepfli KP, Pollinger JP, Rawlence NJ, Austin JJ, Cooper A, Wayne RK (2009). "Evolutionary history of the Falklands wolf". Current Biology 19(20): 937-938 <Full Article>

Lyras GA, Van Der Geer AAE (2003). "External brain anatomy in relation to the phylogeny of Caninae (Carnivora: Canidae)". Zoological Journal of the Linnean Society 138(4): 505–522. <Full Article>