Nearly 200 years after Charles Darwin wondered how a fox-looking wolf came to live on South American islands hundreds of miles from the mainland, scientists think they have the answer.
The Falkland Islands wolf, the only land animal believed to have occupied the Falkland Islands before it was hunted into extinction in the 19th century, trekked to its final home over ice sheets during the last ice age, researchers concluded.
The wolf, Dusicyon australis, became isolated from its sister species, Dusicyon avus, on the South America mainland about 16,000 years ago, according to the study published Tuesday in Nature Communications. The predator likely followed its food source: penguins, seals and sea birds.
Scientists traced the wolf’s ancestry by studying its four-legged relatives in South America. The team studied the DNA of six distinct Dusicyon avus teeth between 3,000 and 7,800 years old and genetic makeup from nearly every extinct and living species of South American canid.
When they compared that with the evolution of avus teeth, they determined that the Falkland Islands wolf diverged 16,000 years ago. The wolf’s teeth are larger and sharper than that of its relatives, the scientists wrote.
They found that divergence matched the last glacial maximum date, when sea levels were hundreds of feet lower than they are today. Researchers wrote that they could not rule out that the wolf species was transported there by humans on boats. But, the team said, it’s “highly improbable” because of the timing of humans in the region and the species’ development.
Researchers determined it was an ice sheet instead of a land bridge because no other land mammals appear to have crossed, meaning it was likely only a temporary path. Or, the team wrote, other animals on the island left no fossil record.
The study is available here.
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