Dire wolves not only featured in Game of Thrones, they were also real creatures, and hundreds of thousands roamed the American landscape up until the last ice age. A research project, published today, involving archaeologists from Oxford and around the world, shows though the fearsome dire wolf shared many characteristics with grey wolves, they were an evolutionary distinct species that separated from other canines about five million years ago.
Dire wolves were ubiquitous in America, along with a range of massive creatures, known as megafauna. These included mastodons, six-foot-tall sloths, enormous short-faced bears and beavers the size of compact cars. They disappeared from the continent in a mass extinction during the Pleistocene period – only for some, such as horses, to be reintroduced by Europeans in the last few hundred years.
The megafauna’s extinction was only around 13,000 years’ ago. In archaeological terms, compared to the 65-million-year-old dinosaur extinction, this is very recent, so much so that a ‘Pleistocene Park’ of towering megafauna may one day be a possibility.
Previously, it was thought dire wolves must be closely related to grey wolves, because the two species’ remains are almost indistinguishable and they had lived alongside each other. But, the team has established that the two species evolved separately - to become very similar creatures.
This challenge of extracting and sequencing DNA from these amazing extinct canids required an international effort. Thanks to the concerted diligence and expertise of the near 50-strong team, dozens of remains of dire wolves were located and examined, mostly without success. But the close collaboration was able to generate partial genomes from five specimens found in the United States, which had sufficient DNA to be of use in the study.
Nuclear DNA testing established that they had evolved separately from other canids. Intriguingly, despite the fact that genome analyses demonstrated that many other canids can and do hybridise, the study found no indication of matings between dire wolves and any other canid species. This may explain in part why they went extinct and why other North American canids, such as wolves and coyotes, survived the extinction.
According to Professor Greger Larson, head of Oxford’s Palaeogenomic and Bio-Archaeology Research Network, ‘There was a lot of failure before the team was successfully able to sequence a dire wolf. Being able to generate ancient nuclear DNA was a real coup, which revealed how dire wolves were related to all other canids. Armed with these genomes, maybe one day our grand-children will be able to see dire wolves in person.’
Professor Larson praised the international effort involved in the project and, in particular, the part played by early career researchers: ‘The scale of this collaboration, with so many young academics taking the lead, has been a joy to be a part of.’