A Grinning Monster from the Past: Fossilized Canadian Dire Wolf Identified
In the basement collection of a museum in Canada, a jaw with sharp teeth belonging to a formidable creature lay hidden. This fossilized find belonged to a beast that once roamed the bluffs along the South Saskatchewan River, vying for supremacy with saber-toothed cats (Smilodon) in hunting horses, bison, camels, and mammoths.
Thanks to the efforts of researcher Ashley R. Reynolds at the Department of Natural History, Royal Ontario Museum in Toronto, this long-forgotten discovery was brought to light once again. Reynolds, taking advantage of new knowledge acquired since the time of the initial finding, decided to closely examine past specimens. This practice, which gained renewed popularity in collections worldwide during the pandemic lockdown, has led to fascinating discoveries, including Reynolds' recent publication in the Journal of Quaternary Science, unveiling the identification of the fossil as a Canadian dire wolf.
Previous investigations conducted by Reynolds and their colleagues had previously yielded the first-ever evidence of a Canadian saber-toothed cat (Smilodon fatalis) from the museum's collection. In their latest study titled "Dire wolf (Canis dirus) from the late Pleistocene of southern Canada (Medicine Hat, Alberta)," Reynolds further analyzed additional fossil material from the same excavation site, leading to the formal identification of a dire wolf based on a fossilized jaw bone in the museum's collection.
The fossil jaw bone was originally discovered in 1969 and was initially identified as a dire wolf by C. S. Churcher (who is also an author in Reynolds' paper) in an unpublished report to the Geological Survey of Canada in 1970, based on its large size. However, this identification was never confirmed as the fossil had not been previously illustrated or described in detail.
Dire wolves, which are extinct canids closely related to gray wolves but larger in size and possessing more robust jaws, once inhabited various regions ranging from North and South America to Eastern China. They were formidable competitors, as their territories often overlapped with other large predators, including saber-toothed cats that were three times their size.
The fact that the fossil jaw of the dire wolf in Canada remained unstudied for so long is indeed unusual, considering that it would be the first and only known occurrence of dire wolf in Canada and the northernmost known occurrence of the species by 500 km. It is possible that the initial observations lacked confidence for a more formal identification due to the specimen being an outlier in terms of its geographical location.
One of the challenges in distinguishing between a gray wolf and a dire wolf from poorly preserved fossils is that the two species are very similar morphologically, despite being separated by over 5.5 million years from their common ancestor. If the fossil jaw had been in better condition and preserved the distinct patterns on teeth surfaces, the identification would have been more straightforward, as the size and dental characteristics can clearly differentiate between the two species. However, the 1969 fossil was in a deteriorated state, with fractures and missing teeth that made it difficult to rely on obvious identifiers.
To determine the identity of the fossil jaw, the researchers took multiple measurements and compared them to known dire wolf fossils, modern-day gray wolves, and gray wolf ancestor fossils. Although there was some overlap with outliers between dire wolves and gray wolf ancestors in the analysis, the plotted measurements of the fossil jaw consistently placed it within the dire wolf category, as originally suggested in the 1970 unpublished report. Radiocarbon dating of wood pieces found near the jaw, believed to be from the same location, dated to around 45,000 years ago, providing further evidence for the dire wolf's presence in Canada during the late Pleistocene epoch.
This long overdue investigation expands the known range of territories where dire wolves once inhabited. The recent identification of a 40,000-year-old dire wolf fossil in Northeast China, mentioned in the study, suggests possible faunal migrations between Asia and North America during the timeframe of the Canadian dire wolf, possibly facilitated by land bridge formations during the last ice age. As dire wolves may have coexisted with early humans migrating into Beringia as recently as 9,500 years ago, it raises the possibility of interactions between dire wolves and early human populations in that region.
Source: Ashley R. Reynolds et al, Dire wolf ( Canis dirus ) from the late Pleistocene of southern Canada (Medicine Hat, Alberta), Journal of Quaternary Science (2023). DOI: 10.1002/jqs.3516