Fossil jaw unveils Ice Age dire wolves in Canada, rewriting history

"We could tell pretty clearly right away it was a member of the dog family, about the size of a wolf," Reynolds adds. Hence, it was either a dire or a grey wolf. They can be distinguished based on their teeth, but this animal was too old.

"When an animal gets really old, it starts to wear down its teeth, and this can mean that features of the teeth get worn away," Reynolds said.

They were bigger than grey wolves

Although dire wolves typically grow larger than grey wolves, this individual was within both species' normal size range. So the researchers tried a different approach. The scientists utilized a computer tool to assess the shape of the fossil by taking measurements along its outline. They compared it to values they knew from dire and grey wolves.

The northernmost confirmed specimen of the dire wolf ever discovered is this one. This is because a sizable ice sheet covered most of what is now Canada back then.

On the rolling, grassy plains around the South Saskatchewan River, where the dire wolf was discovered, it's hard to image an Ice Period bestiary. Still, every now and then, the ice withdrew, allowing habitat to reopen from Yukon down to central and southeast Alberta.

"Canadian fossils, especially from the time the after the dinosaurs, are relatively understudied," Reynolds said. "We're really just starting to figure out what the landscape looked like."

Study abstract:

The dire wolf (Canis dirus) had a broad geographic range in Pleistocene North and South America. Its northernmost occurrence has been reported from late Pleistocene deposits in Medicine Hat, Alberta, representing the only record of the taxon in Canada. However, the dentary upon which these reports were based has never been described or illustrated. The Medicine Hat specimen is badly crushed and appears to be from an old individual, which precludes the observation of adult diagnostic morphological characters. Geometric morphometrics were used to test the previous identification of the Medicine Hat dentary. A landmark-based principal component analysis and a canonical variates analysis suggests that the specimen more strongly resembles dire wolf specimens than grey wolf (Canis lupus). Identification of the Medicine Hat specimen as C. dirus supports it as the northernmost occurrence of this species in North America. However, we note the potential for allometric relationships that may confound differentiation between grey and dire wolves based on the morphology of the dentary. This study concludes by identifying future work needed in the areas of canid allometry and the biogeography of late Pleistocene North America and Beringia.