Game of Thrones' Dire Wolves Turned Out to Be Genetically Different From Their Modern Relatives

10:10, January 20, 2021

UrFU scientists pubished an extensive analysis on dire wolves' evolution

49 researchers from nine countries studied the genome of dire wolves - large (about 68 kg) wolf-like canines, predators of the American megafauna of the late Pleistocene. It turned out that dire wolves were a common species in North America and became extinct about 13 thousand years ago. It is likely that dire wolves have lived in isolation in North America for a very long time, which is why they began to genetically differ from gray wolves or coyotes.

The research results are published in the journal Nature.

“Dire wolves are considered one of the most common and widespread large predators in Pleistocene America. Despite the abundance of fossils of these wolves, relatively little is known about their evolution or extinction, ”says Pavel Kosintsev, co-author of the work, senior researcher at the Institute of Plant and Animal Ecology of the Ural Branch of the Russian Academy of Sciences, leading researcher at the Laboratory of Natural Science Methods in Humanitarian Research, Ural Federal University.

Despite their overall phenotypic similarities, grey wolves and coyotes survived the Late Pleistocene megafaunal extinctions whereas dire wolves did not. One possible reason may be that both grey wolves and coyotes possessed greater morphological plasticity and dietary flexibility, thus allowing them to avoid extinction and become the dominant terrestrial predators in North America.

To reconstruct the evolution of dire wolves, scientists have sequenced five genomes from fossil remains (from Wyoming, Idaho, Ohio and Tennessee) dating back 13-50 thousand years ago. The results of the study showed that although dire wolves were very similar to modern wolves, the two branches diverged widely about 6 million years ago. There is no evidence of gene mixing between dire wolves and North American gray wolves or coyotes. This suggests that dire wolves evolved in isolation from the ancestors of these species in the New World, while the ancestors of gray wolves and coyotes evolved in Eurasia and colonized North America only relatively recently.

“Like other large North American carnivores such as the American lion and the giant short-faced bear, dire wolves survived to the end of the Pleistocene,” explains Pavel Kosintsev. “Despite general phenotypic similarities, gray wolves and coyotes survived the megafauna extinction in the late Pleistocene, while dire wolves did not. One possible reason could be that both gray wolves and coyotes had greater morphological and ecological plasticity, which allowed them to avoid extinction and become the dominant land-based predators in North America. On the other hand, gray wolves and coyotes could survive thanks to their ability to interbreed with each other and with other canines."

According to Pavel Kosintsev, as a result of such crosses, North American gray wolves have acquired a number of new features. In particular, increased immunity, which could help them resist certain diseases. It is likely that reproductive isolation prevented dire wolves from acquiring traits that would enable them to survive during the Holocene.

Dire wolves (Canis dirus, which means "formidable dog") hunted large mammals such as bison and horses. The sharp evolutionary difference between dire wolves and grays allows them to be attributed to a completely different genus - Aenocyon dirus. The dire wolves became widely known after the release of the series "Game of Thrones".