Dire wolves were one of the most common large predators of Late Pleistocene North America, and sub-fossils of this species are common, but scientists have had difficulty finding specimens with enough intact DNA to analyze. There are thousands of dire wolf fossils excavated from the La Brea Tar Pits in California, but this DNA is contaminated with tar and can’t be used. There are also many specimens of dire wolf fossils from Florida, but the humidity there causes DNA to deteriorate and become unusable. However, Angela Perri, a zooarchaeologist from Durham University, made a concerted effort to find dire wolf specimens with enough viable DNA to study, and she found 5 specimens. Labs from Australia and England analyzed the DNA from these specimens and came to a stunning conclusion–dire wolves were not closely related to gray wolves (Canis lupus) as most paleontologists had assumed, and they were not really even wolves. Instead, they were the last in a lineage of now extinct ancient canids.
The genetic study determined the ancestor of dire wolves diverged from the ancestor of gray wolves at least 5.7 million years ago. The closest living relative of the dire wolf is the African jackal (C. mesomelas), but the ancestor of that species diverged from dire wolf ancestors about 5.1 million years ago. Interestingly, jackals can interbreed with wolves, but the study of dire wolf DNA found no evidence of interbreeding between gray wolves and dire wolves. Apparently, the 2 species had been geographically isolated from each other for too long, and when they came into contact did not recognize the other as possible sex partners. This study casts doubt on my hypothesis that an extinct ecomorph of Beringian gray wolves were a gray wolf/dire wolf hybrid. (See: https://markgelbart.wordpress.com/2016/05/30/beringian-wolves-an-extinct-ecomorph-of-canis-lupus-lived-as-far-south-as-wyoming/ )
Paleontologists assumed dire wolves were close relatives of gray wolves because their anatomy was so similar. Dire wolves had broader skulls, bigger teeth, shorter limbs, and were more robust; but otherwise they were much alike. The similarity can now be attributed to convergent evolution when unrelated species evolve similar traits in response to similar environmental conditions.
Canids originated in North America, but the ancestors of gray wolves, coyotes, and jackals colonized Eurasia and Africa and evolved separately from dire wolves whose ancestors remained in North and South America. (Dire wolves ranged from Alberta south to Peru and from California east to the Atlantic Coast.) Dire wolves appear suddenly in the fossil record 200,000 years ago. Most paleontologists think they evolved from Armbruster’s wolf (C. arbrustrei). No scientist has considered the possibility, but maybe this line evolved from the bone-eating dogs (Borophagus), a group of canids that seemingly disappeared early during the Pleistocene. Scientists can’t investigate this because no viable DNA from Borophagus dogs remains viable. Dire wolves were adapted to live in climates ranging from temperate to sub-tropical. Scientists weren’t able to sequence the entire genome of the dire wolf to determine its appearance, but they may have had shorter more reddish coats than gray wolves and probably preferred warmer climates. The ancestor of gray wolves and coyotes crossed the Bering Land Bridge and colonized North America at least 20,000 years ago and overlapped with dire wolves for about 10,000 years. Gray wolves co-evolved with humans and learned to fear man. Dire wolves never learned to fear man, and likely could not compete with humans. I think this explains their extinction, while wolves and particularly coyotes continue to hang-on.
The authors of the new study think dire wolves are so different from gray wolves they should be given a separate genus name–Aenocyon. One of the first paleontologists who looked at dire wolf bones assigned this genus name to dire wolves, but it fell from fashion because of the misconception that dire wolves were close kin to gray wolves. Turns out he was right; later paleontologists were wrong.
Reference:
Perri, A.; K. Mitchell, L, Frantz; et. al.
“Dire Wolves were the Last of an Ancient New World Canid Lineage”
Nature 2021
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