Out of Bounds

Dire, but Not Exactly Wolves

Dire wolf skeletal remnants suggest the big dogs were quite similar to modern gray wolves

By Rob Breeding

I’m fascinated by extinct megafauna, those large, charismatic animals that roamed North America near the end of the Pleistocene Epoch until about 13,000 years ago, when many went extinct.

That extinction event claimed one of my favorite ancients, the dire wolf, which we know through a rich fossil record. These skeletal remnants suggest the big dogs were quite similar to modern gray wolves, many of which roam today’s northwest Montana — too many in the opinion of some.

Dire wolves were bigger and brawnier than gray wolves. The dire’s jaw bones were so stout some suggested they were bone crushers, like the oversized hyenas they competed with for Pleistocene big game.

I don’t know who these spoil sports are, with their soul crushing speculation, but they seem to relish in destroying our most fevered fantasies of ferocious, ancient predators.

Dire wolves surely scavenged, as do modern wolves. The dire’s bulky jaw packed extra bone crushing power, and anyone who has enjoyed roasted bone marrow — canoe cut, please — can attest to its rich deliciousness. Though no self-respecting predator passes up a chance to crack open a femur and nosh, that bulky dire wolf jaw seems primarily designed to kill the mega megafauna that shared its world.

Still, the bones are so similar paleontologists sometimes mix them up. This became important when researchers went looking for dire wolf remains from which they could extract DNA. The bulk of dire wolf fossils were collected from the La Brea Tar Pits in Los Angeles. The Tar Pits preserved a wealth of bones from the Pleistocene, but that bubbly vat destroys DNA.

In some far-flung museums, staff misidentified wolf fossils. A reexamination of those old bones revealed some came from dires, and from those bones, uncooked by tar, researchers pieced together complete DNA.

And that DNA revealed the wolves weren’t closely related kissing cousins after all.

Instead, it appears dires broke off the canid family tree about 5.5 million years ago, according to a story just published in National Geographic. This suggests dire wolves evolved on their own, in the new world, then travelled back to Asia while early modern wolves were simultaneously spreading the other way.

The two species shared North America for some time, likely thousands of years, but it doesn’t appear they interbred the way modern wolves, coyotes and domestic dogs sometimes do.

The similarity between the two great wolves is another example of convergent evolution. It seems there is some grand design — an archetype of how the largest canid predator is put together — whether that evolution occurred in North America or the Eurasian landmass.

Sadly, until someone invents a working time machine, wolf researchers can’t directly observe dires in their natural habitat. Without that behavioral data we’ll never know for certain how dire wolves went about their daily business.But we can still glean much from the behavior of modern wolves.

Dire wolves likely hunted in packs so they could take down their much larger prey. Following the mass extinction event, which wiped out three quarters of Pleistocene megafauna, dire wolves may have been too specialized as hunters of the biggest big game to adapt to the new order.

Catastrophe usually takes with it the specialists. In catastrophe’s wake, generalists often thrive. It’s really no wonder scientists call our current geological age the Anthropocene Epoch, meaning the time when humans are the primary influence of climate and environment.

Humans. We’re not always charismatic, but our general adaptability seems limitless.

Rob Breeding is the editor of www.mthookandbullet.com.

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