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Credit: Andrey Atuchin

Dinosaurs roamed the arctic, and this newly unearthed bone can tell us how they thrived there

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Jul 13, 2020, 1:27 PM EDT

The prehistoric Arctic seems to have always had an Ice Age stereotype of being trampled by things like woolly mammoths and saber-toothed cats, but before those creatures ever existed, there were dinosaurs. That’s right. Dinosaurs.

Around 70 million years ago, dinosaurs had no problem with perpetual winter. The Prince Creek Formation in what is now Alaska has the largest deposit of dinosaur bones ever. Among those fossils, paleontologists found the only known fragment of bone from a dromaeosaurid (a Velociraptor relative). Most bone scraps like this end up overlooked, because they do nothing for dinosaurs that have been studied much more thoroughly — the ones whose skeletons you’re likely to encounter in a museum. There is so little known about dromaeosaurids in this region that this otherwise unimpressive piece of jawbone revealed incredible things.

“This is the first confirmed non-dental fossil specimen from a member of Dromaeosauridae in the Arctic,” said Alfio Alessandro Chiarenza, who led a study recently published in PLOS One, adding that “the juvenile nature of this individual adds to a growing body of data that suggests Cretaceous Arctic dinosaurs of Alaska did not undergo long-distance migration, but rather they were year-round residents of these paleopolar latitudes.”

Theropods like dromaeosaurids that lived in the Arctic have not left behind nearly enough fossils to tell scientists how they survived in such an unlikely area. It is believed they ended up there after migrating from Asia. The evidence that this yet-unnamed dinosaur was a juvenile reveals that dromaeosaurids were not only running around far up north, but also breeding. When something breeds on repeat, it thrives. 

What Cretaceous forests in the paleo-Arctic probably looked like. Credit: Andrey Atuchin

The problem is that the bones of these raptor-like reptiles are so fragile that not many have survived on the fossil record. Their bones were birdlike and hollow, giving these light-footed creatures the speed to run after prey in ancient riverside pine forests whose floors were overgrown with giant ferns.

Because dinosaur teeth are more likely to survive being fossilized and embedded in stone for tens of millions of years, scientists were previously able to get an idea of what lived in the Arctic during the Cretaceous period. There was a vague knowledge of dromaeosaurids previously because of the teeth they left behind. Just a piece off the tip of the jaw told Chiarenza’s team more about the anatomy of this dinosaur than they could have imagined, since its morphology aligned with that of raptor relatives and theropods in general. Tooth remnants in the fragment also echoed specimens of teeth from both and gave away that this dinosaur was a juvenile.

“[Teeth] confirm[ed] the presence of the group in areas for which purely osteological remains are unknown,” Chiarenza said.

What the team still aren’t sure about is whether this particular species could fly; dromaeosaurids are close to birds in an evolutionary sense, and it certainly had the bones for flight. They feel it probably stayed grounded (though it still could have been feathered). Whether or not it could fly, it probably didn’t migrate. Carnivorous dinosaurs and mammals are not believed to have engaged in such behavior, which is why the scientists believe that the evidence of breeding seen through this baby shows that these paleo-lizards were doing just fine where they were. Herbivorous mammals that lived in the Arctic were more likely to go through seasonal migrations than anything else.

After this, those Santa-saurus cards that emerge around the holidays are going to seem just a little more real.