A ‘lost world’ of dinosaurs thrived in the snowy dark of Alaska

Paleontology can be pretty grueling work, especially if you want to study dinosaurs who could handle snow.

To get to the Prince Creek Formation of Alaska - an area rich with fossils of creatures who lived in the ancient Arctic - scientists have to wait for things to thaw. Then they have to come in on tiny bush planes and take inflatable boats down rivers plagued by crumbling cliffs. If they make it to the dig site without a plane crash or a cascade of boulders, they're in for freezing rain, snow and hordes of mosquitoes - not to mention bears, wolves and other dangerous predators.

They endure all this for a single month of field work. It would be a tad longer if not for falcon nesting season.

"The falcons do dive bomb us pretty frequently," Florida State University professor Greg Erickson told The Washington Post.

But for Erickson and his colleagues, it's worth it. To them, this part of Alaska is the last frontier of dinosaur discovery. Along with Patrick Druckenmiller, earth sciences curator of the University of Alaska Museum of the North and associate professor of geology at the University of Alaska Fairbanks, Erickson has just announced the discovery of a new species of dinosaur found in the area.

But the duck-billed dino is even more exciting than your usual find. The dinosaur, which was previously believed to belong to a well-known species, was incredibly abundant around 70 million years ago. They've already found some 10,000 bones from the species.

And that means that it thrived in an area that was - at least for a dinosaur - remarkably cold.

"It wasn't so long ago that the idea of dinosaurs living up in the polar world was kind of, you know, really? Are you kidding?" Druckenmiller said. We don't know a ton about how dinosaur metabolisms worked (in fact, debate over whether they were warm- or cold-blooded still rages), but most people think of them as fairly tropical creatures, like modern lizards.

It's an intriguing question, and one that's difficult to answer with bones alone: Did dinosaurs, like modern reptiles, need to bask in the sun and heat to survive? Or were they warm-blooded, like the birds that would become their only surviving descendants - able to survive in the cold and dark? Erickson and Druckenmiller's new species shows that the answer may be quite complicated.

The new species, called Ugrunaaluk kuukpikensis, is described in a study published Tuesday in Acta Palaeontologica Polonica. At 25 feet long, the plant eater looked very similar to Edmontosaurus, a duck-billed dinosaur frequently found in Alberta and Montana. But the abundant bones, which the researchers believe are gathered in one place because a herd of young dinosaurs were attacked, showed enough small differences to make them suspicious. Detailed analysis by Hirotsugu Mori, a former graduate student at UAF, helped confirm that this was a new creature.

At the time that these dinosaurs lived, their region would have averaged temperatures in the low 40s. "By reptilian standards, that's pretty chilly," Druckenmiller said. So he and his colleagues believe that this species must have had special adaptations to live in the cold.

"These were dinosaurs living at the very edge of what we think dinosaurs were physiologically capable of," he said.

Erickson added that these extreme conditions created a sort of "natural laboratory." If the team can figure out how U. kuukpikensis was different from its close cousins in balmier regions, they might figure out how the new species managed to survive the cold.

The researchers are particularly interested in looking at how quickly the new species grew, which could tell them whether it used an unusually slow metabolism to manage the cold. They can track growth rates by looking at lines of arrested growth in the dinosaur bones, which are basically the same as the rings in a tree.

In addition to cold and occasional snow, the dinosaurs also endured darkness: The region would have been dark for three to five months a year, and there's no sign that the dinosaurs migrated to get some sun. The researchers already have evidence of at least 13 species of dinosaurs taking up permanent residence in this inhospitable place, and they expect to find even more - including a few unknown species.

"It's intriguing for us to ponder how they survived those months of darkness," Erickson said. "We're just finding this whole new world of dinosaurs we didn't know existed."