Dinosaurs didn’t just summer in the high Arctic; they may have lived there year-round. That conclusion comes from new fossils of baby dinos.
Hundreds of bones and teeth from dino hatchlings turned up along the Colville River in northern Alaska. Their remains fell from rock on exposed hillsides. These fossils include remains of seven dinosaur families. Tyrannosaurs and duck-billed hadrosaurs were among them. There also were ceratopsids (Sehr-uh-TOP-sidz), known for their horns and frills.
“These are the northernmost [non-bird] dinosaurs that we know of,” says Patrick Druckenmiller. This paleontologist in Fairbanks works at the University of Alaska Museum of the North. And here’s why he finds the new fossils so special: They show some dinos did not just spend part of their year at polar sites. Here is evidence, he says, these animals were “actually nesting and laying and incubating eggs.” Keep in mind, he adds, this was “practically at the North Pole.”
The eggs of some of these species had to be incubated for up to six months, one 2017 study found. That would have left little time for any dinos nesting in the Arctic to migrate south before winter set in. That’s what Druckenmiller and his colleagues conclude in a June 24 report in Current Biology. Even if the parents could have made it south, they note, the babies would have struggled to survive such a trek.
The Arctic was slightly warmer during the dinos’ time than it is today. Some 80 million to 60 million years ago, the annual temperature there would have averaged about 6˚ Celsius (42.8˚ Fahrenheit). That’s not much different than modern-day Ottawa, the capital of Canada. Still, wintering dinosaurs would have had to survive months of darkness, cold temperatures and even snows, Druckenmiller observes.
It’s possible insulating feathers might have helped them fight the cold. The reptiles also might have had some degree of warm-bloodedness. And, Druckenmiller speculates, the plant eaters among them may have hibernated or eaten rotten vegetation when fresh food became hard to find over the dark months.
Finding these baby dino fossils unearthed more questions than answers, he admits. “We’ve opened a whole can of worms.”