They have long periods of winter darkness, freezing temperatures and often scarce resources, but a number of small fossils suggest that it wasn’t just dinosaurs that roamed. Arctic Pole, but also hatched and raised her children there.
While dinosaur fossils have previously been found in the Arctic, it’s unclear whether they lived there year-round or were seasonal visitors.
Experts now say hundreds of tiny dinosaur fossils found from northern Alaska indicate a breeding ground for creatures in the area, suggesting it was their permanent home.
The find is similar to a prehistoric maternity ward, said Professor Gregory Erickson, a paleontologist at Florida State University and a co-author of the study, adding that it was extremely rare to find dinosaur remains as small as they were so small and delicate.
“We were amazed when we found these little fossils,” he said. “We suspect they are nesting in the Arctic, but we didn’t expect to find evidence of this behavior.”
Writing in the journal Current Biology, Erickson and colleagues report how they analyzed fossils recovered from the Upper Cretaceous Prince Creek Formation in a decade-long series of expeditions that involved the use of fine-mesh sieves to sift through sediment.
Although there are dinosaur remains previously in formation, no evidence of reproduction has been shown.
But new research has revealed the discovery of tiny teeth and bones from tiny dinosaurs, including those that were about to hatch or have just hatched.
The fossils date back about 70 million years, and belong to dinosaurs large and small that included at least seven different species – including beaked and horned dinosaurs. Teeth were also recovered from a small dinosaur, perhaps as young as six months old, Erickson said.
“We’ve gathered evidence to suggest that not only were dinosaurs nesting there, but they appeared to be nearly all of them, if not all of them,” he said.
While the results rule out the idea that dinosaurs only moved north after breeding, Erickson added that the young that hatched at the Arctic would be too young to travel south in winter.
“Given the long incubation period, small hatch size, and short Arctic summer, dinosaurs were unlikely to have migrated,” he said.
The team says the conclusion that dinosaurs may have lived in the Arctic all year is supported by other evidence, including that many species are not found in rocks of the same age at low latitudes.
At the time dinosaurs roamed the Arctic, the area lacked significant polar ice caps and contained coniferous forests, but researchers say the creatures still faced harsh conditions, with continuous darkness for up to 120 days of winter and average annual temperatures. average. Just above 6 degrees Celsius.
The team wrote that “dinosaurs, if they were winter dwellers, tolerated freezing winter conditions with occasional snowfall.”
The study raises questions about how dinosaurs adapted to winter, Erickson said, with the team suggesting that smaller dinosaurs may have hibernated, perhaps in burrows, while larger herbivorous dinosaurs may have remained silent — despite plants such as bark, ferns and ferns. algae may have provided some of them. food.
Feathers may have provided some isolation, the team said, while the discovery of Arctic dinosaurs — but not cold-blooded creatures like amphibians or turtles — adds support to the idea that at least some dinosaurs were warm-blooded..
Dr Stephen Brusatte, a paleontologist at the University of Edinburgh who was not involved in the study, said the study was groundbreaking, adding that although the fossils are small, their significance is significant.
“Some of these fossils are the size of a pinhead or dandruff, and the fact that they survived the rigors of petrification is absolutely remarkable,” he said.
Brusatte added that research shows how well dinosaurs were able to adapt to survive in such harsh environments.
“For me that’s what amazes me the most,” he said. “These dinosaurs—large and small, carnivorous, and plant-eaters—must have formed entire communities adapted to meet the challenges of surviving the harsh winters.”
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