Dinosaurs lived in the Arctic, research suggests

Discovery of tiny fossils indicates dinosaurs raised young in freezing region – and may have been warm-blooded

It had long stretches of winter darkness, freezing temperatures and often scarce resources, but an array of tiny fossils suggests dinosaurs not only roamed the Arctic, but hatched and raised their young there too.

While dinosaur fossils have previously been found in the Arctic, it was unclear whether they lived there year-round or were seasonal visitors.

Now experts say hundreds of fossils from very young dinosaurs recovered from northern Alaska indicates the creatures reproduced in the region, suggesting it was their permanent home.

Prof Gregory Erickson, a palaeobiologist at Florida State University and a co-author of the research, said the discovery was akin to a prehistoric maternity ward, adding it was very rare to find remains of such young dinosaurs because they are so small and delicate.

“We were stunned when we discovered the tiny fossils,” he said. “We suspected they were nesting in the Arctic, but didn’t anticipate recovering evidence of this behaviour.”

Prof Gregory Erickson, left, and his colleague find evidence of baby dinosaurs in the Arctic.
Prof Gregory Erickson, left, and his colleague find evidence of baby dinosaurs in the Arctic. Photograph: University of Alaska Fairbanks and Florida State University

Writing in the journal Current Biology, Erickson and colleagues reported how they analysed fossils recovered from the Upper Cretaceous Prince Creek Formation in a series of expeditions spanning a decade and involved the use of fine mesh screens to sift sediments.

Though remains from dinosaurs have previously been found in the formation, none showed evidence of reproduction.

But the new research has revealed the discovery of tiny teeth and bones from young dinosaurs, including those who were just about to hatch or had recently done so.

The fossils, dating to around 70m years ago, came from large and small-bodied dinosaurs covering at least seven different types – including duck-billed and horned dinosaurs. Teeth were also found from a young tyrannosaur, said Erickson, possibly just six months old.

“We have built up a body of evidence that showed not just one of the dinosaurs was nesting up there, but it looks like almost all of them, if not all of them,” he said.

While the findings rule out the idea that dinosaurs only moved north after reproduction, Erickson added that young hatched in the Arctic would have been too small to travel south for the winter.

“Given long incubation periods, small hatching sizes, and the short Arctic summer, it is very unlikely the dinosaurs were migrating,” he said.

The team said the conclusion that the dinosaurs likely lived in the Arctic year-round is backed up by other evidence, including that many of the species have not been found in rocks of a similar age at lower latitudes.

Some of the fossils found in the Arctic are the size of dandruff flakes.
Some of the fossils found in the Arctic are the size of dandruff flakes. Photograph: University of Alaska Fairbanks and Florida State University

At the time that dinosaurs roamed the Arctic, the region would have lacked big polar ice caps and had conifer forests, but the researchers say the creatures still faced harsh conditions, with up to 120 days of continuous darkness in the winter and an average annual temperature of just above 6C.

The team wrote that “the dinosaurs, if winter residents, endured freezing winter conditions with occasional snowfall”.

Erickson said the study raised questions of how the dinosaurs coped in the winter, with the team suggesting smaller dinosaurs may have hibernated, potentially in burrows, while larger herbivorous dinosaurs may have fasted – although plants such as bark, ferns and moss may have provided some food.

The team said feathers may have provided insulation, while the discovery of dinosaurs in the Arctic – but not cold-blooded creatures such as amphibians or turtles – adds support to the idea that at least some dinosaurs were warm-blooded.

Dr Stephen Brusatte, a palaeontologist at the University of Edinburgh who was not involved in the study, said the research was groundbreaking, adding that while the fossils are tiny, their importance is huge.

“Some of these fossils are the size of pinheads or dandruff flakes, and the fact that they survived the rigours of fossilisation at all is remarkable,” he said.

Brusatte added the research showed how adaptable dinosaurs were to survive in such a harsh environment.

“That to me is what is most stunning,” he said. “These dinosaurs – big ones, small ones, meat-eaters, plant-eaters – must have formed entire communities that adapted to endure the challenges of extreme winter survival.”

Contributor

Nicola Davis Science Correspondent

The GuardianTramp

Related Content

Article image
Two-legged dinosaurs may have swung tails to run faster, say scientists
A computer simulation could help us better understand the evolution of movement in animals

Linda Geddes

22, Sep, 2021 @5:00 PM

Article image
Large dinosaurs migrated huge distances, say scientists

An analysis of dinosaur teeth suggests the creatures may have migrated from flood plains to uplands during the dry season

Ian Sample, science correspondent

26, Oct, 2011 @5:00 PM

Article image
Dinosaurs had feathers ruffled by parasites, study finds
Ancient pieces of amber found to contain dinosaur feathers riddled with louse-like insects

Nicola Davis

10, Dec, 2019 @4:00 PM

Article image
Giant Jurassic fleas drank the blood of dinosaurs and pterosaurs
Fossils unearthed in China reveal that the insects were up to 10 times as large as modern fleas

Ian Sample, science correspondent

29, Feb, 2012 @6:09 PM

Article image
Fossil remains of herd of 11 dinosaurs discovered in Italy
Exceptional find includes biggest and most complete dinosaur skeleton ever unearthed in the country

Angela Giuffrida in Rome

02, Dec, 2021 @6:13 PM

Article image
Answer to fossil record puzzle may lie with teenage T rexes, study finds
Absence of smaller dinosaurs may be result of adolescent megatheropods crowding them out

Linda Geddes

25, Feb, 2021 @7:00 PM

Article image
Scientists digitally reconstruct skulls of dinosaurs in fossilised eggs
Research on Massospondylus carinatus embryos sheds new light on animals’ development

Nicola Davis

09, Apr, 2020 @10:32 AM

Article image
'Thunder thighs' dinosaur had a devastating kick, say scientists

The newly discovered dinosaur Brontomerus mcintoshi may have used its huge muscular thighs to kick predators and rivals

Ian Sample, science correspondent

23, Feb, 2011 @7:30 AM

Article image
Sabre-toothed, ferret-like mammal unearthed in Patagonia

The discovery of an extinct mammal called Cronopia will help scientists track the emergence and spread of mammals

Alok Jha, science correspondent

02, Nov, 2011 @7:01 PM

Article image
Bizarre dinosaur reconstructed after 50 years of wild speculation
Deinocheirus mirificus, or ‘unusual horrible hand’, had long, clawed forearms, a sail on its back and a duck-like bill

Ian Sample, science editor

22, Oct, 2014 @5:00 PM