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bodied dinosaurs covering at least seven different types – including duckbilled 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.

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, planteaters – must have formed entire communities that adapted to endure the challenges of extreme winter survival.”