Science has known since the 1950s that dinosaurs also lived in the Arctic. But it has long been thought that the animals would go south in the winter and back in the summer—like many of today’s migratory birds. But the discovery of fossilized events now indicates that at least some species spent the entire year in the polar latitudes and gave birth and raised their offspring there. Here’s what a group about Patrick Druckermiller from the University of Alaska North Museum reports in Current Biology..
Druckermiller and Co excavated hundreds of teeth and tiny bones just a few millimeters in size in the Prince Creek Formation in northern Alaska. The team was able to identify a total of seven species of dinosaur that died in the egg or after hatching. The area was outside the Arctic Circle more than 70 million years ago. To reach the regions to its south, dinosaurs had to travel at least 3,000 kilometers: on foot, scientists assure.
So they assume that the species in question remained at the site all year long and thus also during the long polar night. The incubation period for dinosaurs was estimated to be five or six months. If they had laid eggs in the spring, the young would not have hatched until autumn: in view of the long migration, it is too late. It is unlikely that they would have survived this. Alternatively, the animals would have already incubated in the winter, so that the offspring could gather enough strength for the long cold season during the summer.
Evidence for the presence of dinosaurs at this fossil site is by far the northernmost. Petrified trees from that time indicate that conditions were not quite as icy as they are today. However, the animals had to survive the long cold polar night. In the time of the dinosaurs, the area was ten degrees farther than it is today.