Dinosaurs also thrived in the Arctic

published on Saturday, June 26, 2021 at 6:46 a.m.

Dinosaur species had made the Arctic their permanent home, and probably developed techniques like hibernation or feathers to survive the cold, according to a new study.

The work, published this week in the journal Current Biology, is the result of more than a decade of excavation to extract fossils, and undermines the idea that these reptiles only lived in milder latitudes.

“Some of the new sites discovered in recent years have revealed some amazing things, namely bones and teeth of baby” dinosaurs, senior study author Patrick Druckenmiller of the university told AFP. of the Alaska Museum of the North.

“It’s amazing, because it shows that these dinosaurs weren’t just living in the Arctic, they were able to reproduce there as well,” he continued.

Scientists first discovered dinosaur remains in 1950 in a region long considered too hostile to harbor reptiles.

Two competing hypotheses had then been formulated: either the dinosaurs lived there permanently, or they migrated to the Arctic and the Antarctic in order to take advantage of seasonally available resources, and possibly to reproduce there.

This new study is the first to show evidence that at least seven species of dinosaurs were able to breed at these extremely high latitudes – in this case the Prince Creek Formation in Alaska, between 80 and 85 degrees north latitude, dating from the Upper Cretaceous.

Species discovered include hadrosaurids, called duck-billed dinosaurs, horned dinosaurs like ceratopsians, and carnivores like tyrannosaurs.

The team of researchers found small teeth and bones, some of which are only a few millimeters in diameter, belonging to dinosaurs that had just hatched or died just before.

“They have a particular type of texture on their surface and very specific – they are very vascular, and the bones grow very fast, they have a lot of blood vessels running through them,” explained Patrick Druckenmiller.

Unlike other mammals like caribou, whose offspring can travel long distances almost immediately after birth, even the largest dinosaurs gave birth to cubs that would have been unable to cope with migrations of several thousand. of kilometers.

– Down jacket with feathers –

“We think of dinosaurs in these kinds of tropical environments, but the whole Earth was not like that,” recalls Patrick Druckenmiller.

The Arctic was warmer then than it is today, but conditions were still very demanding.

The annual temperature was around 6 ° C, but much lower temperatures were the order of the day, with snowfall, during the winter months.

This area was probably covered with conifers or ferns.

“We now know that most of the carnivorous dinosaurs that were there probably had feathers,” said Patrick Druckenmiller. “You can think of it as their own down jacket, to help them survive the winter.”

As for the smaller herbivores, researchers believe they would bury themselves underground and hibernate.

And the older ones, with more fat reserves, relied on lower quality twigs and bark to get through the winter.

On the other hand, the fact that dinosaurs stayed in the Arctic all year round is further clue to the idea that dinosaurs were warm-blooded animals, as other recent studies have suggested. They would then represent a point of evolution between cold-blooded reptiles and warm-blooded birds.

Their ability to survive the arctic winter is “the most convincing evidence so far” that they can be added to the list of species capable of thermoregulation, concluded Gregory Erickson of Florida State University and co-author of the study.


Sea ice in the Arctic is melting much faster than expected

When investigating the Arctic, researchers came to a frightening result: the thickness of the sea ice there is decreasing significantly faster than previous models have shown. This has serious consequences for the climate.

Photo series with 11 pictures

British climatologists have sounded the alarm in a new study and warned of dramatic ice melt in the Arctic. The sea ice thickness in the coastal regions of the Arctic is decreasing 70 to one hundred percent faster than generally assumed, according to the study published on Friday in the specialist magazine “The Cryosphere”. The sea ice in the Arctic keeps the earth cool – its disappearance would therefore exacerbate climate change from the point of view of scientists.

“From our point of view, our calculations are a huge step forward when it comes to the more precise interpretation of data from satellite data,” said co-study author and professor at University College London (UCL), Julienne Stroeve. According to the scientist, the affected Arctic region is warming three times as much as the earth as a whole.

Determination using satellite data

To determine the thickness of the sea ice, scientists measure the part of the ice that protrudes from the ocean. However, the values ​​are distorted by the snow that lies on the clods and pushes them down. For their study, the UCL researchers said they used more up-to-date satellite data from the European Space Agency (ESA) than were used in previous studies and combined them with calculations from a new climate model that they had developed together with US scientists from the University of Colorado.

“Previous measurements of sea ice thickness were based on a snow map that was last updated 20 years ago,” said PhD student and lead author Robbie Mallett. “Because the sea ice started to form later in the year, the snow on top of it has less time to pile up,” he said. The study presented by him and his colleagues takes this phenomenon into account for the first time. The result is that “the sea ice is thinning out faster than we thought”.

Sea ice thickness as an important indicator

The sea ice thickness is an important “indicator of the health of the Arctic,” stressed Mallett. Thick layers of sea ice served as a type of thermal insulation that prevented the Arctic Ocean from warming the earth’s atmosphere in winter. In summer, the floes protected the ocean from solar radiation. “Thinner ice also has a poorer chance of survival during the Arctic summer melt,” said Mallett.

The melting of ice in the Arctic is also fueling geopolitical tensions in the region, as neighboring states see opportunities for the development of previously unused resources and the potential for new sea routes in the disappearance of the floes. At a meeting of foreign ministers at the end of May, eight countries bordering the polar region, including the USA and Russia, agreed on peaceful cooperation to combat global warming.