Dinosaurs are frequently pictured as living in tropical jungles and warm climates. However, current research refutes this notion: Instead, dinosaurs had to endure subfreezing conditions, which eventually allowed them to rule during the Jurassic.
Paleontologist Paul Olsen, the study’s lead author, traveled to China’s Junggar basin in 2016 in search of dinosaur footprints and fossils. Olsen’s team discovered something much coarser than sand and gravel on the first day, at the first stop. To Olsen, it seemed quite peculiar.
The research’s principal investigator, Olsen, told Mashable, “We didn’t move for three hours arguing about what this is.
“Everything we know about dinosaurs is backward. They are primarily creatures of the cold.”
The research team focused on “ice-rafted debris,” which are sediments with pebbles that formed around 206 million years ago, as the source of the mysterious deposits. (Ice built up in the water next to the land, eventually carrying and dropping rocks from the land lodged in the ice to the bottom of a lake.) Its presence in the area suggests that there was once floating ice in a region where dinosaurs roamed and left behind distinct footprints. The scientists also discovered that the Junggar basin was above the Arctic circle, which meant that it was very cold there, especially in the winter.
“Everything we know about dinosaurs is backward. Animals that are primarily adapted to cold climates “Olsen made a point.
Around 230 million years ago, during the Triassic Period, when Earth was still one single, enormous landmass known as “Pangea,” dinosaurs first started to emerge. Massive volcanic eruptions at the end of the Triassic period raised the planet’s temperature dramatically. Oceans became very acidic as carbon dioxide levels (which trap heat on Earth) shot up. The majority of species found these conditions to be unfriendly; according to the fossil record, three out of every four land and ocean species perished. However, dinosaurs managed to survive and go on to dominate the Jurassic period.
It’s unclear exactly how they were able to succeed.
However, Olsen’s research now provides an explanation: The chemical sulfur dioxide, which absorbs sunlight, was also released into the atmosphere during the same volcanic eruptions that emitted vast quantities of heat-trapping carbon dioxide.
This caused the Earth to dim and brought on “volcanic winters,” which were ten-year periods of extremely cold weather. Importantly, the temperature drops brought on by harsh volcanic winters were much greater than the rise in temperature brought on by carbon dioxide emissions.
In China’s Junggar basin, scientists discovered ice-rafted sediments, a definite indicator of a cold climate.
Paul Olsen is to blame.
Feather-like adaptation for surviving in the cold
Many unprotected land animals, especially those in the tropics, were unable to endure these severe cold snaps and perished, along with a crocodile-like species that was closely related to dinosaurs. But Olsen noted that the dinosaurs had a special adaptation that helped them survive.
Like birds, dinosaurs had insulation. Protofeathers, a feather-like structure that dinosaurs inherited from their ancestors, were similar to the feathers that protect birds from the cold. (However, the largest dinosaurs didn’t require feathery insulation because they were merely enormous and had high metabolic rates, according to Olsen, who spoke to Mashable.)
The study caught my attention because it presents a different historical narrative that contradicts the common perception of dinosaurs.
The dinosaurs, both herbivores and carnivores, eventually took control about 200 million years ago after their rivals were largely wiped out.
Herbaceous dinosaurs flourished during this time because of the success of plants that had adapted to the cold. “Herbivores were able to endure the winters due to the abundant vegetation. Naturally, that was food for the carnivores “Olsen clarified.
The discovery might alter how we perceive the dominance of dinosaurs during the Jurassic period. Anthony Fiorillo, a paleoecologist at Southern Methodist University who was not involved in the study, said “I thought the study was exciting because it’s another story from another time, that challenges the dinosaurian stereotype.” In particular, their insulation mechanism was very intriguing, according to Fiorillo, an expert on Arctic dinosaurs, who spoke to Mashable.
Dinosaurs likely also evolved to live in cold climates. According to Fiorillo, dinosaur growth may have been slower in the Arctic’s winter months than it was in the summer. Similar to tree rings, the fossilized bones have markings called “bone rings” that show when their growth temporarily ceased. As a result, the animals were able to conserve energy during the long winters when there was a shortage of food.
Olsen and his team intend to keep looking for the ice-rafted debris, which is the most convincing evidence that dinosaurs survived in colder climates. Follow along: It’s still being written how long the dinosaurs lived in our world.