Climate change made dinosaurs evolve warm-blooded ones Sciences

You Dinosaurs had to face major climate changes Between 250 and 65 million years ago, due to high levels of volcanic activity. Now, a new study by scientists in Vigo, Spain, has looked at how some species have adapted to this: DrDevelopment of hot blood.

For a long time, paleontologists assumed that dinosaurs were ectotherms, that is, cold-blooded animals. This meant that they did not need as much food and their metabolism was stimulated by the sun and heat.

However, Cold-blooded animals depend greatly on the weather. Today's reptiles, fish and insects, for example, fall into this group and need exposure to sunlight to regulate their temperature.

It has been known for some time that the two Three large groups of dinosaurs were warm-bloodedThat is, they were endothermic, just like us, humans, and all other mammals and birds today.

Warm-blooded dinosaurs needed more food, but their metabolic rate was higher, making them less dependent on the elements. Since they were endothermic, they relied more on a regular supply of food.

The two groups of warm-blooded dinosaurs are called theropods (such as Velociraptor and Tyrannosaurus) – from which our modern birds descend – and ornithischians (such as Triceratops and Stegosaurus). The third group, called sauropodomorphs (such as brachiosaurs), were made up of very large dinosaurs with long necks – and these were cold-blooded.

Extreme climate change forced dinosaurs to adapt

Researchers at the University of Vigo wondered when and why groups of theropods and ornithischians evolved into warm-blooded animals. Through a large-scale analysis of dinosaur bones and their location, they discovered that at that time, 200 million years ago, climate change played a decisive role.

“We are not talking about climate change as we know it today, this change has occurred over thousands of years,” explains Rainer Schoch, a paleontologist at the Natural History Museum in Stuttgart who specializes in fossils of amphibious and terrestrial reptiles.

The causes of the strong climate fluctuations were the same as today: excessive carbon dioxide pollution in the atmosphere. But at the time, it was caused by volcanoes, which were much more active, releasing massive amounts of greenhouse gases into the atmosphere. Which made the weather unstable. At first, it cooled noticeably for several thousand years, and then became hotter.

Rainer Schoch explains that many species of cold-blooded dinosaurs became extinct during this period because they were unable to adapt to fluctuations.

Warm bloods enabled new habitats

The exact extent of temperature fluctuations at that time cannot be reliably reconstructed, according to Schoch. However, it can be assumed that the cold phases were relatively warm compared to today. The hot stages were hotter by today's standards.

During this period, two of the three main groups of dinosaurs evolved to become warm-blooded, a mechanism for adapting to climate fluctuations. “Warm-blooded animals were able to open new habitats toward the poles and find new places,” Schoch explains.

Without this development in blood, today's birds would not be able to fly. “The way birds fly requires a very high metabolism. Warm blood is an important prerequisite for this,” highlights Schoch.

Although they are cold-blooded, some species of the sauropodomorph group also survived. Due to their massive size and mass, they had a crucial advantage: gigantothermy, a phenomenon in which animals with large ectotherms find it easier to maintain a constant, relatively high body temperature than smaller animals.

“Climate impacts on wildlife are the most important thing we can take away from this,” Schoch asserts. “We don’t understand everything yet, but we will understand it better if we look to the past.”