The question of whether the dinosaurs were cold-blooded or warm-blooded remains one of the main questions for researchers of these ancient animals. Dinosaurs, like modern reptiles, were believed to be cold-blooded creatures. However, more and more evidence of the opposite has been found recently: dinosaurs were warm-blooded, like their feathered descendants.
Another proof of the theory of warm-bloodedness of dinosaurs was the results of the analysis of chemicals contained in the fossilized shells of dinosaur eggs. "The results show that all major groups of dinosaurs had body temperatures higher than their surroundings," says geophysicist Robin Dawson of Yale University. "The ability to raise body temperature through metabolism was one of the characteristics of dinosaurs."
In their study, Dawson and her colleagues examined pieces of eggshell from dinosaurs that lived in Canada about 75 million years ago, including the large herbivore Maiasaura peeblesorum and the smaller bird-like Trooson formosus. They also examined the eggshell of a dwarf sauropod titanosaur found in Romania, which is estimated to be about 69 million years old.
Scientists have analyzed the chemical bonds in an ancient carbonate mineral found in egg shells. In particular, the atomic ordering of carbon and oxygen isotopes in the molecular lattice indicates the temperature at which the material is formed. In other words, the body temperature of the mother dinosaur that laid the eggs.
Dinosaur eggshell cross section under a microscope using cross-polarized light..
It was found that the temperature of the bodies of the dinosaurs was higher than the ambient temperature. In other words, they were endothermic (capable of internally generating heat), unlike exothermic animals, which receive heat from the environment.
Tests have shown that the temperature of eggs during their formation was 3-6 degrees Celsius (in some cases 15 degrees Celsius) higher than the ambient temperature, which is the most convincing evidence to date that dinosaurs are warm-blooded.
“Members of the three main lines of dinosaurs had elevated body temperatures compared to ambient temperatures, suggesting that they had hereditary metabolic control over internal temperatures,” the researchers write in their paper.
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Kirill Panov