The debate about whether dinosaurs were hot or cold-blooded animals has been with us for decades. A discovery that takes 65 million years in development. Now, new research led by Professor Haggit Affek of the Institute of Earth Sciences at the Hebrew University of Jerusalem suggests that prehistoric giants may have had the ability to regulate their body temperature, unlike today’s birds. which could change what we know about avian evolution.
The scientists used a new technique known as clustered isotope geochemistry to analyze the chemistry of different dinosaur eggshells, looking specifically at the composition of the carbon and oxygen atoms in them. Experts explain that by knowing the order of these atoms, it is possible to calculate the internal temperature of the mother at the time she laid her eggs.
What does the temperature say?
The researchers worked with fossilized eggs of three species of dinosaurs (each representing three major groups of dinosaurs): Troodon formosus, Maiasaura peeblesorum, and what is believed to be a dwarf titanosaur, which lived 69-75 million years ago at high altitudes. to make sure that body temperature was the result of an internal process and not the climate around them. Modern egg shells were also collected from cold-blooded invertebrates and warm-blooded bird species from the same areas in Alberta, Canada, and Romania to determine a reference temperature for egg layers in their local environment.
After looking at the fossils and comparing them with current ones, they concluded that the body temperature was between 35 ° and 40 ° C, close to the temperature of the human body (36.5 ° C – 37.5 ° C).
” Dinosaurs sit at an evolutionary point between warm-blooded birds and cold-blooded reptiles. Our results suggest that major groups of dinosaurs had warmer body temperatures than their surroundings,” says Research Associate Robin Dawson. postdoctoral fellow at the University of Massachusetts-Amherst and lead author of the study in the journal Science Advances.
“What we found indicates that the ability to metabolically raise their temperatures above the environment was an early and evolved trait for dinosaurs,” the authors clarify.
Hot blood?
The answer to the question has huge implications for science. Warm-blooded animals, also known as endothermic , can generate body heat, which makes them consume more energy, but also prepares them better against climate change, while cold-blooded animals, called exothermic, depend on the sun and require less energy and therefore less food.
As part of their evolution, it appears that at least some dinosaurs went from cold-blooded “terrible lizards” to warm-blooded avian dinosaurs. According to the researchers, the transformation had to happen very quickly.
Referencia: Eggshell geochemistry reveals ancestral metabolic thermoregulation in Dinosauria. Robin R. Dawson1, Daniel J. Field, Pincelli M. Hull, Darla K. Zelenitsky, François Therrien, Hagit P. Affek. Science Advances 14 Feb 2020:Vol. 6, no. 7, eaax9361 DOI: 10.1126/sciadv.aax9361
