An illustration of oviraptorid theropods. Photo by Doyle Trankina and Gerald Grellet-Tinner
LOS ANGELES, Oct. 13 (UPI) -- Scientists have long debated whether dinosaurs were warm-blooded and quick-footed or cold-blooded and mostly sluggish, like modern reptiles like crocodiles and alligators.
New research suggests scientists can determine the body temperatures of ancient dinosaurs by analyzing the fossilized eggs they left behind. In applying the new research technique, scientists at UCLA say ancient eggs show some species were warm-blooded enough to move around much more quickly than modern gators.
The new method relies an in-depth scientific understanding of how eggshells form. The temperature at which shells of calcium carbonate form affects the organization certain carbon isotopes.
Because the biology of egg formation in modern birds and reptiles is largely the same as it was in egg-laying dinosaurs millions of years ago, researchers were able to analyze correlations between carbon isotopes in egg shells and the internal body temperatures of bird and reptile species.
When researchers realized they had created a formula that correctly predicted the temperature of the animals from which the eggs came from, they applied their science to fossilized dinosaur eggs.
Their findings showed that the eggs of long-necked sauropod dinosaurs formed at temperatures of approximately 100 degrees Fahrenheit. Eggs laid by smaller theropods called oviraptors formed at roughly 90 degrees Fahrenheit.
Geologic evidence suggests the dinosaurs' body temps were slightly warmer than their climate's average temperature of 79 degrees Fahrenheit.
"This could mean that they produced some heat internally and elevated their body temperatures above that of the environment but didn't maintain as high temperatures or as controlled temperatures as modern birds," lead researcher Robert Eagle said in a press release. "If dinosaurs were at least endothermic to a degree, they had more capacity to run around searching for food than an alligator would."
The new research was published in the journal Nature Communications.