(NewsNation) — The first warm-blooded dinosaurs may have roamed the Earth about 180 million years ago, halfway through the creatures’ time on the planet, according to a new study.
The study, published in the journal Current Biology, suggests three main dinosaur groups adapted differently to changes in temperature.
Warm-blooded creatures — including birds, who are descended from dinosaurs, and humans — keep their body temperature constant whether the world around them runs cold or hot. Cold-blooded animals, including reptiles like snakes and lizards, depend on outside sources to control their temperature: for example, basking in the sun to warm up.
Knowing when dinosaurs evolved their stable internal thermometer could help scientists answer other questions about how they lived, including how active and social they were.
To estimate the origin of the first warm-blooded dinosaurs, researchers analyzed over 1,000 fossils, climate models and dinosaurs’ family trees. They found that two major groups of dinosaurs — which include Tyrannosaurus rex, velociraptors and relatives of triceratops — migrated to chillier areas during the Early Jurassic period, indicating they may have developed the ability to stay warm. A third crop of dinosaurs, which includes brontosaurs, stuck to warmer areas.
The Associated Press contributed to this report.