When the first warm-blooded dinosaurs roamed Earth

A new study suggests that the first warm-blooded dinosaurs may have roamed Earth about 180 million years ago. Scientists once thought of dinosaurs as sluggish, cold-blooded creatures. Then research suggested that some were warm-blooded — they could control their body temperature. But when and how that shift came about remained a mystery. Researchers studied climate models and over 1,000 fossils to come up with their estimate published Wednesday. They noted that two groups of dinosaurs migrated to colder areas during the Early Jurassic period, hinting that they may have developed the ability to regulate their body temperature.