Dinosaurs Likely Started Living in Herds About 190 Million Years Ago; Formed Groups Based On Age, Body Size

After studying the fossils, found in a sag basin in southern Patagonia (Argentina, South America), scientists concluded that the occurrence of many fossils of dinosaurs at different life stages within a square kilometre suggests they lived in herds nearly 190 million years ago (the fossils have been dated to 192 million years ago).