This is Scientific American’s 60-Second Science. I'm Christopher Intagliata.Just like cows, sheep and bison roam in herds today, so, too, did plant-eating dinosaurs.And it appears they began flocking together much earlier than we used to think―just as the Jurassic period was beginning to unfold.(This is) a critical time in the evolution of dinosaurs.(This is) pretty early on. So the idea is: this type of social behavior, may actually contributed to the evolutionary success of dinosaurs.Jahandar Ramezani of the Massachusetts Institute of Technology is a geochronologist. In his words ...I date things. And I date old things, things in the millions and billions of years―not the really young stuff.In this case, Ramezani was dating tiny zircon crystals, in fact,in a fossil bed in Patagonia, near the southern tip of South America.Those crystals dated back to nearly 193 million years ago.And the fossils preserved there―an array of nearly 200 specimens of a plant eater named Mussaurus patagonicus―provide a snapshot of the dinosaur at all stages of its life.Eggs and hatchlings, clumps of juveniles and then―further out―adults.So this kind of undisturbed distribution of fossils and this kind of age segregation basically shows these dinosaurs had a social structure.They lived in a colony. And everybody has got things to do―duties―with respect to the young and the juveniles.
