Titanosaurs may be some of the biggest dinosaurs to have walked the earth yet they are the least understood. This diverse group of sauropod - Argentinosaurus, Paralititan and Saltasaurus are but a few - lived during the Late Cretaceous Period between 90 and 65 million years ago. So what makes this dinosaur family so interesting? The titanosaur thrived when other sauropod went extinct. Paleontologists think this group of sauropod adapted better than their cousins. Some titanosaur species traveled in herds providing a better defense against predators. Female titanosaurs laid their eggs together in an effort to protect their young. What's more, titanosaurs had a slightly different body than earlier species. They had long hind legs, a small, flat skull, and tough, bony plate built into their skin.