Cows, deer, and elephants are just some of the animals that live together in groups, or herds. Fossil evidence suggests that some sauropods did the same thing. Sauropods such as Alamosaurus (AL-uh-mo-SOR-us) grouped together in small herds as young dinosaurs. As they grew, they either split up and went off on their own or stayed together with adults of the same age.

Sauropods probably lived in herds for a couple of reasons. Being in a group kept the animals safe, especially the small and young ones. Sauropods also probably had to migrate, or travel long distances, to find food, so they traveled as a group to stay safe and find it together.

Alamosaurus was the last sauropod dinosaur to have lived in what is now North America. It was the only sauropod to live at the same time and in the same place as T. rex.

Trackways
Scientists have studied fossilized footprints called trackways that show how sauropods moved. Some trackways show that one animal swayed as it walked and other dinosaurs around it followed the same trail. This is how scientists know that sauropods probably lived in herds.