The Triassic Period

The Triassic Period lasted from about 252 to 201 million years ago. It was the beginning of the Age of Dinosaurs. The first dinosaurs appeared during this time, but they started out small. The Triassic began right after the worst mass extinction in history.

After the Great Dying

Before the Triassic, the Permian extinction wiped out 90 percent of all species. Life had to start over. The first dinosaurs appeared about 230 million years ago. They were small, about the size of a dog. Other reptiles were still the dominant animals for much of this period.

A Hot, Dry World

During the Triassic, all the continents were joined together as Pangaea. Much of the land was hot and dry desert. The first mammals also appeared during this time, but they were tiny. The first pterosaurs took to the sky. By the end of the Triassic, dinosaurs were starting to take over.

Fun Facts

• The first dinosaurs were only about the size of a large dog.
• The Triassic got its name because its rocks were first divided into three layers in Germany.
• The first turtles and crocodile relatives appeared during the Triassic.

Did You Know?

One of the earliest known dinosaurs is Eoraptor, which was only about 3 feet long. It was found in Argentina and lived about 230 million years ago. It is hard to believe that tiny animals like this would eventually evolve into giants like T. Rex!