Non-bird dinosaurs lived between about 245 and 66 million years ago—and during much of that time, another reptile group called pterosaurs ruled the skies. Just as there were lots of different dinosaurs, from tiny raptors to huge T.rex, there were hundreds of kinds of pterosaurs. They evolved into many shapes and sizes, and they filled lots of different roles in their ecosystems. Here are just a few of them.

The first pterosaur ever discovered by scientists, Pterodactylus antiquus, was on the smaller side. Its wingspan was only about three feet, making it about the size of a small hawk or falcon. These early scientists had never seen anything like a flying reptile, so they didn’t know what to make of it.

One thought it might have lived in the water and swum. Now we know that it used its wings for flight and probably flew over water, hunting fish. Pteranodon was a little like a big albatross bird that lives today. It used its wide wings (up to 20 feet from tip to tip) to soar over water, gliding on air currents so it didn’t waste energy flapping its wings.

I love flying with the big guys.

Some pterosaurs, like Quetzalcoatlus northropi, were the biggest animals ever to fly. Their wings stretched over 30 feet—around the length of a school bus! Since animals need to be light in order to fly, they had light hollow bones and small bodies.

Lots of animals have strange features that help them scare off predators or attract mates—including pterosaurs. Tupandactylus imperator had a huge snowy crest that was bigger than the rest of its head!