A pterodactyl was a flying reptile that lived during the age of dinosaurs, roughly 150 million years ago. Despite what many people think, pterodactyls weren't actually dinosaurs: they were a separate group of reptiles that ruled the skies while dinosaurs walked the Earth below.

The name comes from Greek words meaning “winged finger,” which perfectly describes their most remarkable feature. A pterodactyl's wings were made of skin stretched between its body and one enormously long finger bone, similar to how a bat's wings work today. Some pterodactyls had wingspans as small as a sparrow, while others grew as large as a small airplane.

These creatures had hollow bones to keep them light for flying, sharp beaks for catching fish or small animals, and some species had dramatic crests on their heads. Scientists have found pterodactyl fossils all over the world, often near ancient coastlines where these reptiles would have hunted for food.

When people say pterodactyl, they often mean any flying reptile from the dinosaur era. Technically, Pterodactylus was just one specific type, but the name has become a catch-all term, like how people call all tissue “Kleenex.” The correct scientific term for the whole group is pterosaurs.