Pterosaurs were flying reptiles. About 150 million years ago, this group of reptiles took to the air. Pterosaurs were light bodied creatures with leathery membranes stretched between their arms and forefingers to form wings. The first pterodactyls may have been gliders. Later, they may have developed the ability to fly by flapping their wings up and down. Some even fed on the wing. They plucked fish out of the sea in the manner of modern sea birds. Pteranodon was the largest of them. It had a wingspan of six metres. Pterosaurs are also known as pterodactyls.