The first vertebrates to fly took to the skies about 215 million years ago. These creatures were neither birds nor bats. They belonged to a group of flying reptiles called pterosaurs. Pterosaurs ranged from the size of a sparrow to a small airplane, and are still the largest animals that ever flew. Along with dinosaurs and many other species, pterosaurs went extinct about 65 million years ago.

Image credits: main image, Sean Murtha.