In the canopy of a Malaysian rainforest, a little lizard scuttles to the end of a branch and launches itself into the air. It doesn’t, however, fall to its doom. Instead, it extends two flaps of skin from its flanks, supported by unusually long ribs. The flaps look and work like wings, allowing this lizard—the aptly named flying dragon—to glide to safety. They are so adept in the air that they almost never come to the ground. Why bother, when they can travel for 20 to 30 metres between treetops, without losing much altitude?

There are 42 species of flying dragons, or Draco as they are formally known, and they all glide on extended flaps of skin or patagia. But