Reptiles
Flying Dragon
Draco volans · also called flying dragon, common flying dragon, gliding lizard
The flying dragon is a lizard the length of a pencil that has turned its rib cage into a pair of wings. It cannot flap, but it can spread those skin-covered ribs, step off a tree trunk, and sail 30 metres to the next one — then fold the wings away and become an ordinary-looking little lizard again.
Overview
Flying dragons (genus Draco, 40-plus species) live on tree trunks in rainforest, forest edges, and plantations across Southeast Asia. Draco volans is one of the most widespread. The lizard spends almost its whole life clinging to bark, hunting the ants and termites that stream over it, and rarely touches the ground.
Wings made of ribs
Five to seven pairs of the lizard’s ribs are enormously elongated and hinged to swing outward, with a membrane of skin stretched between them. To move between trees it launches, snaps the wings open, and glides, steering with its long tail and small neck flaps and flaring to land on a trunk. Gliding costs it roughly 2 metres of height per 10 metres travelled. At rest the ribs fold back and the wings vanish against its flanks.
Why glide
For a finger-sized lizard high in the canopy, the alternative — down one trunk, across the open ground, up the next — is slow and dangerous. Gliding crosses gaps in seconds, keeps the lizard in the canopy, and doubles as an instant escape: step off into the air.
Colour flags
Males carry a bright yellow throat flap (dewlap) and blue neck flaps, waved with head-bobs and push-ups to defend a tree and court females — a deliberate flash of colour from an animal that is otherwise well camouflaged. Females briefly come to the ground to bury their eggs, guard them for about a day, then return to the trees.
Status
Draco volans is Least Concern and common in suitable forest across its range.
Flying Dragon: common questions
How does the flying dragon fly?
It does not fly under power — it glides, like a paper aeroplane with steering. Five to seven pairs of its ribs are enormously elongated and hinged so they can swing outward, and a membrane of skin (the patagium) stretches between them. To glide, the lizard launches from a tree trunk, snaps the ribs out to deploy the wings, and sails to another trunk, using its long tail and small neck flaps as control surfaces to steer and to flare for landing. When it is not gliding, the ribs fold back and the wings lie flat and almost invisible against the body, so a resting flying dragon looks like an ordinary small lizard.
Why does it glide instead of just climbing down and up?
For a lizard the size of a finger living high in tall forest, moving between trees the long way — down one trunk, across the dangerous ground, up the next — is slow and exposes it to ground predators such as snakes and birds. Gliding lets it cross a gap in seconds and stay in the canopy the whole time. It also makes escape easy — a threatened flying dragon can simply step off into the air. The lizard spends almost its entire life on tree trunks, hunting the ants and termites that run over the bark, and only the females come down, briefly, to lay eggs.
What are the bright flaps on its throat and sides for?
They are signalling structures, most developed in males. The flying dragon has a large, brightly coloured throat flap called a dewlap or gular flag — usually vivid yellow — plus a pair of flaps at the sides of the neck. A male extends and waves these, often combined with head-bobbing and push-ups, to defend his patch of tree from other males and to court females. Because the lizard is so well camouflaged when still, these flashes of colour are also a way of being seen deliberately when it wants to be. Different Draco species have different flag colours and patterns, which helps keep them reproductively separate.
Is the flying dragon dangerous or venomous?
Not at all. It is a tiny, harmless insectivore with no venom and a bite that could not break human skin. It is shy, fast, and hard to catch, and it is not kept much in the pet trade because it is difficult to keep alive in captivity — it needs a tall enclosure, lots of vertical space and live ants, and does poorly otherwise. In the wild it is completely benign and is a favourite sight for visitors to Southeast Asian forests when one launches off a trunk and sails away.