The tiny tree lizard only weighed 1.5 grams, almost a third of the larger common wall lizard's weight and a tenth of the gliding gecko's mass, so Aerts calculated how far each lizard would travel horizontally if they fell like a stone.

This time it was clear that the tiny tree lizard was travelling 20 cm further than Aerts would have expected if it were simply jumping off the platform.

The tree lizard was definitely delaying its descent and landing more slowly than the common wall lizard; the tree lizard was gliding.

But how was the tiny tree lizard able to remain airborne for so long? The team realised that instead of increasing its surface area to generate lift, the tree lizard is able to glide because it is so light.

Curious to find out why the tree lizard is so light, Herrel contacted Renaud Boistel, Paul Tafforeau and Vincent Fernandez at the European Synchrotron Radiation Facility to scan all three lizards' bodies, said an Antwerp release.

Visualising the animals' skeletons with X-rays, it was clear that the tree lizard's bones were packed full of air spaces, making the lizard's skeleton feather light for gliding.

These findings were published in the Thursday edition of the Journal of Experimental Biology.