How do flying lizards glide through the air?

It is important to clarify that while they are commonly called "flying lizards," these animals are actually expert gliders rather than true flyers.1

Flying lizards of the genus Draco glide by utilizing specialized anatomical structures. Their "wings" consist of folds of skin supported by five or six elongated ribs that extend laterally from the body between the forelimbs and hind limbs. When at rest, these ribs and skin folds are tucked against the lizard's sides; however, when the lizard prepares to glide, it opens these ribs like a fan to increase its surface area and catch the air.12

To move between trees in their native Southeast Asia and the East Indies, these lizards launch themselves from a perch and glide toward another tree. Just before landing, they turn upward sharply to slow their momentum, allowing for a controlled arrival on the new surface. Because their limbs remain unmodified, they retain the ability to walk and run like other arboreal reptiles when not in the air.1