The agamid genus Draco, also known as the Flying Lizard, is a gliding animal. Within Southeast Asia, there are many different species of Draco, but they all have the same physical adaptation of a patagium. A patagium is an extension of extra skin from the body that acts as a wing for gliding animals. What is unique about the patagium of the Flying Lizard is rather than extending from the arms to the legs, it is supported by ribs. The patagium is attached to dorsal thoracic ribs and these ribs are extended outward when the Draco glides.
Draco Sumatranus also known as the Common Flying Lizard http://terselubung.blogspot.com/2010/02/draco-sumatranus-naga-avatar-dalam.html
Like other gliding animal, the Flying Lizard uses gliding mechanics to get from tree to tree. It leaps from its high up location thus horizontally accelerating. From there, it extends its patagium. This creates lift, which increases with to air speed and is the force that counters gravity. Once enough lift is generated to counteract gravity a steady level glide can be achieved.
It has been observed that Flying Lizards have amazing maneuverability in the air. They have the ability to avoid obstacles mid glide, and they have even been observed pulling off barrel rolls. This ability comes from the fact that they have a flexible patagium and that they have precise control over the movement and bending of the patagium through contractions of the internal and external intercostal muscles as well as the external oblique muscles.
There are many different species of Draco. Research has shown that how these various species glide depends on their wing loading. The species with smaller wing loading have greater maneuverability because of better muscle control, and they have a wider range of potential glide angles allowing them to have a larger gliding range. The results of the research showed the larger species with wing loading greater than 16 N/m2 have glide angles ranging from 25-34 degrees compared to the smaller Draco whose glide angles ranged from 15-35 degrees. The larger species also have to jump from higher locations to generate greater velocity so they can have lift that is large enough counter their weight.
Overall the flying lizard is remarkable. Its flexible patagium that it is able to manipulate is an amazing piece of nature and something that scientist could use in developing flexible-winged aircrafts.
References:
Alexander, David. “Nature’s Flyers: Birds, Insects, and the Biomechanics of Flight”. page 46 (link to Google books); September 22, 2011
McGuire, Jimmy and Dudley, Robert, “The Biology in Flying Lizards(Genus Draco) and their Fossil Extant Analogs” Oxford Journals. September 22, 2011.
Dudley, Robert. McGuire, Jimmy.”The Cost of Living Large: Comparative Performance in Flying Lizards (Agamidae: Draco)” Web. September 22, 2011 [pdf]
“Gliding in Draco lizards and tree snakes” Map Of Life. Web. September 22,2011
2 Comments
Kevin Ma posted on September 24, 2011 at 1:59 pm
Are there any examples of flexible winged aircrafts?
Sam Nichols posted on September 24, 2011 at 4:38 pm
There are examples. A NASA engineer nambed Rogallo developed a a flexible glider to attach to a space capsule in the mid 1900s. This was so the capusle would approach Earth horizontally and vertically as opposed to only vertically. Hang gliders are built on this same model. But neither seem to have the level of precise control that the flying lizards has.