Draco Lizards and Flying Dragons: Strange Reptiles
Strange and Interesting Reptiles
Draco lizards are strange and interesting reptiles that have folds of skin on each side of their bodies. When the skin folds are extended they look like wings. These "wings" enable the lizards to glide for long distances in their forest habitat.
Draco lizards are also known as flying or gliding lizards or, in the case of some species, as flying dragons. The scales covering a lizard's body and the fact that the animal seems to have wings remind some people of a dragon. In fact, draco is the Latin word for dragon.
There are over forty species of Draco lizards, all of them native to Southeast Asia. They are classified in the family Agamidae. Members of this family are often referred to as agamids or agamid lizards.
In this article, the term "Draco lizards" refers to all animals in the genus Draco. This article focuses on Draco volans, also known as the common flying dragon, and Draco mindanensis, also known as the Mindanao flying dragon. It also includes a few facts about other lizards in the genus.
Draco volans: The Common Flying Dragon
The scientific name of the animal known as the common flying dragon (or simply the flying dragon) is Draco volans. The term "flying dragon" is sometimes used for other Draco lizards, but I'll use it to refer to Draco volans.
Flying dragons are tiny reptiles, unlike their mythical counterparts. They have slender bodies and reach a length of eight inches or a little longer. The lizards have a very long tail compared to the length of the rest of their body.
The species is found on the islands of Java and Bali in Indonesia and possibly in other areas. Some forms that were once considered to be subspecies of Draco volans have been moved to their own species, however, which can be confusing. The animal lives in the trees and catches insects to eat. In some countries, it's bred as a pet. As might be imagined, keeping an animal built for long-distance movement content in captivity could be difficult.
Physical Appearance of the Flying Dragon
Like many Draco lizards, common flying dragons have a mottled appearance. They are generally a mixture of grey, brown, black, and green in colour. Their colours help to camouflage them against the trunks of the rainforest trees.
The scientific name for the wings is "patagia" (or patagium when one wing is being discussed). The upper surface of the patagia of flying dragons has a mottled or banded black, grey, and brown pattern. It also has yellow or orange pigment. The amount of this pigment varies. The patagia of some Draco lizards have very colourful upper or lower surfaces.
Flying dragons have a loose flap of skin called a dewlap or gular flap hanging below their neck. Like the wings, the dewlap can be extended. The male has a yellow dewlap while the female has a smaller, blue-grey one.
Patagia or Wings and Gliding Ability
A flying dragon's wings extend from just behind the front legs to just in front of the back legs. The last five to seven of the animal’s ribs are elongated and extend into the wings. Muscles attached to the ribs cause the ribs to move and the wings to unfurl like an opening fan when the animal wants to glide. Research suggests that in at least some cases the "hands" of the lizard's forelimbs grab hold of the wings to help them unfurl.
The lizard has a smaller wing, or lappet, on each side of its neck. When the lappets are extended to the side, they act as mini-wings that help the animal to glide.
Some reports state that flying dragons can glide as far as sixty metres (just under two hundred feet), or even further, and that they lose one foot in height for every five feet travelled through the air. Most glides seem to be around thirty feet, however.
The lizards have better control of their motion than other reptiles that take to the air, such as flying geckos and flying snakes (which are also gliders, despite their names). Flying dragons can move their patagia as they glide. They can also move their tail, which acts like a rudder for steering. The animals have a flattened appearance while they are gliding.
The lizard in the video below is the southern flying lizard or Draco dussumieri. The species is found in southern India and has the most westerly distribution of all of the Draco lizards. The animal in the video demonstrates how the colour, patterns, and protuberances on its surface can camouflage the lizard.
Life in the Trees
Flying dragons are active during the day. They glide from one tree to another, or sometimes from one branch to another in the same tree, in order to find food or a mate or to escape from predators.
Males also glide to chase away other males. A male patrols a territory of a few trees, gliding around the trees to protect them from invading lizards. When the males land, they often flash their dewlaps to advertise their territory. Unfortunately, this makes their presence more visible to predators. The animals do have one advantage over many of their predators, though—the ability to take off into the air and control their direction with precision.
When they’re not gliding, the lizards often travel rapidly up and down tree trunks and along branches. They may also stay motionless for a while, becoming very hard to see as they blend in with their background.
Small lizards tend to live lower in the tree canopy than larger ones. When the heavier animals take off from a tree they need to develop speed before they extend their wings to glide. Starting their journey from a higher point helps them to do this.
Diet and Predators
Most of a flying dragon's diet consists of ants, but it also catches termites and other insects. The lizard often feeds as it ascends a tree trunk. A male very rarely—if ever—comes to the ground. A female comes to the ground to lay her eggs, however.
It's thought that the lizard's chief predators are arboreal (tree-living) snakes, large birds, and monitor lizards. Despite the presence of their predators, though, most flying dragons are very successful in their habitat.
There is still much to be learned about the lives of flying dragons in the wild, including information about their reproduction. Researchers know that the animal has an interesting mating display. During courtship, the male displays his dewlap and his wings to attract females and also bobs his body up and down.
After mating, the female digs a hole in the ground with her snout. She deposits up to five eggs in the hole, which she covers with soil. She guards the eggs for about a day and then leaves them on their own. The estimates for the length of time between egg laying and egg hatching vary widely. The time likely depends on environmental factors.
The Mindanao Flying Dragon
The Mindanao flying dragon lives in the Philippines and has the scientific name Draco mindanensis. It's been found on the island of Mindanao and on neighbouring islands, but none of the populations seem to be dense. The animal is rarely seen and may have been uncommon for a long time.
The lizard's body is pale grey-brown in colour. The upper surface of the body has both large and small white spots. The dorsal or upper surface of the patagia is red with lighter spots and striations in the male and black with lighter areas and striations in the female. The dewlap of the male is an attractive orange colour. The female's is duller and has a cream or yellow tip.
Like other gliding lizards, the Mindanao flying dragon lives in the forest, eats insects, and is active during the day. It's found quite high on tree trunks. The lizard is larger than many of its relatives and can glide further and faster.
Population Status of the Lizards
The IUCN (International Union for Conservation of Nature) classifies animal populations according to their nearness to extinction. Unfortunately, the Mindanao flying dragon is classified in the "Vulnerable" category. In addition, the IUCN says that its population is decreasing.
The last population assessment for the Mindanao flying dragon was performed in 2007. A lot may have happened to the animal during the twelve-year gap between the assessment of its population and the present time. It's a shame that there hasn't been more emphasis are collecting new information for the sake of both the lizard and the other organisms living in its habitat.
The Mindanao flying dragon is threatened by deforestation. The IUCN says that forest disturbance is probably a threat as well. Efforts are being made to protect the animal's rainforest habitat, which will hopefully allow its population to grow or to at least stabilize.
The status of the common flying dragon population has been classified as "Least Concern" by the IUCN. In this case, the assessment was based on relatively recent data from 2017. The population trend for the animal is unknown, however.
Variable Patagia Colours
A confusing aspect of investigating Draco lizards is that the colour and/or pattern of the patagia of a species may vary. Researchers from the University of Melbourne and the University of Malaysia have made an interesting discovery related to this observation.
Dracus cornutus lives in Borneo. The scientists found that two populations of the species had patagia with different appearances and that the colours matched those of the falling leaves in the area. One population had red patagia, which matched the colour of the leaves falling in their coastal mangrove forest habitat. The other had green and brown patagia, which matched the colour of the falling leaves in their rainforest habitat located further away from the coast.
The researchers believe that the different colours help to camouflage the lizards and protect them from bird attacks as they glide. More research is needed to answer questions raised by the study, but the scientists have made some very interesting observations.
Some people think that Draco lizards are poisonous, but researchers say that this isn't the case. The animals are actually harmless to humans.
Draco lizards are unusual and fascinating little creatures. They are well adapted to their forest habitat and are fun to observe. A gliding lizard is a beautiful and often impressive sight, especially in the species with vividly coloured patagia.
Studying the animals could reveal new features of their biology and lives. In the case of the Mindanao flying dragon, it might also help us understand what is happening in the animal's environment and discover how to deal with the problems. This discovery could be beneficial for multiple species of wildlife. Hopefully we will be able to see Draco lizards on trees and moving between them for a long time to come.
Facts about the common flying dragon from National Geographic
Forelimbs and flight in Draco lizards from New Scientist
Information about the common flying dragon from the IUCN Red List
The amphibians and reptiles of MIndanao Island from ZooKeys (A Pensoft publication)
Mindanao flying dragon report from the IUCN Red List
The biology of gliding in flying lizards from Oxford University Press
Variation in the patagia colours of a species from the phys.org news service
© 2011 Linda Crampton