Komodo Dragon: Varanus komodoensis

Teresa Dang
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Varanus komodoensis. Left: captive at Chester Zoo, England, © Nicholas Hinks. Right: captive at Disney's Animal Kingdom, © Raul654.


Varanus komodoensis is the largest extant lizard on Earth and is endemic to several small islands in Indonesia.  The genus name, Varanus is the latinization of the Arabic word "waran" which stands for monitor (Egyptians believed these lizards served as monitors, alerting people to the presence of crocodiles).  Its common names include the "Komodo dragon" (Komodo is one of the islands they are found on), "ora" which means land crocodile in the Mangarrai dialect, and Komodo monitor.

History and Evolution

V. komodoensis share a common ancestor with dinosaurs, but do not descend from them.  Both V. komodoensis and dinosaurs belong to the subclass Diapsida which is branched into two infraclasses: Archosauria (dinosaurs, including birds) and Lepidosauria (tuataras, lizards, and snakes).  Fossil records show that around 100 million years ago, during the Cretaceous period, a species related to the present-day Varanidae appeared and reached Australia by about 15 million years ago.  From this species descended a second lineage which differentiated into V. komodoensis about 4 million years ago.

There has been much debate about how V. komodoensis evolved to be as large as it is, despite being isolated on small islands with limited resources.  One theory suggests that the presence of pigmy elephants or stegodonts selected for larger dragons.  The larger the dragon, the more capable it is of hunting large prey such as pigmy elephants.


The Komodo dragon was first documented in 1910 by Lieutenant van Steyn van Hensbroek who went to Komodo Island after hearing stories about giant lizards.   He killed a dragon and sent the skin and several photographs to Peter A. Ouwens, director of the Zoological Museum and Botanical Garden at Bogor, Java, who eventually determined that the dragon was a monitor lizard.  Several expeditions followed including an expedition led by W. Douglas Burden which captured 27 specimens and examined at least 70 individuals in 1926.

Physical Characteristics

The Komodo dragon is the world's largest extant lizard at an average length of 2.6 m and an average weight of 40-70 kg.  The dragons have sharp, curved claws and around 60 curved, serrated teeth with 4-5 replacement teeth at each position.  The serrations in the teeth help Komodos tear large prey into smaller pieces.  Bits of meat from their meals get caught between their teeth and the decay of these pieces promotes the growth of several highly septic bacteria.  The bacteria often cause the death of the prey by infection so even if the prey has escaped initially, if it has been bitten, it may end up as a Komodo's meal.  Komodo dragons are resistent to these bacteria, so a bite from another dragon would not cause death by infection.






V. komodoensis are found naturally on the islands of Komodo, Flores, Rinca, and Gilli Motang in the middle of the Lesser Sunda Islands in Indonesia.  All of these islands are volcanic.  There are two main seasons in the Lesser Sunda Islands: a moderate monsoon season (January to March), and a long dry season.  V. komodoensis are usually found in rocky valleys between 500-700m above sea level and frequently occupy regions between the tropical monsoon forest and the savanna. Hatchlings live in trees and feed on insects and smaller mammals, but medium to larger dragons live on the ground.


Komodo dragons are ectotherms and thus require a lot less food than mammals of similar size.  They dig dens to protect themselves from the heat of the sun and often dig in search of rodents, lizards, and snakes for food.  Digging is done using the fore legs: one leg digs several strokes and then the other. 

Rubbing behavior is often practiced by young Komodo dragons.  They rub their bodies in the hair or intestinal contents of carrion.  It is thought that being covered in feces would protect them from predation by larger dragons. 




Reproduction and Life Cycle

 Courtship and Mating

The hatching of Kraken in 1992. Kraken was the first Komodo dragon born outside of Indonesia. Photo by Jessie Cohen, © Smithsonian Institution.



Parthenogenesis (Virgin Birth)

Information on the Internet


Auffenberg, Walter. The Behavioral Ecology of the Komodo Monitor. University P of Florida, 1981. 20-309.

Ciofi, Claudio. 1999. "The Komodo Dragon." Scientific American 280(3): 84-91.

Diamond, Jared. 1992. "The Evolution of Dragons." Discover 13(12): 72-80.

Gary P. Burness, Jared Diamond, and Timothy Flannery "Dinosaurs, dragons, and dwarfs: The evolution of maximal body size" PNAS, Dec 2001; 98: 14518 - 14523.

Learning Information

About This Page
This treehouse was created as partial fulfillment for credit in the course ORIGINS 2FF3, Origins and Evolution of Organisms, offered by Jon Stone, Associate Director, the Origins Institute at McMaster University.

Teresa Dang
McMaster University

Correspondence regarding this page should be directed to Teresa Dang at

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