Komodo Dragon Bite Deadlier Than Thought

May 19, 2009

Here's a face you wouldn't want to stare into outside of this safe, virtual realm.

(Credit for all pics: Chris Kegelman)

The Komodo dragon lizard, seen above, causes its victims to die in a rather morbid way. After being pierced by the carnivorous reptile's sharp fangs, the hapless creatures go into shock before keeling over. Scientists at first thought poisonous bacteria in the Komodo's mouth did in prey, but now new research in the latest Proceedings of the National Academy of Sciences shows that a combination of the reptile's teeth and venom packs a deadly one-two punch.

"The view that the Komodo routinely kills using dirty oral bacteria is wrong," says research co-author, Dr Stephen Wroe from the University of New South Wales, Australia. "The dragon is truly poisonous. It has modified salivary glands that deliver both hypertensive and anti-blood-clotting agents, which, in combination with lightweight but sophisticated cranial and dental adaptations, allows it to kill large animals through rapid blood loss."

Wroe and his colleagues used computer modeling to analyze the Komodo dragon bite and found that dragons have much weaker bites than crocodiles of a similar size. However, magnetic resonance imaging revealed the dragons have complex venom glands as well.

After surgically excising the glands from a terminally ill dragon in a zoo, the researchers used mass spectrometry to obtain a profile of the venom, finding that the toxin was similar to that of the Gila monster and many snakes. The venom causes a severe loss in blood pressure by preventing blood clotting and widening blood vessels, thus inducing shock in a victim.

The researchers also examined fossils of the giant extinct dragon relative Varanus megalania and determined that this nearly 23-foot-long lizard was one of the largest venomous animals to have ever lived.

A member of the goanna family with ancestors dating back more than 100 million years, the Komodo dragon is the world's largest living lizard and inhabits the central Indonesian islands of Komodo, Rinca, Flores, Gili Motang and Gili Dasami. It grows to an average length of nearly 10 feet and weighs over 154 pounds. The reptile's unusual size is attributed to a phenomenon known as island gigantism, since there are no other carnivorous mammals to fill the niche on the islands where they live.

The lizards are apex predators and dominate the ecosystems in which they live. Although Komodo dragons eat carrion, they also hunt and ambush prey including invertebrates, birds, and mammals.

The dragon's large size and fearsome reputation has made it a popular zoo exhibit since Western scientists first brought it to world attention in 1910. In the wild its total population is estimated at 4,000 to 5,000. Its range has contracted due to human activities and it is listed as vulnerable by the International Union for Conservation of Nature.

Due to these new findings about Komodo dragon venom, this Animal Planet video could use revising, but there's some eye-catching footage in it nonetheless. 

Comments

[GMC]

Wow, I got a much better perspective of the Komodo Dragon than I had before. The picture along side of a water buffalo really shows how enormous the "lizard" is. I had no idea.

[Jennifer Viegas]

A 154-pound lizard does merit a second look. Thanks for stopping by, GMC.