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Komodo Dragon's Bite Is "Weaker Than a House Cat's"

Carolyn Barry
for National Geographic News
April 18, 2008
 
The world's largest living lizard, the fearsome Komodo dragon, has a bite weaker than a house cat's, researchers say.

Though known for killing prey much larger than itself, the Komodo relies on its razor-sharp teeth, strong neck muscles, and "space frame" skull to subdue its prey, according to a new study.

Using computer models, researchers from Australia's University of New South Wales analyzed a Komodo specimen from the Australian Museum in Sydney.

Measuring the forces and composition of the lizard's skull, the researchers found that its jaw is not designed for crushing.

"The bite is really quite incredibly weak for such a big lizard—less than you'd expect from the average house cat," said Stephen Wroe, an author of the study, which was recently published in the Journal of Anatomy.

If a Komodo actually tried to crush prey with its jaws, like crocodiles do, "it would break its own skull," he said.

The Komodo dragon, a type of monitor lizard, can grow up to 10 feet (3 meters) long and is native to the Indonesian islands that include Komodo and Flores (see map).

Listed as a vulnerable species by the World Conservation Union, about 4,000 to 5,000 Komodos remain in the wild.

Still a Precision Killing Machine

Despite its flimsy bite, the researchers said, the Komodo has other physical traits in its favor that make it an able predator.

"What's really interesting is that it has a lightweight skull and weak jaw, but it has optimized the way the skull structure and material is arranged," Wroe said.

Likening the lizard's skull to the design of a bridge, Wroe said its "space frame" structure "uses minimal amounts of material to resist forces."

The computer model showed that the skull of the giant lizard varies in density.

Some sections are composed of spongy bone, giving it an elasticity that, not unlike a snake's jaw, allows the Komodo's mouth to open wider. It also gives leverage to its sharp, serrated teeth.

"This system appears beautifully adapted to bite and pull, so when it bites and pulls together it requires less force than if it was to bite and not pull," Wroe said.

Maneuvering its shark-like teeth, flimsy skull, and strong neck muscles in concert, the Komodo dragon "uses its head like a can opener," he added.

"It opens up major and traumatic wounds, and the prey dies of blood loss."

It's this precise killing method, called inertia eating, that allows the lizards to take down much larger prey, including wild pigs, deer, and buffalo.

"It has a more efficient way to kill larger animals than a cat does," Wroe said.

From Dragons to Dinosaurs

The findings confirm what zoologists already know about Komodo dragon behavior, said Peter Harlow, a reptile specialist at Sydney's Taronga Zoo.

(See a photo of a baby Komodo dragon hatched by "virgin birth.")

"We didn't expect that [lizards] would have big, crushing jaws, but no one's ever really studied it in detail, so it's good that someone's quantified it."

"You can use the same technology and apply that to animals that are no longer living," said the study's lead author, Karen Moreno, also from the University of New South Wales.

The researchers are now working on analyzing the bite of the Komodo's ancient relatives: dinosaurs such as the Allosaurus and Giganotosaurus.
 

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