May 19, 2009

Scientists Reveal Venomous Bite Of Komodo Dragon

Australian researchers have discovered what makes the Komodo dragon's bite so deadly for its prey.

Scientists previously considered that the world's largest lizard's mouth held deadly bacteria that stopped its victims' blood from clotting. Walter Auffenberg put that theory forward in 1981.

But lead researcher Bryan Fry used magnetic resonance imagery to show that the deadly lizard packs a venomous bite, as seen through its venom gland with ducts that lead to their teeth.

Fry used 3-D computer imaging to compare the Komodo's bite with the bite of the Australian saltwater crocodile, which has a skull of comparable size. His team found that the Komodo's bite is only one-sixth as powerful as that of the crocodile.

Imaging revealed that the Komodo used a pulling maneuver similar to the motion of the bite of a shark or saber cat.

The report, published in the Proceedings of the National Academy of Sciences, also found that other venomous lizards, including the Gila monster, were part of the same family as Komodo dragons. Additionally, venomous lizards and snakes appear to have descended from common origins.

"These lizards make a huge wound using their teeth; that's good enough to get the venom in," Christofer Clemente, a comparative physiologist at the University of Cambridge and a co-author of the study, told BBC News.

"They are robust enough that they can hang on to prey. Other groups like snakes are much more fragile - they have to bite something and let it go. So they have these hollow fangs and more deadly venom."

The venom is effective in killing victims by causing a sudden drop in blood pressure, resulting in shock and it also had an anti-clotting affect.

"Such a fall in blood pressure would be debilitating in conjunction with blood loss and would render the envenomed prey unable to escape," said Fry.

"These results are congruent with the observed unusual quietness and apparent rapid shock of prey items."


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