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It’s not their dirty mouths
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by tigers9 on May 18, 2009
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http://www.sciencenews.org/view/generic/id/43907/title/It%E2%80%99s_not_their_dirty_mouths
It’s not their dirty mouths
Komodo dragons kill prey with venom, not oral bacteria, study suggests
By Laura Sanders
Web edition : 2:00 pm
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DIRECT HITA new study shows Komodo dragons probably use venom, not toxic bacteria, to kill prey. IMAGE: Chris Kegelman
Add shock-inducing venom to the list of reasons to avoid Komodo dragons. The fierce lizard may kill its prey in a way similar to some snakes, researchers report online May 18 in Proceedings of the National Academy of Sciences. The finding contradicts the widely held notion that Komodo lizards rely on nasty bacteria and resulting infection to kill prey.
The world’s largest living lizards, Komodo dragons are fervent predators found only in Indonesia. The dragons are quick, strong and large (the largest reported was more than 10 feet long and weighed in at 366 pounds), and they can take down prey as large as deer. “These things are incredible killing machines,” says Bryan Fry of the University of Melbourne in Australia, who coauthored the new study.
Just how these deadly lizards kill has been controversial. Conventional wisdom held that after inflicting a bacteria-laden bite, the dragons would track wounded prey and wait days for sepsis to set in before dining.
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Scientists recently discovered Komodo dragons possess six venom glands on each side of the lower jaw. Bryan Fry, et al.
“In the minds of many biologists, that just didn’t make sense,” comments Christopher Shaw, a biological chemist at Queen’s University Belfast in Northern Ireland. “If you’ve evolved to be the size of a Komodo dragon, it seems to be a waste of time.”
What’s more, rare sightings of the lizards hunting didn’t fit with this method. Victims typically died quickly and quietly after going into shock, the authors say. “No one’s actually seen a Komodo dragon track a prey for three days until it dies of septicemia,” Fry says. “It’s an absolute fairy tale.”
And though the lizards wouldn’t win any gold stars at the dentist, Komodos may have a bad rap for oral hygiene. The Komodo dragon’s mouth is no nastier than those of other predators, Fry says. “A lion has a larger bacterial load.”
MRI scans of a Komodo dragon head turned up six venom glands on each side of the lower jaw. All together, these glands can hold 1.2 milliliters of venom per animal. “It’s astounding,” Fry says. “I didn’t expect it to be that intricate of a structure. It was just jaw dropping when we got the first MRI results.”
A technique called mass spectrometry turned up in Komodo venom many proteins known to be in snake venom. In particular, compounds known to widen blood vessels and thin the blood — which induces shock — were present.
Fry and his colleagues injected the venom into rats and confirmed that their blood pressure and aortic tension decreased. After the injection, the rats also became still, an outward sign of shock.
This new paper puts to bed once and for all the issue of how the Komodo dragon kills, Shaw says. The authors “produce some pretty convincing evidence that these are venomous lizards.”
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RE: It’s not their dirty mouths
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by earthguy on May 18, 2009
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Hmmm...that Fry guy sounds familiar. Like maybe I should know him or something. At any rate, I'm sure it's a load of hogwash. Everybody knows that lizards aren't venomous :-)
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RE: It’s not their dirty mouths
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by Buzztail1 on May 18, 2009
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Doug, you are just too funny ;)
This paper actually came out a while ago and some other scientists are still not onboard with his findings.
I, too, agree that BGF provides good scientific study and background to his findings unlike some other folks who just publish things shotgun style hoping something will be accepted.
R/
Karl
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RE: It’s not their dirty mouths
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by tigers9 on May 18, 2009
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DH wrote<<So....not a good starter lizard? >>
Well, I kept non smaller monitors on and off for almost 20 years, am I ready for Komodo?;-)
I think Mandalay Bay in Vegas is AZA and I think they claim to have one here...:)
Z
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RE: It’s not their dirty mouths
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by earthguy on May 18, 2009
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Archie & Carl,
I know BGF. That paper has actually been out for a while. I was just seeing if he was cruising the forums - nothing like a little friendly ciber trash talk :-).
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RE: It’s not their dirty mouths
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by Buzztail1 on May 18, 2009
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I could be wrong, it has been awhile since I read the whole paper, but I believe BGF said that all members of the Varanid clan had some sort of venom but that the effects of the individual venoms would need to be researched to see how they affected humans.
I will have to search my archives and see if I can find it.
R/
Karl
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RE: It’s not their dirty mouths
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by BGF on May 18, 2009
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This is actually a new paper that is a followup to the previous. I FINALLY got my greedy little paws on komodo dragons :)
I'll post a link to the paper later this eve
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RE: It’s not their dirty mouths
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by Cro on May 18, 2009
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It is a great new paper. Now that we have the Monitor lizards sorted out as being venomous, are we next going to do MRI of birds and find out that they two have venom glands, LOL ?
Best Regards
John Z
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