Lack of evidence for komodo dragons and weaponised bacteria

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venomdoc
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Lack of evidence for komodo dragons and weaponised bacteria

Post by venomdoc »

After much delay by one of the world's slowest journals, our paper on the relative presence bacteria in komodo dragon mouths is finally out. This is another nail in the coffin to the idea of komodo's using bacteria as a weapon. If this was the case, then they would be expect to have very high bacteria loads even in captivity, facilitating the blooming of anything that comes by. Instead, they have the normal loads of transient bacteria expected of any other animal. Nothing special at all going on in there!! Our next step is to culture the festering stagnant watering holes on the islands to show the true source of any infection to the introduced water buffalo from after injury.

http://www.venomdoc.com/downloads/2013_ ... cteria.pdf

The anguimorph lizards have a combined arsenal system employing teeth and venom. Helodermatids are one extreme, with the deeply grooved gracile teeth restricted to a venom delivering role. In contrast, komodos have the large serrated teeth as the primary weapon, using a grip-and-rip strategy to inflict deep parallel wounds. Mechanical damage that in some cases results in very rapid death from blood loss (eg slicing the femoral artery). The role of the venom is to exaggerate the blood loss and shock inducing mechanical damage caused by the bite. We have identified two main actions common to all anguimorph venoms: anticoagulation and hypotension. Enough loss of blood would lead to a drop in blood pressure sufficient to induce shock or unconsciousness. So anticoagulant toxins facilitate a steady march in this direction. Similarly,hypotensive toxins accelerate the unconscious endpoint.

Komodos evolved not in Indonesia but in Australia, and were not the biggest to have roamed, at least two larger varanids existed to predate on megafauna. The second largest radiated to Timor while komodo radiated to Flores and nearby islands. The modern day situation is that the komodos have three mammalian potential prey choices. All of which are feral. The introduced pigs and deer are within the natural prey size (40-50 kg) while the buffalo are dramatically larger than would have been a reasonable size for komodos to kill and also occupy an ecology unlike anything in Australia.

These collective differences are starkly reflected in attack success. Attacks on pigs and deer are extremely successful. About three quarters bleed out within the first thirty minutes and another approximately fifteen percent succumb within three or four hours. Repeated attacks by the same or other komodos is not uncommon. In dramatic contrast is the outcome of attacks on water buffalo. Which invariably get away, with deep wounds to the legs. Upon which they go and stand in feces filled watering holes. Creating a perfect scenario for dramatic infections. Not from the dragons mouth, but rather having an environmental source. Deep wounds in feces laden water is a perfect scenario for the flourishing of bacteria, particularly the nasty anaerobic types. Thus, the previous sampling of komodo mouths that purported to show them harbouring pathogenic bacteria neglected to sample the real source of any infection to the water buffalo: the faeces filled waiting hole the dragons recently drank from. It has been a man made artificial scenario all along that has nothing to do with the evolution of the predatory ecology of komodos.

Having gotten septicaemia in Flores from deep lacerations resulting from a boating mishap in Flores harbour (water that is pretty disgusting) I can attest to how quickly such environmental sources can produce life threatening infections. As a consequence of the Flores doctor doing a shockingly inept job of cleaning up the wounds before stitching them up, I ended up delerious and near unconscious in the Bali International SOS clinic 36 hours getting emergency IV antibiotics.

There is nothing special about komodos. They are simply the largest extant species of a clade that had two extinct larger species and has two extant species (V. varius and V. salvadorii), all of which share the unique large,blade like serrated teeth. None of which have ever had the slightest whiff of using bacteria as a weapon.

:)
Tamara D. McConnell
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Joined: June 7th, 2010, 11:42 am

Re: Lack of evidence for komodo dragons and weaponised bacte

Post by Tamara D. McConnell »

This is really interesting. Thanks!
ADCIII
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Joined: August 26th, 2010, 10:56 am

Re: Lack of evidence for komodo dragons and weaponised bacte

Post by ADCIII »

Thank you very much. I have heard this (and believed it) for over 50 years!!! It is refreshing to see an unbelievable story can be explained by simply analizing and investigating the facts. Art
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Biker Dave
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Re: Lack of evidence for komodo dragons and weaponised bacte

Post by Biker Dave »

This will make some good lunch time reading! Thanks Doc!

By the way, when will you be returning to Arizona to herp?

Dave
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