Here Be Dragons: The Mythic Bite of the Komodo

By Christie Wilcox | June 25, 2013 8:00 am

Here Be Dragons: first written on the Hunt-Lenox Globe c. 1510 as the latin phrase HC SVNT DRACONES.

To a mediaeval mapmaker, the world was a vast and scary place. Explorers that braved the seemingly endless oceans in search of new worlds often didn’t return, and those that did carried with them nightmarish tales of monsters and serpents. It was the mapmaker’s task to warn future travelers of the dangers that awaited them in far-off lands. Based on their drawings, I cannot even begin to imagine the beasts that haunted these cartographer’s dreams. Their creative expressions of fear were eventually distilled into a single, ominous phrase: here be dragons.

Lands that still deserve this cartographer’s omen, however, can be counted on one hand. They are the Indonesian islands of Rinca, Gili Motang, Flores, and Komodo — the only places in the world where dragons still roam.

I am, of course, referring to the infamous Komodo dragon (Varanus komodoensis). This gigantic species of monitor lizard grows up to ten feet long and can weigh in the hundreds of pounds. It’s no wonder, then, that for centuries Komodos have been feared by many, with tales of their deadly bite echoing through local cultures. It’s even thought the monstrous lizards may have inspired the mythical beasts that share their name. Their villainous reputation only grew when these fearsome predators were discovered by Europeans in the early twentieth century. But of all the terrible tales told about these dragons, none has been so persistent and pervasive than that of their bite. The mouths of Komodos are said to be laden with deadly bacteria from the decaying corpses they feed on, microbes so disgustingly virulent that the smallest bite lethally infects prey. As the story goes, Komodos have turned oral bacteria into a venom.

It’s a truly fascinating way  for an animal to feed — well, truly fascinating in that it’s not true at all.

While man’s best friends were once falsely accused of perfect oral hygiene, the poor dragons have been dubbed dental delinquents for the better part of the past half century. It appears that the filthy rumor started with early Komodo biologists in the late 1970s to early 1980s. Esteemed herpetologist Walter Auffenberg spent an entire year on the island of Komodo, watching and tagging the lizards to learn about their ecology. In his book on the subject, he noted that dragons fearlessly tackle animals like water buffalo that can be ten times their size. He also noticed that, often, they would fail to kill these massive prey when they attacked. But that didn’t mean the dragons went hungry — within days of that first bite, many of the bitten buffalo succumbed to sepsis, either dying from bacterial infection or so weakened by it that they were no match for the large lizards. This led Auffenberg to the idea that “induction of wound sepsis and bacteremia through the bite of the Komodo dragon may be a mechanism for prey debilitation and mortality.” Further research seemed to support this hypothesis, as pathogenic bacteria were isolated from Komodo saliva.

A squeaky-clean Komodo dragon

But the idea that Komodo mouths were these teeming pits of virulent bacteria never sat well with Bryan Fry. “Komodo dragons are actually very clean animals,” he explains. Fry, venom researcher and Associate Professor at the University of Queensland, has worked with all kinds of animals, from spiders to snakes. The notorious Komodos are no dirtier than any other species he’s studied, he says. “After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth… Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria.”

Komodos, like other monitor lizards, are close relatives of snakes. In 2005, Fry and his colleagues published a paper in Nature showing that all of the species in this clade of reptiles share the same venom genes, suggesting that the early ancestor of all monitor lizards and snakes was venomous. Still, many were reluctant to give up on the long-held belief of a bacterial Komodo bite. Even in 2009 when Fry and his team captured images of Komodo venom glands using MRI technology and showed that the toxins they produced could cause severe drops in blood pressure, others called his findings “meaningless, irrelevant, incorrect or falsely misleading.”

This month, the dirty myth of the Komodo’s bite is finally laid to rest, the last nail in the coffin again coming from Bryan Fry. In a new paper, Fry and his colleagues show that the bacteria present in Komodo mouths are surprisingly ordinary, similar to what scientists find in any carnivore. Most importantly, the oral flora doesn’t posses the pathogenicity required to kill. As for the previous research that found virulent bacteria, the authors note that those species were identified “without the advantage of molecular methods.” Of the 54 that previous research claimed to be “potentially pathogenic,” 33 are actually common microbes and “unlikely to be the cause of rapid fatal infection when present in a wound.” The one species hailed as the probable cause of sepsis in the original paper wasn’t found in any of the dragons this time around, and, the authors note, was only found in 5% of the dragons studied in the first place. Taken together, the evidence suggests that the bacterial bite hypothesis doesn’t hold up. Rather than sepsis waiting to happen, the bacterial community in Komodo spit “is reflective of the skin and gut flora of their recent meals as well as environmental flora.”

What about the water buffalo that die days after being bitten? The explanation, Fry says, has been right under our noses.

When Komodo dragons attack pigs or deer, they kill quickly. Three quarters of these smaller prey bleed out within 30 minutes from massive wounds inflicted by the dragon’s serrated teeth and anti-clotting venom toxins. Another 15 percent die within hours, likely succumbing to muscle weakness and low blood pressure caused by other venom components. Water buffalo, on the other hand, usually get away with deep but otherwise non-mortal wounds to their legs.

The reason the buffaloes get away is that Komodos aren’t naturally equipped to take down such large beasts. As relative newcomers in the Komodo’s realm, water buffalo weren’t originally a part of the dragons’ diet. The lizards once preyed upon much smaller targets, the young of megafauna long extinct. Pigs and deer aren’t original menu items either, but as Fry explains, “the introduced pigs and deer are within the natural prey size,” which is why the dragons are so good at killing them. “The buffalo are dramatically larger than would have been a reasonable size for komodos to kill.” It never made evolutionary sense that Komodos had adapted such a targeted way to take down large prey within such a brief period of contact. Now, the evidence suggests they didn’t — they just got lucky that the buffalo’s instincts are all wrong.

Water buffalo get their name from their affinity for — Surprise! — water. When injured or scared, they flee to the relative safety of the deep. These buffalo aren’t native to the Indonesian islands; they evolved where large, fresh marshes are commonplace. But on the dragon isles, clean water pools are in short supply. The buffalo instead wallow in stagnant, warm water filled with their own feces. These sewage filled holes, says Fry, are breeding cesspits of pathogenic bacteria. “It is when the water buffalo go stand in the toxic water with gaping wounds that they get infected,” he says. “It really has been that simple all along.”  As for previous research that found nasty bacteria in Komodo saliva, Fry has an equally straightforward response: the few dragons that had these species in their mouths had recently drank the same disgusting water.

Fry is all too familiar with just how nasty some of these bacteria can be. “Having gotten septicaemia in Flores from deep lacerations resulting from a boating mishap,” he said in a Facebook post, “I can attest to how quickly such environmental sources can produce life threatening infections.”

Komodo dragons — lizards the size of men with large, serrated teeth and a venomous bite — certainly are the stuff of legends, but their septic bite is nothing more than a myth. Scientists don’t always get things right the first time around, and sometimes, even the most careful observations can miss what’s really going on. In this case, the strange interaction between a novel meal option and a notorious beast confused early investigators. “If water buffalo had never been introduced onto the islands, then this enchanting fairy tale never would have come into existence,” says Fry.

The truth, of course, is of little comfort to anyone planning to visit the islands where dragons roam. Don’t worry, you won’t die of sepsis from a Komodo bite. You’ll just die when the gigantic lizard with inch-long serrated teeth dripping with hemorrhagic venom tears your flesh to shreds.

 

Citation: Goldstein E.J.C., Tyrrell K.L., Citron D.M., Cox C.R., Recchio I.M., Okimoto B., Bryja J. & Fry B.G. (2013). ANAEROBIC AND AEROBIC BACTERIOLOGY OF THE SALIVA AND GINGIVA FROM 16 CAPTIVE KOMODO DRAGONS (VARANUS KOMODOENSIS): NEW IMPLICATIONS FOR THE “BACTERIA AS VENOM” MODEL, Journal of Zoo and Wildlife Medicine, 44 (2) 262-272. DOI:  (PDF)

Image credits: Lenox Globe from Wikipedia, Komodo Dragon taken by Christie Wilcox at the Honolulu Zoo

CATEGORIZED UNDER: Evolution, select, Top Posts
  • Sandgroper

    Very nice piece, Christie. Interestingly, it has subsequently been found that Perentie are also somewhat venomous, something that was hitherto never suspected. As a kid I kept hearing folk tales about how “goanna bites won’t heal”. I suspect now we know why – hemorrhagic venom.

  • Sandgroper

    Sorry, serial posting – it’s a function of brain deterioration.

    Now to really give ourselves nightmares, we can imagine that Varanus priscus (‘megalania’) was similarly venomous, and twice as long (and possibly 3 times as heavy) as a Komodo Dragon. I have nothing but admiration for the first people to enter Australia, with nothing to defend themselves other than fire and hardwood spears.

  • ThreeRing

    One of my favorite things about science is that when new information conflicts with older knowledge, there’s a battle for supremacy, and it happens not in opinions, but in the quality of the information and how well the new conclusions are supported by ALL of the past measurements. This new conclusion, if correct, satisfactorily explains the morbidity of bitten cattle and smaller prey and allows the new data (the samples of bacteria in the mouth of the komodo dragon) to coexist without conflict.

    • TeamRed_vs_TeamBlue

      This science stuff makes Baby Jesus sad.

      • Steve Matsukawa

        Oh shut up.

      • Allan Richardson

        No, it only has people with a “baby” understanding of Jesus sad, because they refuse to use their brains for anything other than memorizing Bible verses out of context (it is MUCH better to study them IN context, even if you have to look them up occasionally) to “prove” old and disproven ideologies.

        He took away your SINS, not your BRAINS.

        • TeamRed_vs_TeamBlue

          That’s great. Got any evidence?

    • Janice S. Roberts

      like Josephine explained I am stunned that any body can make $9902 in 4 weeks on the computer. have you seen this webpage w­w­w.K­E­P­2.c­o­m

  • Heatwolves

    weird..was just watching “Life” last night and they said the Komodo’s venom kills its prey slowly over weeks. in this episode, a gang of Komodos stalked a Water Buffalo after biting it and just waited for it to die, then feasted.

    • http://blogs.discovermagazine.com Eric Brinkman

      There are several interesting aspects to this story: the most obvious one that “science” could have got it so wrong for so long.

      But biologically, what I’m interested, which no one seems to have noticed, is that these lizards are smart enough to stalk something for several days and wait for it to die. I’ve never heard of a behavior like that from a lizard. Are they smart enough to know the buffalo will die? Did they evolve that behavior in such a short time? Or is it just some kind of predetermined instinct to follow prey?

  • nimblebooks

    Thanks for ruining a perfectly good myth. So the truth is that water buffalo are exttremely stupid!

    • Allan Richardson

      Not stupid (no more than other bovines), just maladapted to their new (a few centuries) environment. They do just fine since they were imported into Italy though. LOVE that Mozzarella!

  • Rogervzv

    These are magnificent animals which I hope we will protect and preserve.
    Scientists get a lot of things wrong. Just look at the Global Warming farce and hoax.

    • Timmay11

      Global warming hoax? Have any citations to support your outlandish claim?

      • VirginiaConservative

        Do you have any to support your claim?

    • BPollutin

      farce and hoax? If stupidity was an infection…you’d be dead!

  • Abraham

    Love it! Sometimes the answer is indeed right before us as we easily miss it while trying to comprehend a more elaborate possibility.

  • Adrian Morgan

    I think I first learned about the Komodo and its bacteria-infested bite
    from Douglas Adams in Last Chance To See. I wish we
    could know what he would have said had he lived long enough to discover
    that it’s not true. One more in my long list of wishes that could be
    granted by the invention of time travel.

  • Lance Gritton

    This paper did nothing of the sort; this is strong hope imposed on weak data; all the oral swabs were from Varanids in zoos. He did not swab wild komodos. Zoos are very clean compared with Indonesian islands. The jury is still out on this IMHO (note, I couldn’t read the whole paper due to pay wall but this is from the abstract).

  • Bryan Grieg Fry

    The next step in our research is to culture the watering holes. We will be sampling widely, not only on Rinca and Komodo islands but also in the native range of the water buffalo as well as in northern Australia where they have also been introduced. The below images illustrate just how
    putrid the water is and the sort of non-lethal wounds that the water buffalo are getting, that facilitates the entry of the bacteria from the truly disgusting water,
    http://www.venomdoc.com/downloads/water_buffalo_I.jpg
    http://www.venomdoc.com/downloads/water_buffalo_II.jpg

  • Bryan Grieg Fry
  • UnapologeticConservative

    People who believe scientist can give the final word on anything are idiots. The history of science is the history of getting things completely wrong. Furthermore, in today’s hyper-politicized and agenda driven society, scientist have become mercenary hit-men, providing whatever rationale is needed to support a political viewpoint, whether the assertion is that homosexuality is normal or that mankind is driving up the Earth’s temperature. Witch-doctors shaking their rattles at the sky, then taking credit when it rains … carefully ignoring all the times the rain didn’t come. Faith in science and scientists is like believing in a flying spaghetti monster.

    • Bryan Grieg Fry

      Unlike religious spin-doctors, scientists never claim to have the final word on anything. Rather we groove on an endless quest for knowledge about the extremely cool biodiversity that has evolved over the eons.

    • Joshua Naterman

      And yet here you are, using the product of unreliable science. Interesting.

      Here’s an idea: Scientists are people, and as such there is a wide range of types of scientists. Some are, as you say, no more credible than the witch-doctor shaking that rattle, at best… they will make the data fit their desired conclusion. They are bad scientists, just as the witch doctor is a bad rainmaker. Other scientists are truth seekers, and don’t care about what the conclusion is, only that it lines up with available evidence, and are completely willing to change what they say as they start getting more information. The best scientists avoid jumping to conclusions and will specifically outline for the readers exactly where there is uncertainty, and what (if any) ideas THEY have for bringing more facts to light in the future.

      Scientists are just people… You can’t rely on any person just because they are in a profession, you have to do a little critical thinking and investigation on your own. If you want to know who to believe, you better learn how to think critically and read fine print.

      If someone just believes the first voice they hear, without doing any kind of quality control checks, then they are going to have a lot of problems in life.

      Bad doctors don’t mean medicine is worthless. Bad priests don’t mean religion is worthless. Bad scientists don’t mean science is worthless.

      • Allan Richardson

        Excellent reasoning. Of course, since most of us do not have the laboratory equipment, training or money to do every experiment for ourselves, we have to rely to some extent on the “scientific establishment” for their results. Science actually operates on a ping-pong between theory and data; data suggests a theory, and additional work generates more data to either support that theory or overthrow it. However, once a theory is generally accepted because it explained all the originally known facts, it takes repeated, careful experiments to overthrow because scientists also know that errors in technique or limitations of available equipment can change results.

        Newton’s theories of motion, assuming an unmoving universal space and time, were not overthrown until the M-M experiment found an exception, after which Einstein took over. But they are still good enough approximations to fire bullets or rockets, fly planes in Earth’s atmosphere, and compute the effects of crashes. Although SOME scientists (Nazis) rejected Einstein’s “Jewish science” in favor of “Aryan science” (which, ironically, kept them from building their bomb) because of ideology, just as some Americans reject climate change because of ideology, MOST scientists were skeptical, but willing to do further testing (one early confirming experiment for General Relativity was the 1920’s expedition to film a solar eclipse, showing that light from stars was bent as it passed by the sun).

        I love the fact that further study of Komodo dragons took place, as well as the fact that I do not have to risk my life and spend money I cannot pay back to do those experiments myself!

    • Allan Richardson

      Michelson and Morley got the Nobel Prize in physics for doing an experiment that FAILED. They were trying (with very expensive equipment, including putting their optics on a large round stone “table” floating on mercury in a pool cut into an even larger stone table) to find Earth’s actual speed through the “ether” which was assumed to carry light waves. Their experiment showed that there was NO difference in the apparent speed of light when the path was with, against, or across the “ether stream.” This opened the way for Einstein’s Special Theory of Relativity to explain the “failure” with a lot of equations, of which the famous E=mc**2 was a small part.

  • Sabastian78
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About Christie Wilcox

Dr. Christie Wilcox is a science writer and postdoctoral scholar at the University of Hawaii. She is renowned in the science blogosphere for her delicate balance of contemporary science and scientific perspective seasoned with just the right amount of wit. Her award-winning posts have landed on the pages of major media outlets including The New York Times and Scientific American. To learn more about her life and work, check out her webpage or follow her on Twitter, Google+, or Facebook.

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