Are Komodo dragons venomous?

by Greg Mayer

Komodo dragons (Varanus komodoensis) are the world’s largest living lizards, reaching 10 feet in length, and are restricted to the islands of Komodo, Rintja, Padar, and Flores in Indonesia. In a soon to be published paper in the Proceedings of the National Academy of Sciences (abstract), Brian Fry of the University of Melbourne and a cast of thousands ( well not quite– there are only 27 coauthors) report evidence that dragons are venomous. This is not as shocking as it sounds. First, the only previously known venomous lizards, the Gila monster (Heloderma suspectum) and Mexican beaded lizard (Heloderma horridum) are members of the family Helodermatidae, which is part of the superfamily Varanoidea, which, as you can tell by the name also includes the Varanidae, to which the Komodo dragon belongs. Fry and colleagues have argued before that venom is more widespread in lizards (and snakes, too) than traditionally thought. Second, dragon bites have long been known to be nasty things, with death often ensuing, but this was thought to be due to sepsis.

Carl Zimmer has an interesting piece on this in the NY Times, in which he notes that Fry et al. have not convinced everyone about dragons being venomous. He talked to my old friend and colleague Kurt Schwenk (and check out UConn’s E&E dept.’s great website) of the University of Connecticut. Kurt was unimpressed by the evidence presented (I can only get the abstract yet, so can’t really comment myself), and had a wonderful way of putting the argument that venom is not necessary to explain why dragon prey die after being bitten:

I guarantee that if you had a 10-foot lizard jump out of the bushes and rip your guts out, you’d be somewhat still and quiet for a bit, at least until you keeled over from shock and blood loss owing to the fact that your intestines were spread out on the ground in front of you.

For further info on dragons, the late Walter Auffenberg‘s classic monograph on dragons, The Behavioral Ecology of the Komodo Monitor (University Press of Florida, Gainesville, 1981) is a must read.


  1. Matthew
    Posted May 24, 2009 at 12:11 am | Permalink

    If my memory serves me right, the Komodo Dragon exhibit at the L.A. Zoo states that the dragons are poisonous. I didn’t realize that this was controversial.

  2. nal
    Posted May 24, 2009 at 1:18 pm | Permalink

    We find that the lightweight skull is relatively poorly adapted to generate high bite forces …

    Don’t they have instruments that can actually measure bite force?

    If they’re claiming venom, they should be able to point to an organ that produces that venom.

  3. Reginald Selkirk
    Posted May 24, 2009 at 6:10 pm | Permalink

    I sent the full text PDF of the article to your UW-P address.

  4. Posted May 24, 2009 at 11:49 pm | Permalink

    Yup.. I know that story.. because I live in Bali Indonesia, near the komodo island.

  5. SeanK
    Posted May 25, 2009 at 10:45 am | Permalink

    Wow, what a conincidence. I was chatting with some friends last night at a BBQ on this very topic. We were trying to figure out if Komodo Dragons had a venomous bite. I’ll have to forward this to them now.

  6. Reginald Selkirk
    Posted May 26, 2009 at 7:02 am | Permalink

    Komodo dragon attacks terrorize Indonesia villages

  7. nicole
    Posted January 31, 2011 at 12:32 pm | Permalink

    ummmm komodo dragons bite force is really low….so i would assume that they were venomous

    • nicole
      Posted January 31, 2011 at 12:41 pm | Permalink

      A Komodo dragon’s mouth is stewing with an estimated 60 different strains of bacteria that infect a prey after a bite. Sepsis sets in within hours and death usually occurs within a day, with the dragon stalking the dying prey closely.

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