  "These extremely large and strong lizards were once not though to possess venom. They were scary predators even before this discovery." ~ Donald Schultz, Host of WILD RECON
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A BITE WITH MORE AND LESS: Lace Monitors Deliver Venom, Not Bacteria
We've all heard the stories: A bite from a
Komodo dragon, the infamous several-meter long lizard found in Indonesia, introduces so much bacteria that the wound becomes horribly infected. If left untreated, the bite leads to septicemia — bacteria in the blood — and a painful death.
Australians tell similar stories about the lace monitor, their country's version of the
Komodo dragon. They claim that the lace monitor, or tree goanna, can inflict serious bites, even though it's about half as big. These bites, they say, can cause severe pain and, in some cases, a raging infection requiring hospitalization.
Beyond Bacteria
As it turns out, none of these stories is true. Or at least the part about the bacteria isn't. Scientists have recently discovered that monitor lizards deposit large amounts of venom toxins, not microscopic germs, as they bite down on their prey. These toxins include a rich brew of chemicals that can interfere with smooth-muscle contraction, dilate blood vessels and inhibit blood clotting. When researchers reported the discovery in a 2006 issue of
Nature, they stunned the scientific community. Until then, the only lizards thought to be venomous were the Gila monster and the bearded lizard. Now it seemed that all monitor lizards, a group of reptiles belonging to the family Varanidae, genus
Varanus, contained venom glands and venom.
Biologists continue to debate the function of venom in monitor lizards. Bryan Fry, the lead author of the
Nature paper, emphatically states on his Web site that varanid venom will not kill a person. "I must stress that the human medical implications [of varanid venom] are trivial," he writes in the online forum of his site,
Venomdoc.com. "Of much more realistic concern are sliced tendons and arteries."
Fry can speak of such injuries from firsthand experience. A lace monitor —
Varanus varius — bit his hand and sliced all the way to the bone with its serrated teeth. While the animal clamped down, it also released a mouthful of venom into the wound. Although the toxins likely exacerbated the bite by thinning the blood and dilating his arteries and veins, they were not, by themselves, life-threatening. The bigger issue was the physical damage to his hand, which required several surgeries to repair.
Venom as Meat Tenderizer
So why would lace monitors have venom? The answer may lie in what the animals eat. Lace monitors are the second-largest carnivores in eastern Australia, taking a back seat only to dingoes. They are opportunistic feeders of a wide range of prey, including carrion. Although they often feed on small birds and mammals, they regularly take down larger animals or large numbers of animals. One researcher reported that a single lace monitor regurgitated four fox cubs, three young rabbits and three large skinks. Another researcher found a lace monitor that had eaten an adult rabbit almost half as large as the lizard. Clearly,
V. varius has an enormous appetite and a stomach to accommodate it. It may also have a great way — venom — to start digesting its food, making it easier to break down and process large amounts of meat.
Komodo dragons also prefer animals larger than themselves. To bring down something as hefty as an adult deer, they rush from a hiding place, take a big bite and retreat, leaving the victim to become weak from blood loss. Then they move in for the kill. Such an attack style suggests that venom with anticoagulant properties, which would make prey animals bleed more profusely, could be quite useful.
Luckily for us, Komodo dragons rarely attack humans. But in eastern Australia, where lace monitors are quite common, even in densely populated areas, bites are possible. The good news: Death from bacteria thriving in the lizard's mouth seems unlikely. The bad news: A serious bite could maim your hand or foot.
Recommended HSW links: Read more about dragons and monsters at HowStuffWorks.com:
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