The Truth About Komodo Dragons

The Komodo dragon: surprisingly clean.

The Komodo dragon: surprisingly clean.

Myth-busting science writers, especially when they free a phenomenal animal from the clutch of wrongly bad reputation, are heroic folk to us:

In 1969, an American biologist named Walter Auffenberg moved to the Indonesia island of Komodo to study its most famous resident—the Komodo dragon. This huge lizard—the largest in the world—grows to lengths of 3 metres, and can take down large prey like deer and water buffalo. Auffenberg watched the dragons for a year and eventually published a book on their behaviour in 1981. It won him an award. It also enshrined a myth that took almost three decades to refute, and is still prevalent today.

Auffenberg noticed that when large animals like water buffalo were injured by the dragons, they would soon develop fatal infections. Based on this observation, and no actual evidence, he suggested that the dragons use bacteria as a form of venom. When they bite prey, they flood the wounds with the microbes in their mouths, which debilitate and kill the victim.

This explanation is found in textbooks, wildlife documentaries, zoo placards, and more. It’s also wrong. “It’s an enchanting fairy tale, which has been taken as gospel,” says Bryan Fry from the University of Queensland.

In 2009, Fry discovered the true culprit behind the dragon’s lethal bite, by putting one of them in a medical scanner. The dragon has venom glands, which are loaded with toxins that lower blood pressure, cause massive bleeding, prevent clotting and induce shock. Rather than using bacteria as venom, the dragons use, well, venom as venom. (The full set of experiments is breathtaking in their scope—read about them here.)

Based on a thorough analysis of the dragon’s skull, Fry thinks that they kill with a grip, rip and drip tactic. They bite down with serrated teeth and pull back with powerful neck muscles. The result: huge gaping wounds. The venom then quickens the loss of blood and sends the prey into shock.

That doesn’t discount the possibility that the dragons might also rely on oral microbes. To study these microbes, Fry contacted Ellie Goldstein from the UCLA School of Medicine—an expert on microbes an animal bites. Goldstein has advised people around the world on treating unusual bite wounds, including at least one from a Komodo dragon. “The bacteria-as-venom model seemed to be based on faulty and dated studies,” he says. “There was no really good data on the topic.”

Goldstein tried calling several zoos with captive dragons. “Many would not respond and sometimes actively tried to deter our research for reasons unclear to me,” he says. “The detractors [said] this study had already been done and no new info would result,” adds Kerin Tyrrell, who is part of Goldstein’s team. Fortunately, three zoos in Los Angeles, Honolulu and Houston were more cooperative, and the team managed to swab the mouths of 10 adults and 6 hatchlings.

They found… nothing special. All the microbes they found were common in the skin and guts of their recent meals. There were no virulent species at all, and certainly nothing capable of causing a quick, fatal infection. And the species that were there weren’t particularly abundant. “The levels of bacteria in the mouth are lower than you’d get for a captive mammalian carnivore, such as a lion or Tasmanian devil,” says Fry. “Komodos are actually remarkably clean animals. This is another nail in the coffin to the idea of them using bacteria as a weapon.”

Read the rest of the story here.

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