This Komodo dragon doesn't kill with pure force like a crocodile, but with a lethal duo of toxins and razor-sharp teeth.
SYDNEY: Rather than using a nasty cocktail of bacteria, as previously believed, Komodo dragons use shock-inducing toxins to kill their prey – a finding that may revolutionise medical treatment for bites.
Komodo dragons (Varanus komodoensis) have delicate skulls compared to other carnivorous lizards such as crocodiles, and it has been something of a mystery how they are capable of tackling large prey, sometimes exceeding 100 kg. The findings, published today in the Proceedings of the National Academy of Sciences, now provide a definitive answer.
"[The bite is like a] serrated dagger dipped in poison," explained Bryan Fry, a biologist from the University of Melbourne, Australia and lead researcher behind the study. And he's in a good position to describe it: Fry once had to have emergency surgery to repair a severed artery from just such a bite.
Antibiotics won't fight venom
The three-metre-long Komodo dragon is the world's largest lizard, found on the Indonesian islands of Komodo, Rinca, Gili, Motang and Flores. They feed on a variety of animals, ranging from frogs to adult deer.
Computer modelling has shown that their lightweight skull and jawbones would snap, however, if brute force was the only tactic they used to catch large prey, said Fry.
Since the 1980's scientists have believed Komodo dragons kill their victims by infecting them with highly virulent bacteria. Treatments for dragon bites currently involve a heavy dose of antibiotics.
To Fry, however, this explanation seemed unlikely – Komodo dragons are extremely clean animals that don't harbour masses of killer bacteria, he said. Fry hopes his work on toxins will now change the way human dragon bites are treated.
Venom induces shock
Fry's team analysed a preserved Komodo dragon head using Magnetic Resonance Imaging (MRI). MRI employs strong magnetic fields to construct a picture of the internal structure of the body. Fry's team saw venom glands inside the head – the most complex reptile venom glands ever described, in fact.
To find out how poisonous the venom was, the researchers removed the glands from a captive and terminally ill Komodo dragon. They then determined the venom's 'protein fingerprint' – the protein make-up, which determines its properties.
Komodo Dragon
Frank, it might not take ages to kill the prey if the bacteria that infected the wound were toxic enough. The theory I'd heard is that the deer get sick (and blind!) over the course of a few days, and then when it dies the dragons sniff out the carcass nearby and gather and feed. So it is a "bite and wait" strategy. I have no idea if this is true or how this new venom evidence affects the time for the deer to drop or drop dead.
Is there any documentated cases the whole way from bite to devour with these komodo dragons? That would give some good answers. I have also seen a program in which a local man shows a leg bite he got from a dragon, and how these bites take a long time to heal and even then they don't heal well.
But field studies show the
But field studies show the bitten prey collapsing and being feed upon within HOURS, not days/weeks later. Bacterial infection or sepsis of that magnitude would make the dragon the most toxic and infectious creature on the planet. Yet the bacteria in question is varied (no two dragons have exactly the SAME bacterium present in sampling) and other animals carry similar or worse bacterium and it does not affect their prey (case point: lions). You've already given evidence of known results from less severe wounds (local man with long-healing wounds). Why is it such a leap to SEE the medical exploration (the 2 komodos that were dissected, SHOWING the existance of the glands) plus the MRI scans plus the extraction of said toxins?