Venom is Komodo dragon's lethal weapon
http://www.timesonline.co.uk/tol/news/uk/science/article6316672.ece
The Komodo dragon is not just the largest living lizard, but one of the most venomous creatures on earth, scientists have found.
The huge, carnivorous lizards, which can tear their prey apart, kill their victims with venom rather than bacteria-laden bites, as scientists have always believed.
The dragons, which grow to a length of about 10 feet (three metres) and weigh around 130lb (59kg) are vicious predators, preying on animals as large as deer.
Commonly, they attack their prey by repeatedly biting and tearing, then wait as it dies a lingering death.
Because they also feed on carrion, scientists have always believed that their mouths must be teeming with bacteria and that those germs infected their victims, slowly killing them.
But magnetic resonance imaging scans have shown that Komodos have complex glands in their mouths that produce venom similar to that of many snakes.
The lizard's sharp, serrated teeth open up wounds into which the venom flows, from the gland that runs along the jawline.
As the wound bleeds the venom acts as an anti-coagulant, increasing the blood flow and reducing blood pressure, sending the victim into shock. Because the victim's blood cannot clot, it bleeds to death.
The venom make the animals formidable killers, even though they have a much weaker bite than a crocodile.
"The teeth and the venom work in perfect harmony," said Dr Bryan Fry, head of the international team whose research on the lizard's formidable killing powers is published in Proceedings of the National Academy of Sciences.
"It works as well as a poisoned dagger," the venom expert from Melbourne University told The Times. "It is an amazing killing machine."
Although they commonly attack large animals, Komodos rarely attack humans. However two years ago an eight-year-old Indonesian boy was attacked and killed in a park on Komodo island. Earlier this year a Komodo stalked a poacher for several days before killing and eating him.
Until now, despite the fact that the dragon's venom gland visibly runs along its jawline, scientists had not realised it was even poisonous.
"That's because no one bothered to look," sid Dr Fry, who noted the gland during his work with captive Komodos at Singapore zoo.
He also noted that, rather than having a mouthful of deadly bacteria from rotting carrion stuck in their teeth, their dental hygiene was impeccable. "Their gums are very pink," he said. "They are very clean animals."
The endangered Komodo, which is found only the Indonesia islands of Komodo, Flores and Rinca, inherits its size and venomous punch from its extinct ancestor, the megalania, a giant goanna found in Australia 400,000 years ago.
Research carried out by Dr Fry's colleague, the biomechanist Stephen Wroe, found that the megalania, which grew to 23ft was the most venomous creature that ever lived.
It also revealed that the two lizards had similar anatomies with lightweight but sophisticated cranial and dental structure that allowed them to kill large prey despite a relatively weak bite.
The discovery adds to growing evidence that many lizards may possess snake-like venom.
Until recently only two poisonous lizards were thought to exist, the Gila monster and Mexican beaded lizard.
Both live in the southern US and Mexico and have a venomous bite that is dangerous but usually not lethal to humans.
http://www.timesonline.co.uk/tol/news/uk/science/article6316672.ece
The Komodo dragon is not just the largest living lizard, but one of the most venomous creatures on earth, scientists have found.
The huge, carnivorous lizards, which can tear their prey apart, kill their victims with venom rather than bacteria-laden bites, as scientists have always believed.
The dragons, which grow to a length of about 10 feet (three metres) and weigh around 130lb (59kg) are vicious predators, preying on animals as large as deer.
Commonly, they attack their prey by repeatedly biting and tearing, then wait as it dies a lingering death.
Because they also feed on carrion, scientists have always believed that their mouths must be teeming with bacteria and that those germs infected their victims, slowly killing them.
But magnetic resonance imaging scans have shown that Komodos have complex glands in their mouths that produce venom similar to that of many snakes.
The lizard's sharp, serrated teeth open up wounds into which the venom flows, from the gland that runs along the jawline.
As the wound bleeds the venom acts as an anti-coagulant, increasing the blood flow and reducing blood pressure, sending the victim into shock. Because the victim's blood cannot clot, it bleeds to death.
The venom make the animals formidable killers, even though they have a much weaker bite than a crocodile.
"The teeth and the venom work in perfect harmony," said Dr Bryan Fry, head of the international team whose research on the lizard's formidable killing powers is published in Proceedings of the National Academy of Sciences.
"It works as well as a poisoned dagger," the venom expert from Melbourne University told The Times. "It is an amazing killing machine."
Although they commonly attack large animals, Komodos rarely attack humans. However two years ago an eight-year-old Indonesian boy was attacked and killed in a park on Komodo island. Earlier this year a Komodo stalked a poacher for several days before killing and eating him.
Until now, despite the fact that the dragon's venom gland visibly runs along its jawline, scientists had not realised it was even poisonous.
"That's because no one bothered to look," sid Dr Fry, who noted the gland during his work with captive Komodos at Singapore zoo.
He also noted that, rather than having a mouthful of deadly bacteria from rotting carrion stuck in their teeth, their dental hygiene was impeccable. "Their gums are very pink," he said. "They are very clean animals."
The endangered Komodo, which is found only the Indonesia islands of Komodo, Flores and Rinca, inherits its size and venomous punch from its extinct ancestor, the megalania, a giant goanna found in Australia 400,000 years ago.
Research carried out by Dr Fry's colleague, the biomechanist Stephen Wroe, found that the megalania, which grew to 23ft was the most venomous creature that ever lived.
It also revealed that the two lizards had similar anatomies with lightweight but sophisticated cranial and dental structure that allowed them to kill large prey despite a relatively weak bite.
The discovery adds to growing evidence that many lizards may possess snake-like venom.
Until recently only two poisonous lizards were thought to exist, the Gila monster and Mexican beaded lizard.
Both live in the southern US and Mexico and have a venomous bite that is dangerous but usually not lethal to humans.
