For the longest time, people believed that the world’s largest lizard, the Komodo dragon, killed its prey with a dirty mouth. Strands of rotting flesh trapped in its teeth harbour thriving colonies of bacteria and when the dragon bites an animal, these microbes flood into the wound and eventually cause blood poisoning.
But that theory was contested in 2005 when Bryan Fry from the University of Melbourne discovered that a close relative, the lace monitor, has venom glands in its mouth. The discovery made Fry suspect that Komodo dragons also poison their prey and he has just confirmed that in a whirlwind of a paper, which details the dragon’s “sophisticated combined-arsenal killing apparatus”.
By putting a virtual dragon skull through a digital crash-test, Fry showed that its bite is relatively weak for a predator of its size – instead it’s adapted to resist strong pulling forces. This is a hunter built to inflict massive wounds through a “grip and rip” style that involves biting lightly but tearing ferociously.
The wounds provide a large open area for the dragon to inject its venom and Fry unquestionably showed that the dragons poison their prey. By placing the head of a terminally ill dragon in an MRI scanner, he managed to isolate the venom glands, which turn out to be more structurally complex than those of any other snake or lizard. He even managed to analyse a sample of venom, which is loaded with toxins that prevent blood from clotting and induce shock.
And as the icing on the cake, Fry concluded that Varanus prisca, a extinct close relative of the Komodo dragon probably also had venom glands. Also known as Megalania, V.prisca was three times the size of the Komodo dragon, making it (to our knowledge) the largest venomous animal to have ever lived.