Snake venoms are exceptionally varied, depending on prey. Yet even among this diversity, the long-glanded blue coral snake (Calliophis bivirgatus) stands out, having venom more similar to that of scorpions and cone snails than other snakes. Strange as it seems, the first published study of this venom could aid our quest for new painkillers.
Other snakes have evolved venoms particularly suited to fish, reptiles, or mammalian prey, but most work along similar lines, lowering blood pressure and paralyzing the respiratory system. Small prey like rodents take minutes to die, while for humans it can take hours.
For blue coral snakes that would be a problem. They feed on other venomous snakes, which given the chance will bite them back. C. bivirgatus has gone for something different: Their venom “turns on all the nerves of their fast-moving prey... at one time, almost instantly resulting in a frozen state,” said the University of Queensland's Professor Bryan Fry in a statement.
Fry, one of the world's leading venom researchers, has explored the workings of the blue coral snake's venom in the journal Toxins.
Scorpions and cone snails do not face similar risks from their prey, but they do need to prevent them from flying or swimming beyond reach. Naturally, there is a price to pay for such swift-acting killers, and Fry told IFLScience that, drop for drop, the venom other snakes use is more lethal.
“A long-glanded coral snake will need seven times as much venom as a brown snake of the same size,” Fry said. This is why their glands are so long – around a quarter of the snake's body length, while others make do with glands that are just a third the length of the head.