Killers that also cure.

It's the ultimate Fear Factor nightmare: Chase down one of the world's deadliest snakes, grab it by the head, and squeeze the venom from its fangs. Bryan Fry, a biologist at the University of Melbourne in Australia, does just that with rattlesnakes, king cobras, death adders, sea snakes, and other reptiles most of us would rather avoid. "Working with some of these snakes is the biggest adrenaline rush you could ever do," says Fry. But that rush is not what drives him to handle some 3,000 snakes a year. Fry's goal is to decipher the evolution of snake venoms over the past 60 million years. This research could lead to medical breakthroughs, he says. For the past 35 years, scientists have been turning snake venoms into drugs. The world's deadliest venom comes from Australia's inland taipan: Victims of this nine-foot-long snake collapse within seconds and die quickly. But Fry and his colleagues have found a molecule in its venom that may help treat congestive heart failure. Fry knows that most people don't share his affinity for deadly snakes, but he hopes the creatures will be protected. "If you kill off the snakes," he says, "you could be killing the next wonder drug."