Poison jewels: the dart frogs

When stressed, poison dart frogs release several different poisons through their skin. If the bright warning colours don't put off predators, the poison enters the attacker's bloodstream rapidly through the mouth. Paralysis and death follow. The frogs eat a diet rich in poisonous ants, which in turn makes them poisonous.

Indigenous people in Colombia tip their hunting darts with the skin extract. Small prey, such as monkeys, are killed instantly and fall to the forest floor. However, once eaten, the poison is much less toxic, making the hunted animals safe for humans to eat.

Recently researchers have developed a painkiller known as 'ABT-594' using the frogs' poison, which has been found to be 200 times as powerful as morphine, but without any side effects and without causing addiction.The toxins from Dendrobates auratus are being studied for their potential use in treating heart attacks.