O'Shea's Big Adventure

In a rapidly vanishing habitat on Brazil's Atlantic coast, the largest venomous snake in the Americas is on the verge of extinction.

The tiny South Atlantic outcrop of Queimada Grande is a Lost World, cut off from the rest of nature.

The Patagonian Lancehead lives further south than any snake in the world.

The swamps of America's Deep South hide an ancient mystery - a secretive predator from the age of the dinosaurs.

For Mark O'Shea, the Timber Rattlesnake is Nemesis. After a bite from a captive snake, the reptile hunter and scientist spent nine days in a hospital, close to death.

The Gila Monster and the Beaded Lizard. The world's only venomous lizards. But can they ever be found together?

Baja on the Pacific Coast of Mexico, little known, mysterious - a land of volcanoes and snake infested islands, a land that time forgot.

Mark's quest is to find one of the world's rarest and most beautiful frogs, to save it from the threat of extinction and to study its unique toxin for medical research.

Trinidad, the lush tropical island off the west coast of Venezuela, is home to an incredible range of creatures.

The mouth of the largest river in the world boasts an island the size of Switzerland, an island that's not only huge but extremely unusual.

Mark O'Shea returns to his home from home - the jungles of South America - to capture and photograph reptiles in Guyana's Iwokrama rain forest reserve.

Small villages along the Essequibo River deep in the interior of Guyana are being terrorized by one of the world's biggest crocodilians, the Black Caiman.