No other group of fish has such a diversity of horrors, or has spread so successfully around the world. In this River Monsters Special, Jeremy Wade re-lives his most intense encounters as he asks: Why are Catfish so often at the top of the suspect list?

No other group of fish has such a diversity of horrors, or has spread so successfully around the world. In this River Monsters Special, Jeremy Wade re-lives his most intense encounters as he asks: Why are Catfish so often at the top of the suspect list?

The team build a 15-foot high wasps' nest in the middle of New York, complete with human-scale cells and 'larvae' (actually white balloons).

The team build a 15-foot high wasps' nest in the middle of New York, complete with human-scale cells and 'larvae' (actually white balloons).

Is there a snakelike fish in New Zealand that could devour you? Or a fishlike being in Japan that stalks children? In this River Monsters Special, Jeremy Wade untangles fact from fiction as he re-lives the beasts that lie behind lethal legends.

Jeremy recalls close encounters with dangerous marine animals, including wolffish and whaler sharks.

Is there a snakelike fish in New Zealand that could devour you? Or a fishlike being in Japan that stalks children? In this River Monsters Special, Jeremy Wade untangles fact from fiction as he re-lives the beasts that lie behind lethal legends.

Jeremy recalls close encounters with dangerous marine animals, including wolffish and whaler sharks.

Patrick Stewart investigates the defensive tricks of the camouflaged octopus, electric eel, and regenerating salamander.

Jeremy Wade returns to Australia's croc-infested Fitzroy River for one of his toughest quests yet � to catch one of the world's rarest fish. This shark is so elusive it was only discovered ten years ago, and so rare only a handful of people have ever seen it. Almost nothing is known about this endangered beast. Could it be a man-eater? The expedition turns Wade's knowledge of freshwater killers upside down as these animals seem to break all the rules.

Christmas proves rewarding to many at the agency; Harry does a good turn for a friend.

Jeremy Wade returns to Australia's croc-infested Fitzroy River for one of his toughest quests yet � to catch one of the world's rarest fish. This shark is so elusive it was only discovered ten years ago, and so rare only a handful of people have ever seen it. Almost nothing is known about this endangered beast. Could it be a man-eater? The expedition turns Wade's knowledge of freshwater killers upside down as these animals seem to break all the rules.

Investigating the role animals play in religion, Henry sees a desert ritual in which spiritual seekers illegally smoke the poisonous skin of a Sonoran toad. And, in the snake-handling churches of Appalachia, he finds even Christianity has room for a surprising role for dangerous animals.

Anyone who has ever worked in a controlled environment like a zoo with venomous snakes knows that the possibility of a venomous snake bite is serious business. Protocol including alarms and lock down procedures are common place. The right snake, the wrong timing and fangs meeting flesh merits an emergency situation and the entire facility jumps into action. Yet, there are individuals who keep deadly snakes in situations without any backup. Are they thrill-seekers or just naïve? Henry Rollins meets people obsessed with dangerous snakes in �Fatal Obsession� the first episode of Animal Underworld and looks into this very question. Crazy or not, if someone is bitten by a deadly snake with no one for miles around, what really happens? It all depends on the venom.