Mega Hammerhead

The hammerhead shark is one of the most recognisable animals on planet Earth. But very few people know that it is also one of the most highly-evolved and specialised predators ever. Dr. Neil Hammerschlag and his team of researchers are setting out on a quest to learn more about this mysterious shark, as well as search for the most elusive of them all - the massive great hammerhead - a shark that can grow up to 20ft in length and can weigh over 1,000 pounds. (National Geographic)