The grasslands of our planet are some of the most challenging habitats for playing the Mating Game. They are an open stage where potential partners and jealous rivals can witness your every move… and every failure.
Going down into these narrow flooded passageways is not for the faint-hearted but, with only an estimated one percent of the caves explored, it is an opportunity for the team to write themselves into cave diving history, by pushing further in than anyone has before. This is a challenge that tests even the most accomplished cave divers. Steve must face the terrors of being lost in an underwater silt cloud in a cave. But there is a bigger issue at stake. All life in the Yucatan depends on the fresh water in this network of caves, but it's being contaminated by human development. With every metre the team maps, it adds to the knowledge of the system, which, in turns, helps protect it for future generations.
What is it that makes things alive? What if we made robots that could sustain themselves? What if they could mine metals or recycle old robots, reprogram and remake themselves? There's nothing there we would traditional call alive, but they would have at least have the essence of this perpetual rube Goldberg machine.
The first programme shows how sharks are the ocean's great predators, living in every ocean and hunting in every way. Blacktip sharks hunt in huge packs and herd fish into baitballs, tasselled wobbegongs are ambush hunters, Greenland sharks live under the arctic ice, and whitetip reef sharks are the masters of hunting at night. The finale shows the great white in its hunt for fur seals off the coast of South Africa.