This episode focuses on the Jurassic period, a time when the first giant killers stalked the Earth and lurked in the seas; a time when the slightest advantage meant the difference between life and death. In North America the iconic allosaurus, an ambush hunter with a lethal bite, dominated. Not even the heavily-armoured stegosaurus was safe from this killer, and incredible evidence reveals a glimpse of a vicious battle between these two giants. Life in Jurassic oceans was no easier; in 2008, a fossil was dug out of a frozen island high in the Arctic. It was a colossal marine reptile, twice as big as most ocean predators, at 15 metres long and weighing about 45 tonnes. This was Predator X. Its skull alone was nearly twice the size of a tyrannosaurus rex's, and its bite force unmatched by anything in the Jurassic seas. The balance of power between predator and prey is a fine one, as prey continually evolves different ways to avoid predators. But for the most successful and enduring predators, the battle to survive has always been tipped in their favour.
In southern Israel, two vastly different worlds live side-by-side. A tropical sea and ancient coral reef teem with aquatic life alongside a harsh desert landscape filled with hardy reptiles and alien acacia trees. Venture into a part of Israel that few people imagine exists.
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.
From penguins whose salt-removing eye glands shield them from the harsh ocean to caterpillars whose fake facial markings are meant to mimic a snake's, animals have evolved in amazing ways to see and be seen. Meet these creatures and see how they use eyes and illusions to their advantage.
Take flight across Botswana's sprawling Kalahari Desert, through the Okavango Delta, and deep into its dynamic history. During the journey, Botswana's history of ancient civilizations, notorious slave traders, and enormous wealth are brought to life.
The American Dipper can plunge its head into freezing Arctic water up to 60 times a minute. In the summer, ferocious mosquitoes can draw up to a pint of blood a day from caribou. Take a fascinating look into the Arctic seasons and the impact that rising sea levels have on local wildlife, and, ultimately, our own world.