As the dry season gets longer each year, the rainy season gets more destructive. In the jungles of Amazon, jaguars and crocks fight over the dwindling prey, but tiny killers like the Cordyceps fungi present true horror.

The highest mountains on Earth are home to snow leopards, golden eagles, mountain goats, barnacle goslings and gelada monkeys. But only the toughest can endure the extreme weather, scarce food and limited oxygen on these peaks. Using new technology to showcase never-before-filmed animal behavior, Hostile Planet provides unique access to one of the most extreme environments on the planet.

Dive beneath the surface of the Earth's vast oceans to uncover a world of extremes, from crushing depths to stormy coasts to crowded reefs. Oceans are dynamic environments where animals must adapt to life of constant change. Discover how seals fend off sharks, how turtles risk their lives to create their next generation and how ingenious orca fight to survive in the face of competition.

The planet's hottest habitats - our deserts - are getting even hotter, drier and bigger, yet a host of remarkable animals still survive in the harshest conditions, including cunning hyenas, pint-sized meerkats and sand-dwelling spiders. Follow their lives through a single day in the desert to appreciate how they deal with the sun's formidable power as it grows stronger with every passing minute.

Step inside the most frigid habitats on Earth - the poles. Here, the planet's ultimate survivalists include whale-hunting polar bears, leopard-seal-dodging penguins and a pack of Arctic wolves that can bring down a pair of musk oxen. Evolution has helped polar species combat the intense hostility of their habitats, but their world is changing rapidly and their resilience will be tested.

Grasslands are home to the biggest stars of the animal kingdom, but top billing doesn't make life here any easier. These are some of the most volatile environments, where animals must endure an ever-shifting journey through freeze, fire, flood and drought. Life is harder than ever for the wildlife featured in this episode, from harsh weather and mating battles to the predator-and-prey dance.