The contests between predators and prey are the most dramatic events in nature. Taking an intimate and detailed look at the remarkable strategies employed by hunters to catch their prey and the hunted to escape. Sir David Attenborough narrates. "The Hardest Challenge" reveals the extraordinary range of techniques predators use to catch their prey - from a leopard using all its powers of stealth to stalk impala in broad daylight to wild dogs, whose tactic is to wear down their prey over long distances; from Nile crocodiles, the planet's most patient predators, to killer whales who use teamwork and intelligence to take on humpback whales. But even with these finely tuned strategies, the outcome is far from certain. Surprisingly, most predators fail most of the time.

It is high summer in the Polar Regions, and the sun never sets. Vast hordes of summer visitors cram a lifetime of drama into one long, magical day; they must feed, fight and rear their young in this brief window of plenty. Summer is a tough time for the polar bear family, as their ice world melts away and the cubs take their first swimming lesson. Some bears save energy by dozing on icy sun beds, while others go egg-collecting in an Arctic tern colony, braving bombardment by sharp beaks. There are even bigger battles on the tundra; a herd of musk oxen gallop to the rescue as a calf is caught in a life and death struggle with a pair of Arctic wolves. But summer also brings surprises, as a huge colony of 400,000 king penguins cope with an unlikely problem - heat. The adults go surfing, while the woolly-coated chicks take a cooling mud bath. Nearby, a bull fur seal is prepared to fight to the death with a rival. Fur flies as the little pups struggle desperately to keep out of the way of the duelling giants. Further south, a minke whale is hunted amongst the ice floes by a family of killer whales. The dramatic chase lasts over 2 hours and has never been filmed before. The killers harry the minke whale, taking it in turns to wear it down. Eventually it succumbs to the relentless battering. Finally, comical adelie penguins waddle back to their half a million strong colony like clockwork toys. The fluffy chicks need constant feeding and protection as piratical skuas patrol the skies. When an unguarded chick is snatched, a dramatic "dogfight" ensues.

A dramatic journey along the coasts of South America, from the Falklands to the tropical Galapagos. The cold currents create rich fisheries, and support such diverse marine life as dolphins, killer whales, sea lions and albatross. But the most biquitous creatures are the penguins, which inhabit surprising locations - lush forest, arid desert and even equatorial areas.

Mammals' ability to learn new tricks is the key to survival in the knife-edge world of hunters and hunted. In a TV first, a killer whale off the Falklands does something unique: it sneaks into a pool where elephant seal pups learn to swim and snatches them, saving itself the trouble of hunting in the open sea. Slow-motion cameras reveal the star-nosed mole's newly-discovered technique for smelling prey underwater: it exhales then inhales a bubble of air ten times per second. Young ibex soon learn the only way to escape a fox - run up an almost vertical cliff face - and young stoats fight mock battles, learning the skills that make them one of the world's most efficient predators.

If you're a paleontology buff, this series is for you. And the fun-loving Nigel Marvin provides a great narrative. Explore the prehistoric world in search of sea-based monsters. It focuses on life in ancient oceans during each prehistoric period. Nothing, not the carnivorous dinosaurs of the past, nor the imagined sea serpents and monsters of maritime history, nor the great white shark, salt water crocodile, killer whale and leopard seal of today can compare to the horrifying hunters of the prehistoric oceans.