You will feel a lot more comfortable about going out for a swim or an afternoon boat ride knowing that such behemoths are extinct today!The Dunkleosteus is school bus-sized armored fish with razor sharp bladed jaws for cutting through anything in its path. The mighty Liopleurodon is a true monster, largest and most powerful of the Pliosaurs. The deadly Mosasaurs where the real sea serpents of their day, and some where large enough to dispatch an adult tyrannosaur easily.

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.

This episode examines those birds whose sustenance comes from flesh and their methods of hunting. In New Zealand, Sir Attenborough observes Keas, parrots that do not eat meat exclusively, raiding a shearwater's burrow for a chick. However, it is the dedicated birds of prey, such as owls, buzzards, eagles, falcons and vultures, to which much of the programme is devoted. In order to spot and pursue their victims, senses of sight and hearing are very acute. Vultures are the exception, in that they eat what others have left, and once a carcass is found, so many birds descend on it that the carrion seems submerged beneath them. The Turkey Vulture is an anomaly within its group, as it also has a keen sense of smell. Eagles defend their territory vigorously, and a pair of sea eagles are shown engaging in an aerial battle. The Galápagos Hawk hunts Marine Iguanas, but can only do so when its quarry is vulnerable, during the breeding season. The African Harrier Hawk has adapted to extracting burrowing animals by virtue of an especially long, double-jointed pair of legs. By contrast, a shrike is not equipped with the requisite sharp beak and talons needed for butchery, and so dismembers its kill by impaling it on the thorns of acacias. The Lammergeier eats bones, and will drop them on to rocks from a great height in order to break them down to a digestible size. Also featured are the Eurasian Sparrowhawk, Goshawk and Peregrine Falcon.

Immerse yourself deep into the ocean in search of the most dangerous predators in our seas. Unveil the mysteries of these fascinating and skilled hunters. Razor-sharp teeth and lightning-fast reactions rule in this unforgiving environment. Are you ready to discover the facts behind the myths and legends about sharks, barracudas and moray eels? Shot in 3D, this documentary introduces you to the Kings of the Sea in an unprecedented way

Ewan and Charley swap their e-Harley Davidsons for plane first and follow it up with a journey by ship to Panama. McGregor's bike needs some repairs and will be fixed by the time they reach Costa Rica. The ship they travel in with the bikes looks like a beaten-down vessel that raises genuine concerns about making the journey in one piece. The boat crew looks sharp and proactive while trying to make the show crew's journey as comfortable and safe as possible. The episode also introduces Nuqui, one of the wettest regions in the world where the ship quickly makes a pitstop to fuel up on essential supplies.

Be it foxes on city streets or wolves on the tundra, canines rely on sharp senses, athleticism and fierce determination to punch above their weight. But the real secret of their success is much more surprising. It's a story of their intimate side. It's what makes every dog, from pet pooch to wild dogs, one of the family.