"He ruled the skies supreme, flying far and wide over the lands of the dinosaurs." "This is the story of the last journey" "This is the story of the last journey this giant ever made." "It is the start of a time called the Cretaceous." "The movement of the continents is not only breaking up the landmasses, but it continues to push up sea levels." "This has opened new seaways and coastlines." "(Squawking)" "Where once there was solid land, now there are ragged cliffs, buzzing with an abundance of flying reptiles called pterosaurs." "Pterosaurs have been here for 100 million years." "Many species are huge." "Wingspans of six metres and more are common." "But there is one species that dwarfs them all." "He is 0rnithocheirus - 12 metres from wing tip to wing tip and a body bigger than a man's." "The undisputed king of the skies." "This giant is over 40 years old." "Most of his life has been spent wandering the globe," "Most of his life has been spent wandering the globe, in search of food, but every year, there is an interruption to this nomadic life." "It will soon be time to find a mate." "0n the rocks, the mating season for another pterosaur is under way - the bizarre-looking Tapejara." "Pterosaurs' wings are thin membranes of skin that stretch from elongated fingers on their forelimbs to the ends of their hindlimbs." "Their bones are hollow and light." "They are masters of the air, but on land they are cumbersome, with their legs joined up by the wings." "Squatting on all fours, the males try and claim an area from which to display to the females." "They show off their colourful crests until one competitor backs down." "A large crest is also a lure to the females." "A potential mate soon makes a cautious approach, her head dipped in submission." "As in any competition, there are losers." "Unable to secure himself a good display patch, this male is perilously close to a blowhole." "Down here, he has little chance of attracting a mate." "(Honking call)" "Instinct tells the 0rnithocheirus that it is time to move on." "He must return to his breeding site in Europe, on the other side of the world." "For this giant of the sky, it will be the last great flight he ever makes." "What he is about to undertake is the most astounding journey in the animal kingdom." "From the shores of the great southern continent, he will travel to North America, cross the Atlantic seaway, and fly on to the islands which mark where Europe will one day be formed." "Spread out below him will be the majesty and spectacle of a world ruled by dinosaurs." "In just a few days, he reaches the southern tip of North America." "Below him, a column of Iguanodon stretches along a beach, grazing the edge of a dense forest." "A thousand tonnes of dinosaur are on the move." "Hundreds of mouths are searching for a fresh place to satisfy their enormous appetites." "The young play around the adults." "The young play around the adults." "Although these herbivores walk on four legs," "Iguanodon can run on just two." "This makes them quite nimble, certainly more so than the lumbering plant-eater, Polacanthus, that is accompanying the herd." "(High-pitched shrieking)" "The wall of flesh travels slowly onward, following the path of the 0rnithocheirus, but there is a setback ahead." "(Thunder)" "The climate in the time of the dinosaurs is warm and tropical." "There are only two seasons - dry and wet." "Now is the time of year for tropical storms." "In moments, the short stretch of coast is drenched - welcome relief for thirsty plants and lean rivers, but it is a disaster for a migrating pterosaur." "The 0rnithocheirus is grounded by the heavy rain, frustrating his urge to get to the breeding site." "He shelters as best he can - the downy fur on his body must be kept dry." "For the Iguanodon herd, the rain is no hindrance." "These are among the most successful dinosaurs on the planet, populating every continent, thriving on a variety of vegetation." "The river estuary provides them with an ideal break in the forest." "There is fresh water and the banks here are thick with lush podocarp scrub and tree ferns." "0ne reason Iguanodon are so successful is they have a new way of tackling plants." "Most dinosaurs can only crudely slice food with their teeth," "Most dinosaurs can only crudely slice food with their teeth, but Iguanodon are the first herbivores to have back teeth that can grind up vegetation." "This ability to chew speeds digestion of even the toughest plant material." "The forests near the equator are also witness to another landmark in evolution." "The first simple flowers have arrived, adding a dash of colour to an otherwise green world." "It is the start of a new relationship with insects." "Attracted by the colour and smell, this wasp is feasting on pollen." "It will unwittingly spread it to other flowers, speeding up the plant's reproduction." "The plants that have evolved this feature are flourishing, and soon will dominate the flora of the world." "The next day, the weather starts to improve." "The 0rnithocheirus waits impatiently in his cave, and busies himself with grooming." "He is plagued by parasites that bite vessels on his wing membrane." "If he is to find a mate, he must be in prime condition." "He has to keep the parasites in check." "In the morning air, smaller reptiles are now out on the wing." "But the 0rnithocheirus is so large, he must wait until the heat of the day creates warm updraughts of air, strong enough to lift him." "But time is short." "His body is already showing signs of readiness for mating." "Faint colours have started to bloom on his beak's display crest." "At last, he can resume his epic journey." "For thousands of kilometres, he follows the coast of North America." "Like all giant pterosaurs, he uses his enormous wings to ride on the warm air currents that rise over land." "His whole body weighs less than 100 kilograms, and this helps him glide effortlessly over huge distances." "But soon he must face open water." "This is the young Atlantic." "It is still only 300 kilometres wide." "To reach the other side, he'll need all his gliding skills to exploit air currents that form over waves." "Along the way, he must feed." "But flying low brings its dangers." "Hungry monsters watch him from below the waves." "An entire day on the wing, and he has arrived on the most western of Europe's islands." "Again, the landscape is dominated by a huge herd of Iguanodon." "But this time, it is a larger European species, up to three tonnes apiece." "These animals are again accompanied by a spiky Polacanthus." "These armoured herbivores are often found around Iguanodon herds, presumably for mutual protection." "There is safety in numbers." "(Growling)" "They are being watched by a pack of carnivorous Utahraptors." "For the moment, they are biding their time." "Meanwhile, another conflict is looming." "A small pterosaur fishes the waters of the lake." "Its success has not gone unnoticed by 0rnithocheirus." "The giant turns bully." "Under cover of the pencil pines, a female Utahraptor has been stalking." "Her chosen prey are the Iguanodon." "Somewhere close by are the rest of the pack." "(Low growling)" "With lethal claws, this five-metre killer is well-armed." "And long fingers help her to latch on to swift-moving larger prey." "(Bellowing)" "(Hissing)" "(Bellowing)" "Raptors have the short legs of a sprinter and do not pursue their prey for long." "This one saves her energy for later." "Eventually, the herbivores lose their nervousness, and they start to move on." "As the Iguanodon file down to a lake to drink, a Polacanthus lags behind to gorge on conifers, and becomes separated from the herd." "The Utahraptors soon reappear, tails held rigid for balance, but the Polacanthus displays his formidable defences." "For a predator, there are far easier meals nearby." "The whole herd has reached the lakeside." "In the background, the 0rnithocheirus sits safe on his rock." "The raptors are closing in." "The Iguanodon sense the threat and start to get nervous." "After one unsuccessful attack, the raptors are being more cautious, and it is paying off." "They are within striking distance." "(Guttural roar)" "This is the first kill they have made for over a week." "They will eat as much as 100 kilograms each in one sitting." "The youngest of the Utahraptors hovers nearby." "There is a pecking order to this feast, and the large adults come first." "However, the youngster is hungry and he tries his luck." "(Snarling)" "The response from the adults is immediate and intimidating." "This is not a confrontation he can win." "High above, the 0rnithocheirus leaves these killing fields for a safer place to pass the night." "He finds what appears to be an ideal spot to rest, before his final push to the mating grounds." "But from within the dense forest, he is being watched... by relatives of the raptors." "These, though, are birds - flying dinosaurs that share the same ancestors as the carnivorous raptors." "They have evolved feathers which turn their arms into wings." "At this time of year, they have eggs to protect, and the presence of the intruder sets off a chain reaction of aggression." "Next to the 0rnithocheirus, the birds look no bigger than insects." "Their feathered wings are more resistant to damage than the skin membrane of the pterosaur, especially among branches and twigs." "In the future, the pterosaurs will surrender the skies to the birds." "He eventually reaches Cantabria, which will one day form Spain." "He is exhausted by his 14,000 km journey." "Ahead lies the mating ground." "Every year of his adult life, he has returned to this same spot to mate." "The beach is full of male 0rnithocheirus competing for space." "As the old male approaches, he knows that the nearer the centre of this intimidating throng, the more attractive he will be to the females." "He heads for the dominant position he has occupied in previous years - right in the middle." "But this time, he faces a challenge to his supremacy." "Again and again, he tries to land, but the males on the ground fend him off." "Eventually, his weariness tells, and he has to land elsewhere." "His position among the males has been usurped by younger animals." "They advertise their vigour and size to warn off rival males, and to attract females out of the air." "For the outcast, the world has been turned upside down." "Now banished to the outskirts of the mating area, he will be lucky to attract a female at all." "(Honking call)" "In the blistering heat of midday, his instincts force him to keep trying." "The females are unmoved." "The centre of the beach." "A female has just landed and submits herself to a male who flashes his red crest to impress her." "Mating itself is brief." "Afterwards, the male will resume displaying" "Mating itself is brief." "Afterwards, the male will resume displaying to attract more females." "The female herself will now leave." "Three days later and, at last, the breeding site is emptying of males." "It is still fiercely hot." "0ur 0rnithocheirus has yet to mate." "Worse still, his fruitless exertions under the blazing sun have taken a heavy toll." "(Weak honks )" "Heat stress and lack of food have all but killed him." "The king of the skies has lost his majesty." "His life has run full circle." "In his time, he travelled the globe, but death finds him here, in the very same place where he first mated some 40 years ago." "0n the beach are others who lost out in this struggle to reproduce." "But nature is seldom wasteful - they have become food for the next generation." "The pterosaurs continued to rule the skies for millions of years, while on land, the dinosaurs spread to every part of the globe." "In the next episode, we will see how they conquered the most extraordinary environment of all - the dark forests of the South Pole." "(Fierce roar and high-pitch screams )"