"Birds today are the masters of the skies." "But they were not the first creatures to fly," "and they are certainly not the biggest." "The first large animals to leave the ground were so extraordinary they're almost beyond imagination." "They were reptiles." "Pterosaurs." "They evolved into a huge variety of species." "Some, the size of aeroplanes, were the largest creatures ever to fly." "They could travel half way around the world in a single flight." "And the pterosaurs' extraordinary abilities enabled them to dominate the skies of the prehistoric Earth for a 150 million years." "But, why did these magnificent beasts take to the air in the first place?" "How did they fly?" "And why, after such success, did they vanish?" "Something very remarkable happened around 220 million years ago." "The planet then was a very different place." "It was much drier, for a start, but, in the tropics there were rainforests, and then, as now, they were the focus of a great deal of varied wildlife." "In the detail however, they were very different." "Most notably, there were no large creatures in the air." "No bats." "No birds." "The stage was set for a remarkable advance in the history of life." "At that time, the only animals that could fly were insects." "They were tempting food for reptiles." "But if a reptile were to catch them, it, too, would have to take to the air." "And a hint, of how they might first have done so can be seen in an animal that is alive today." "This little lizard called Draco, is found throughout the forests of Southeast Asia." "And it must certainly have had, in the far distant past, lizard ancestors and cousins that looked very much like it." "Like them, it finds it food, insects, throughout the forest." "And to do that, it has to get around." "And it has a very interesting way of doing that." "Draco is an excellent climber." "Light in weight and with powerful gripping claws, it can run along the branches of the highest trees in pursuit of its prey." "But Draco faces a problem." "How can it travel from one tree to the next without going all the way back down to the ground and then up again?" "The way it has evolved of doing so, gives us a clue as to how early reptiles may first have taken to the air." "It jumps." "But it does more than just leap." "It extends the width of its body by opening flaps of skin along its flanks," "and they enable it to glide." "Draco may give us the right idea as to how gliding, flying, amongst the reptiles started." "But one thing is certain." "Flapping flight, powered flight, remained the preserve of the insects for a very long time." "And then, one group of reptiles developed even that." "And the evidence of how they did so is really very intriguing." "This is Dorset, on England's south coast." "And this is where my journey into the past begins." "A 90 mile stretch of shoreline here can tell us a lot about the evolution of flight." "This is the Jurassic Coast." "Its rocks are full of fossils of prehistoric creatures, including evidence of the first backboned animals ever to fly." "But wasn't until the 1 9th century that scientist started putting together those clues to form a detailed picture of one of the most dramatic periods in the whole of the history of life." "And they had an unlikely ally." "A middle aged woman from the local town, who used to come out to scour these cliffs for those clues." "She'd come in all weathers, but particularly, after there had been heavy storms, which might have removed some section of the cliff, and so exposed specimens that no one had ever seen before." "Her name was Mary Anning." "Mary is, for me, the heroine of this remarkable story." "She had an almost unbelievable talent for unearthing fossils." "In the early 1 800s, science was still the preserve of men." "Yet, what she managed to unearth, brought academics flocking to her hometown of Lyme Regis." "So extraordinary were her achievements that some called her, "The Princess of Palaeontology"." "When you consider Mary Anning's status, a woman from a working class background, with no formal education to speak of, it may seem strange that she acquired such a prestigious reputation, until, that is, you see what it was that she discovered." "The Natural History Museum in London." "It holds one of the most comprehensive collections of fossils in the world." "And those Mary Anning discovered are among the very best, and the most important." "A whole section of the museum is filled with her finds." "Most of the creatures she collected were giant aquatic reptiles, fish eating monsters that dominated the seas." "But she found other things, too." "One of them in particular is the key to our story." "In 1828," "Mary Anning made one of her most sensational discoveries." "This is it." "It's a small animal, but its head is missing, and its spine is missing, but what remains is fascinating." "Here's its pelvis, its upper leg, its lower leg, and there is its foot with its toes." "And here is its arm, which ends with a hand with fingers." "Except that one of these fingers is hugely elongated, it runs all the way along here." "And Mary Anning probably realised what that meant." "It meant that that long finger supported a wing." "And as more specimens were discovered, it was realised that this was certainly a reptile with a wing, so, it was called "Pterosaur"." ""Winged lizard"." "Mary Anning had found the blueprint for the first large animals ever to fly." "A creature that set the pattern for a whole new phase of aerial evolution." "It lived 200 million years ago, at a time when the planet was very different from today." "Much of it was tropical." "The early dinosaurs were rising to dominance." "And flying high above them were the pterosaurs of the kind whose bones Mary Anning had discovered." "Dimorphodon." "Up here in the trees, they were safe from those predatory dinosaurs down on the ground." "And there were plenty of flying insects for them to catch and eat." "But these early flying reptiles were pioneers." "And it maybe that, just occasionally, they were a little clumsy on the wing." "Sometimes, as their bodies lay on the sea floor, they were slowly covered with mud, that over millenia, eventually turned to stone." "Fossils of pterosaurs have been discovered in many parts of the world." "In Africa, Asia and South America." "But the very first were found here, at Solnhofen, in Southern Germany." "This limestone has been quarried for building purposes, since Roman times." "But those who work here sometimes find something far more valuable than just roof tiles." "The discoveries made here make this one of the most important places in all over the world for anybody who's interested in pterosaurs." "And the perfection of their preservation has enabled us to unlock many of the secrets about how these wonderful animals flew." "The Solnhofen limestone formed on the floor of a shallow tropical lagoon, protected from the currents of the open sea by a reef." "So, its waters were still, and they were few currents to disturb the rotting bodies." "The rock here is really extraordinary." "When it's fresh, it's very solid, hard building stone." "Excellent." "But when the frost gets at it, it begins to split." "And when it's really weathered, you can open blocks of it like leaves of a book." "Like that, for example." "And sometimes there's something written on these leaves, but mostly" "nothing." "And maybe for..." "I was going to say, "Maybe there's nothing."" "But, on this one, there's a perfect little ammonite, a shellfish." "This quarry has produced so many fossils that the town's castle has been turned into a museum to house them." "The majority are sea creatures, but sometimes, there are animals that fell into the water from the skies above." "Pterosaurs." "Here is one that did." "It's a kind called Rhamphorhynchus." "Not only are its bones still connected, as they were in life, you can even see something of its soft parts." "This one of the most perfect pterosaur fossils ever found." "And it's a miracle, bearing in mind it's a 150 million years old, and yet it's complete in all the tiny details." "It had a long bony tail," "long toes on its feet." "Its spine and its ribs still connected." "Its jaws have long teeth which would've enabled it to snatch fish from the surface of the lagoon." "But the most fascinating parts of its anatomy are its wings." "They are supported as in all pterosaurs by a hugely elongated finger." "This is the wing membrane, which, in life, would have been less than a millimetre thick, and yet, it's so perfectly preserved you can see within it all the tiny details of little structures that would have given that membrane strength." "There are rows of tiny fibres called actinofibrils, which may have given it precise muscular control right across the wing surface." "You can also see from this fossil how pterosaurs managed their wings when they weren't flying." "Here, at the base of this long finger, is the miracle joint, which enabled the pterosaurs to move their fingers in any direction." "And that was a huge advantage because it allowed them to fold up their wings when they landed." "The pterosaurs had evolved a brilliant first solution to the problems of travelling through the air." "But they were about to become even better aeronauts." "About 50 million years after the first winged pterosaur came something much more advanced." "It lived in a region of the planet that is now China." "Its skeleton was unearthed by one of the world's leading experts on pterosaurs," "Dr David Unwin." "So, here's one of the pterosaurs that we found last year in China." "He named it after Charles Darwin." "Darwinopterus." "Gosh, it's very beautiful." "It's almost complete, isn't it?" "It's absolutely complete." "We can tell that from things like this long tail, that we're dealing with a rather primitive kind of pterosaur." "These are classic features of that group." "But revelation came when we looked at the neck, and in particular at the skull, because that's quite astonishing." "Why, it's huge, isn't it?" "I mean, that's... longer than the body." "The jaws themselves are really very powerful and it's got some big pointed teeth as well." "This is a skull which looks like that of a really advanced pterosaur." "But, the rest of the body looks really quite primitive." "So we've got this weird mix of characters, primitive and advanced." "This is a little bit like Frankenstein's monster." "The big head and pointed teeth of Darwinopterus makes it clear that this was a predator." "So it must have been very agile in the air." "But, this pterosaur wasn't just eating insects." "Pterosaur wings were clearly very efficient in the air." "But they evolved at a cost." "Using wireframe computer simulations of pterosaur movement," "David Unwin has investigated how they moved on the ground." "What I've done is feed to the vital statistics of this pterosaur into the computer, and build this model that you can see on the screen." "It's easy to see that walking on flat surfaces would have been quite difficult for it." "Did they always move around like that?" "Well, we can try and get him to stand just on the hind limbs alone, like a bird, but when you do that, the thing you can see is not very well balanced at all." "Looks quite unstable, and worst still, the tail is actually catching on the ground." "So, now we can see him standing, in this four-legged pose." "The winged membranes, which are attached to the hind limbs, get in the way somewhat." "It doesn't look all that comfortable on the ground." "And in fact, when we look at the claws on the hands and the toes, we find that they're really not well suited to life on the ground at all." "Where's he off to now?" "And now we see, it looks a lot more happy, just hanging up there, just as they would have done on trees and cliffs..." " Yeah." " ...back in the Jurassic." "So, early pterosaurs, with their long tails, probably spent most of their time hanging from vertical surfaces like cliffs and the trunks of trees." "But, if they were to spread beyond those environments, they would have to change the shape of their bodies." "This fossil is 140 million years old." "It has the enlarged head of an advanced pterosaur, but its tail is different." "It's become much shorter." "And this short-tail species wasn't alone." "It was clearly a very successful modification." "There were many like it, with these new style short-tails and reduced hind flight membranes." "Here, in France, at Crayssac, in the valley of the Lot, discoveries have been made that give us a unique insight into the lives of these new style pterosaurs." "The short-tail creatures that appeared, are called "pterodactyls"." "This is one of them." "The loss of the tail had given them greater mobility in the air, but at the cost of a certain amount of stability." "But also, the membrane between the two legs, have split." "And that too, probably helped them in steering." "But flying was only part of their lives." "The sea in which these limestones formed, was here quite shallow." "And not far away, there was a beach." "And there, pterosaurs left particularly vivid evidence of their presence." "Fossils, not of the animals themselves, but traces that only revealed themselves after dark." "The best way to look for fossils here, is at night." "Because then, you can control the light, and makes sure that it shines almost horizontally across the surface of the rock." "And so, expose every tiny little mark and ripple." "The muddy sand here was once soft, but firm." "And in consequence, it retained the tracks of animals that moved over it." "In fact, there are so many of them here, that it seems that this particular beach was a kind of pterosaur runway." "Here is a track that extends for 11 feet, between three and four metres." "The most distinct tracks are made by the feet." "There's one, there's another, there's another." "But, outside these footprints, there are other, rather more indistinct prints, which are made by the knuckles of the hand, without the little finger, which, of course, is enormously extended, and it supports the wing membrane," "and is cocked up in the air." "There's one, there's another, there's another, and there's another." "And when you examine the footprints, you can see that they have four toes." "Not five, four." "That's a sign that these were made by short-tailed pterosaurs." "And the distance between the feet varies." "Sometimes it's relatively short, sometimes it's longer." "And that's because these animals moved at different speeds." "When they were moving at speed, they took bigger strides." "So, these show, this marvellous deposit shows that short-tails, on the ground, were really very nimble indeed." "And that's probably because the membrane between the legs, in the short-tails, has been divided." "So the legs have more freedom." "So, the short-tail species were able to get about on the ground pretty well." "And that was important, because this enabled them to exploit new sources of food." "Indeed, it might be the case that the future of the pterosaurs was assured, for some time at least, not by their ability to fly, but their ability to walk." "This ability to walk had a profound effect on pterosaur evolution." "There's evidence that from this time on, all kinds of new species began to emerge that fed on a wide range of different food." "The short-tails proceeded to diversify into a great number of different forms, finding food in a great variety of places." "And you can tell what they ate by their skulls." "This one for example, has, what look like a pair of tweezers on the front, and very rounded teeth." "It is thought to have been able to dig out, cockles and mussels from the sand and crush them." "So, this was walking on the ground." "This one, on the other hand, found its food while it was on the wing." "And that it dipped down and seized big fish, which it stabbed with these teeth." "And then, carried off in its jaws to rip apart, perhaps on the ground." "Others had dense rows of teeth that were so thin they were scarcely more than bristles." "That enabled these animals to use their jaws like sieves to filter out small crustaceans such as shrimps and other small morsels." "And some lost their heavy teeth altogether and evolved beaks." "Adaptations like these were probably influenced, not only by the different ways of eating, but by the universal need of all flying animals, to keep their weight down to a minimum." "So, by about 80 million years ago, the short-tailed pterosaurs dominated the skies." "Not only were they catching flying insects in mid-air, they were snatching food from the surface of the seas and filtering it from the shallows." "This was the pterosaur's heyday." "One species in particular symbolises their success." "It's called Pteranodon." "It was the most common pterosaur of its time, and it was also very big." "It measured about 18 feet from wingtip to wingtip." "But how did such large animals manage to stay airborne?" "You can see the answer in this fossilized bone." "It's hollow." "It's been treated with acid, so that you can see inside it." "And inside, it's got a network of struts to support the bone." "So, it was very, very lightweight." "The full extent of these cavities, is revealed by x-rays." "And a cross-section shows that they had another and very valuable function." "This is the upper arm bone of a pterosaur." "And at the top, it has a hole." "And that's a clue, as to how they generated power." "Because it was connected by a tube to the lungs, and internally, to these cavities." "So, it was in there, that the pterosaur was able to store air and the oxygen that it contained." "And from that, it could get the power when it really needed it." "With all these ingenious adaptations for flight, the pterosaurs now had the freedom of the skies." "But, a new kind of flying reptile had been evolving away from the coast, in the forests farther inland." "And its arrival would have enormous consequences for the pterosaurs." "In that remarkable quarry in Germany, another amazing discovery was made." "Among all those shellfish, shrimps and fish, something utterly new had appeared." "There can be no doubt about what it is." "It's a feather." "And a few months after its discovery, a quarryman found the fossil of the animal to which it must have belonged." "Its outstretched wings made it quite clear to anyone that this was an animal that could fly." "They called it Archaeopteryx." "And this is what it may have looked like in life." "The feathers on its wings are strong and rigid." "So, they don't need to be attached to the legs, as membranes do, and it leaves the legs free, so that they could run." "The head doesn't have a lightweight beak, like modern birds." "But it's still very much the head of a reptile with bony jaws and teeth in it." "And, the tail, too, has a line of bones running down its legs, just like a lizard's tail." "So, this is half reptile, half bird." "We now know, that Archaeopteryx was not alone." "There were several different kinds of feathered reptiles living about this time." "Their skeletons are very rare, perhaps because they lived inland, where conditions for fossilization were not as good as they were in the coastal seas." "But it's clear that the pterosaurs now had rivals in the sky." "And, perhaps, in response, they began to evolve in some quite extraordinary ways." "In Texas, aeronautical engineers are trying to understand the pterosaur, that is surely one of the oddest creatures that ever flew." "It had a simply enormous head crest." "It's called Tapejara." "This reconstruction of it is the result of seven years of study by evolutionary biologist Dr Sankar Chatterjee." "He used data from fossils discovered in Brazil, and he has advanced some revolutionary theories as to how this animal used its amazing body." "This huge crest was developed in some kind, like a motion sensor, so they could pick up if there's a disturbance in the wind, and they could relay it to the inner ear, which is a very large ear," "and which is like a gyroscope." "So, nerves in this go down into the brain?" "Brain." "So, any factor working on this is going to be relayed to the brain." "Relayed to the..." "It's almost like autopilot device." "You know, it's a sensor, also, it is a beautiful steering device." "This is much more extreme than any other." "Extreme." "Right." "So, what could this do that the others couldn't do?" "One of things, as I said, they could turn very quickly." "So it's like steering, it's like a rudder in front." "So, this enabled them in fact, to be more aerobatic?" "Aerobatic, yes." "Some specimens of Tapejara show that it had fur." "And that suggests that it was warm-blooded." "Warm blood enables an animal to generate the abundant energy that's needed for aerobatics." "But, Dr Chatterjee has another imaginative and controversial interpretation of Tapejara's bizarre anatomy." "What we have found special in this model, we did some simulations." "That is, when they simply raise their wing, they could also sail." "You think that it could not only fly in the air, but it went down to sail on the sea, is that right?" "There's a very good chance when they land on water during their foraging, because they are probably hot-blooded, they need lots of food, lots of fish." "And during the foraging, maybe the whole daytime, you know, they will just eat and eat and eat." "So, how to move?" "How to cover the large area?" "And it looks like that it was a beautiful sailing animal." "Just like a sail boat." "Did the head crest have a function when it was on the water?" "I think so." "Basically, when they're sailing, the head crest would be just like a jib, you know, the very front sail of a sailing boat." "And these two would be the main sail." "And simply by, you know, arranging these three sails, they could really sail very fast." "Swans and geese today sometimes lift their wings, to catch gusts of air." "A behaviour called 'goose-winging"." "So perhaps, Tapejara did indeed do something similar." "But big head crests had a much more likely function." "There are clues of what that might be in animals alive today." "Like this colony of gannets on Bass Rock, off the coast of Scotland." "Pterosaurs doubtless would have lived in great groups around the ancient coastlines." "And living in tightly packed communities, then, as now, must have led to all kinds of dramas." "Just as it does in communities like this one." "Gannets nesting close to one another squabble with their neighbours over food and territory." "Pterosaurs doubtless also competed with one another, for the attentions of the opposite sex." "So, perhaps Tapejara used its huge head crest in displays to its mate during the breeding season." "And indulged in the same sort of strutting performances that so many birds do today." "After their courtship, pterosaurs, just like birds, laid eggs." "This fossilized egg, which is about the same size as one of these gannet eggs, is actually the egg of a pterosaur." "And although it's squashed flat, it's marvellously preserved, so you can see details of the bone inside." "The head, as you'd expect with a bird head, is quite well formed." "It's amongst these massive bones here." "But whereas a bird's wings will hardly be formed at this stage, here, the pterosaur wings have got these well formed bones in them." "And that leads us to one extraordinary conclusion." "A pterosaur chick, when it hatched, was almost immediately able to fly." "The bones of the pterosaur embryo reveal another extraordinary fact." "They develop in a way quite different from birds." "And what is more, they continue to do so, even after the young have hatched." "This led to some species becoming gigantic." "Here, in the south western United States, close to the Mexican border, evidence was found of the largest animal ever to fly." "A pterosaur so gigantic, that for years, some scientists refused to believe that it could have existed." "Seventy million years ago, the area was a hot, lush floodplain." "I've come here to meet fossil hunter, Doug Lawson." "And here, Doug made one of the most remarkable discoveries in the history of pterosaur research." "On the side of the sandstone hill was this one isolated ball." "And you might have thought, "Well, it's just another dinosaur,"" "except the material of this animal was very thin, very light individual." "And, uh, it was difficult because, actually, if you thought it was pterosaur, then the bone that you were gonna be comparing it to was usually the size of a grain of rice." "And this bone was bigger than a grapefruit." "And it was covered with sandstone, so it was very difficult to see what it was." "But I finally figured out that it was the wrist of the animal." "And pterosaur wrists are unique." "So, given that, when we had these other pieces of bone that we discovered in the location," "you'd come to understand how big that was." "This is just the upper arm bone of the specimen." " This..." " Yeah, yeah." "And looking at this you realise," ""Wow, we have something that's dinosaur sized." ""But it's a pterosaur."" "Now, you could not have prevented yourself from saying," ""How big is this?"" "Oh, yeah, right." "Then you'd say, "Wow..."" "Okay, we've..." "So, based on what we have, the estimate was about 50 feet." " Wingspan?" " Yeah." "Yeah, 50 foot wingspan." " I mean that..." "That is gigantic." " Oh, yeah, definitely." "Mind blowing." "Did people believe it?" "Well, there was some question." "No other pterosaur was even half the size of this one." "And the fact that something so large that could fly, there was almost an aerodynamic question of whether this could even be." "It was a truly astounding discovery." "His creature had wings that were so large, they could easily have spanned the width of this building." "It lived 70 million years ago, during the Cretaceous period." "It stood 20 feet high." "So tall it could look a giraffe in the eye." "This was Quetzalcoatlus." "Named after the Serpent God of the Aztecs." "It was probably a scavenger." "Using its long neck to probe deep into the carcasses of dead dinosaurs." "Any small animal foolish enough to get in its way was likely to meet a grizzly end." "But how did the giant Quetzalcoatlus get off the ground?" "The answer may be found inside the pterosaur arm bones." "There are two things you have to get right, if an animal the size of a giraffe, like Quetzalcoatlus, is to get into the air." "Weight and power." "And a close examination of the bones, show how the pterosaurs did that." "A scan of the arm bone of Quetzalcoatlus shows that just like those of other pterosaurs, it was hollow." "This animal was very lightweight." "It may have been the size of a giraffe, but it was no heavier than two human beings." "But at the very top of the arm, the bone is very different." "All these supporting struts line up in one direction." "And that gives us a clue as to how the animal got airborne." "The upper arms were reinforced so that they could withstand the sudden burst of great power without breaking." "The animal used all four of its limbs as a giant catapult." "To launch its body skyward at 35 miles an hour." "It used a quadrupedal launch." "But how did it actually fly?" "There is a practical way of finding out." "A modern glider is about the same size as that giant pterosaur." "It too, has long slender wings." "And it too, is extremely light." "This flying machine is so lightweight, it doesn't even need an engine." "All it requires is a tow to get it into the air." "This is the nearest I will ever get to experiencing the magic of Quetzalcoatlus in flight." "With its giant wingspan, this was the largest animal ever to fly." "Quetzalcoatlus kept its wing beats to a minimum." "It was a living glider." "And it had much more detailed control that even the most advanced and sophisticated of modern aircraft." "We are controlling our flight, using at least in part, our tail." "However, whereas powered aeroplanes have tails and birds have tails, advanced pterosaurs like Quetzalcoatlus didn't have a tail." "So, steering must have been much more difficult, and would have required very considerable brain power." "But there was, people think, a payoff to that." "Because without a tail," "Quetzalcoatlus was even more manoeuvrable, than we are in this." "Quetzalcoatlus doubtless used many of the techniques employed by human glider pilots." "To maintain our height, we need to find a thermal." "That's those columns of warm air that rise from patches of the landscape, that heat well in the sun, like patches of rock." "You can tell where they are, because white fluffy clouds form at the top of them." "And there's one over there, and we're going to have to get to it if we're going to maintain our height." "It's been estimated that by exploiting thermals," "Quetzalcoatlus could travel some 10,000 miles in a single flight." "And that is almost half the circumference of the entire planet." "It might even be that like some eagles today, these flying giants undertook long migratory journeys every year." "And so, a 150 million years after they had first appeared, the pterosaurs were at their most spectacular." "And then, suddenly, they vanished." "A meteor that crashed into Earth 65 million years ago is often blamed for the extinction of the dinosaurs and the pterosaurs." "But the truth is that their fate was already sealed millions of years before that moment," "by the early birds that had been evolving in their shadow." "It was the birds that rose from the ashes of that meteor." "They occupy all the niches that the pterosaurs once did." "So, why did birds survive and the pterosaurs die?" "Birds had one great advantage over the pterosaurs." "Their rigid flight feathers meant that their wings had no need to be anchored to either their flanks or their legs." "So, birds could run, and walk, and pounce, whatever they needed to do, to collect their food in almost any of the land's environments." "No pterosaurs, encumbered by their skinny wings, could wade like flamingos." "Birds today have evolved into thousands of different species, flying with many different techniques." "But it was the pterosaurs that were first into the air." "It was they that solved the fundamental problems of flight." "And in their prime, they reached a grandeur, that the birds still can't match." "The dynasty of the pterosaurs lasted over a 150 million years." "We human beings have only been around for about two." "But only now, are we beginning to appreciate to the full the wonders and the splendours of those pioneers of flight, the pterosaurs."