♪♪ ATTENBOROUGH: London's Natural History Museum is full of wonders.

It's a place where we can get a vivid idea of the great variety of life... that inhabits our planet.

But there are some creatures here that I can never hope to encounter because they are extinct.

[ Dinosaurs roaring ] [ Recording powers down ] GUARD: Ladies and gentlemen, the museum is going to be closing in 5 minutes, so please make your way towards the exits.

Thank you.

ATTENBOROUGH: Tonight, however... ♪♪ ...something magical is happening.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ATTENBOROUGH: It's a big place.

There are 70 million or so specimens here I'm told.

♪♪ And the first I want to look at right now is way up on the very top floor.

The Maori people of New Zealand have legends about huge flightless birds that in the past had roamed their islands.

Stories that many Europeans dismissed as myths.

Until this skeleton was sent here.

It was a giant.

♪♪ The Maori in their legend had called it a moa.

But was it the largest bird that had ever lived?

♪♪ ♪♪ [ Moa squawks ] ♪♪ ♪♪ [ Moa squawks ] There were several different species of moa, but this was certainly the biggest.

It stands three meters tall.

But is this really what it looked like when it was alive?

You can tell how an animal held its head from the junction between the skull and the neck.

If that is underneath the skull, then its neck would have been upright.

But this moa's neck joint is at the back of the skull, so it must have held its neck more horizontally, like this.

♪♪ ♪♪ [ Moa squawks ] ♪♪ So, was the giant moa the biggest bird that has ever existed?

Well, if it craned up its neck, it was almost certainly the tallest.

♪♪ [ Chuckles ] ♪♪ [ Moa squawks ] [ Laughs ] [ Heavy footsteps approach ] But the moas had an enemy and one that was also huge.

It too can be found here in the museum.

This colossal bird was nearly twice as heavy as the most powerful eagle alive today.

♪♪ Not only that, but it had formidable weapons... ♪♪ ...a beak the size of a butcher's cleaver... ♪♪ ...and razor-sharp talons as big as the claws of a tiger.

This flying killer is Harpagornis.

♪♪ [ Eagle screeches ] ♪♪ We know that Harpagornis preyed on moas because moa skeletons have been found with holes stamped through their pelvic bones that exactly match the grasp of Harpagornis's claws.

It was probably even strong enough to cling to a moa's back with one foot while it slashed at its victim's neck with the other.

[ Moa squawks ] But it looks as if this moa is going to escape, for now.

♪♪ Science has revealed the truth behind many a myth, but there is one tall story that is still remarkably persistent.

♪♪ Back in 1951, a famous Himalayan explorer and mountaineer, Eric Shipton, came across some huge footprints in a high snowfield that looked as if they'd been made by some kind of giant ape.

Shipton's Sherpa companions had no doubt about what had made them.

A Yeti.

An abominable snowman.

Well, there is one small specimen acquired by the museum and kept in its vaults that might just explain those prints.

♪♪ It was found in a shop in Hong Kong that sold Chinese traditional medicines.

♪♪ It was a molar tooth of some kind of ape-like creature, except that it was huge.

The museum only got a fragment.

This is it, but here's a cast of a complete one, and it's six times the size of one of ours.

It was given the name Gigantopithecus, giant ape.

After that discovery, one or two more teeth were discovered, but nothing much until eventually a piece of the lower jaw was found.

The original is now in America.

This is a cast.

But here is the lower jaw.

If this animal had a skull with the same proportions as those of a gorilla, its complete skull would have been this big.

This was a true monster.

[ Tapping, footsteps approach ] ♪♪ ♪♪ ♪♪ ♪♪ [ Low growl ] ♪♪ So, we know a huge ape did exist, Gigantopithecus.

It could well have stood three meters tall, in which case it would have been eight times as heavy as I am.

And if you're as heavy as that, you don't spend much time climbing trees because they won't support you.

So, the likelihood is that his arms are quite short, and he walked upright.

He was bipedal.

I'll get out of the way.

♪♪ [ Low growl ] ♪♪ An upright animal has its head on the top of its spine as I do.

And if that head is to be well balanced, it's better not to have a long muzzle but a rather flat face.

So, if I were to observe Gigantopithecus and it stared back at me, I suspect I'll find its look rather unnervingly familiar.

[ Low growl ] ♪♪ ♪♪ Gigantopithecus is commonly thought to have died out several hundred thousand years ago.

But sightings of the yeti continue to be reported.

So, is it possible that some kind of giant ape, maybe even Gigantopithecus itself, still survives somewhere out in those remote Himalayan mountains?

[ Ape roaring ] ♪♪ Of course, if you want to imagine what an extinct animal looked like, you really need a complete skeleton... and bits of skin and feathers, if you can get them.

And even then, you may well make mistakes.

♪♪ ♪♪ This poor old bird is a dodo.

It once lived on the island of Mauritius in the Indian ocean.

And it's almost certainly the first animal species that human beings actually exterminated in historic times.

And so now we talk about being "as dead as a dodo."

But in spite of its fame, this one is a fake.

Its feathers come from a goose, its feet were modeled on a turkey, and its beak, I suspect, is plaster.

The museum can be forgiven because no skin or feathers of the dodo survive.

Its image was influenced by pictures like this one, painted by a 17th-century Dutch artist, Roelandt Savery.

But he had never seen a living dodo and based his image on accounts by seafarers.

I've often wondered whether dodos actually looked like that.

But unfortunately, they had all disappeared before anyone could get a good look at them.

Until now.

♪♪ [ Laughs ] This funny, dumpy creature is how the bird is usually represented these days.

But I've seen quite a lot of flightless birds over the years, and this one doesn't quite ring true.

An examination of the way its thighs join its pelvis has shown that in life it actually stood much more upright.

♪♪ We now know that its feathers were probably a lot fluffier than in that painting.

We also now know that it was related to the pigeon, and some experts suggest that it made a pigeon-like call -- doo-doo, doo-doo -- which gave the bird its name.

[ Dodo calling ] The dodo probably fed on fruit.

There was a lot of it on the island.

I'll try him with a bit.

Come on!

♪♪ What do you make of that?

[ Laughs ] Ow!

That's a very powerful beak!

In fact, it may well have been adapted for crushing shells and crustaceans for the sake of the calcium.

And there's a female.

Maybe she is another reason why they had such large beaks -- to show off with during courtship.

♪♪ [ Dodo calling ] ♪♪ And here comes a rival male.

[ Dodos calling, hissing ] He could be another reason for having a huge beak -- to fight with in disputes over nest sites.

♪♪ ♪♪ ♪♪ Until now, no one has ever seen a dodo egg, so no one knows how big it was.

♪♪ But after tonight, who knows?

♪♪ [ Dodo clicking ] ♪♪ There are specimens of animals in the museum from every corner of the planet.

The mummified remains of this strange creature were found in a cave in Patagonia, South America.

It was a giant ground sloth.

There are several kinds of ground sloth, and this one had immense claws.

What could they have been used for?

♪♪ [ Ding! ]

[ Low growl ] [ Door squeaks, footsteps slowly approach ] ♪♪ ♪♪ [ Low growl ] These ground sloths probably spent most of their time on all fours.

But nonetheless they were perfectly capable of rearing up on their hind legs.

And when they did that, they probably stood about three meters tall, which is as tall as a grizzly bear, if not taller.

♪♪ But I don't think this one is going to use its claws on me.

♪♪ That dung made it clear that these creatures are vegetarians, so they doubtless used those claws for ripping up plants.

But it's been discovered recently that they used them for something else as well.

♪♪ Something that seems rather surprising for animals of their great bulk.

♪♪ [ Dirt falling ] ♪♪ They dug burrows.

♪♪ ♪♪ Hmm!

♪♪ Huge excavations like this have been found all over Patagonia.

And we know they were made by giant sloths because scratches on the walls of the burrows exactly matched their claws.

Such immense burrows must have been excellent places to take refuge.

And the giant sloths may well have had need of them.

Because there was a truly ferocious predator living alongside them.

[ Big cat snarls ] ♪♪ A great cat with immense, saber-shaped teeth... ...Smilodon.

For me there is no more alarming animal in the whole museum than this.

And its skeleton is perfectly preserved because about 10,000 years ago it wandered into a pool of naturally occurring tar oozing from the ground in California.

In general shape, it was somewhat like a lion, but more muscular, and much heavier.

And those saber teeth were really sharp.

No wonder the giant sloths needed burrows in which to take refuge.

[ Low growling ] [ Sharp note plays ] ♪♪ [ Low growling ] You might think that Smilodon would have caught its prey as a lion often does, by chasing it, leaping on it at speed, and then throttling it, suffocating it with a bite to the neck.

♪♪ But Smilodon stalked its prey, creeping quietly across the plains, until it got really close.

♪♪ And then it pounced!

♪♪ ♪♪ Smilodon couldn't throttle its prey with those huge teeth, and they were too brittle to slash.

They would shatter if they struck bone.

♪♪ Instead, the animal would have first used its great weight to pin down its victim.

Then it would have used its sabers like blades to slice open the soft flesh of its victim's throat.

But these terrifying hunters had a rather touching side to their characters.

Tigers today are solitary hunters, and when one gets too old to hunt successfully, it dies.

But skeletons of really elderly sabertooths have been discovered.

Which suggests that not only did Smilodon hunt in packs, but when members of the family were too old to hunt for themselves, they were allowed to take a share of the kill.

♪♪ ♪♪ The museum is full of creatures that appear terrifying, but which no doubt, if you knew them better, would prove to have quite a charming side to their characters.

But there is one here that would, I think, chill everyone's blood.

♪♪ ♪♪ This is a vertebra from the backbone of a modern snake.

It was a python.

And we know exactly how long it was because it was measured when it was alive.

It was 21 feet long, seven meters.

This, however, is a similar bone from the spine of a fossil snake.

And if this was 20 feet long, how big was this?

Certainly 30 feet, 10 meters, 11 meters.

It was a monster.

But what did it live on in those far distant times?

[ Clank ] [ Sharp note plays ] Maybe, if I follow it, I'll find out what it ate.

♪♪ ♪♪ Science calls this snake Gigantophis.

And it was truly immense.

It was certainly big enough to swallow me.

But would it have eaten human beings?

It's an alarming thought.

♪♪ Well, it might well have done if we had both been around at the same time, but we weren't.

We'd not yet appeared on Earth.

But there was a prehistoric elephant like this one that was unlucky enough to be wandering around the planet alongside Gigantophis about 40 million years ago.

♪♪ Could this monster snake have tackled one of these?

We know from its massive size that it must have been a constrictor... ...and constrictors don't use venom.

♪♪ Instead, having seized an animal with their jaws, they wrap their coils around their prey and squeeze so hard that they stop their victim's heart, and it dies within minutes.

♪♪ I wonder if he realizes that his dinner tonight is a fiberglass model?

I'll leave him to it.

Around 150 years ago when this great museum was being built, pioneer geologists were collecting some huge fossilized skeletons from cliffs on the coasts of Southern England.

They had paddle-like limbs... ferocious teeth... and huge eyes.

They were reptiles, and they were given the name ichthyosaur -- fish lizard.

♪♪ ♪♪ Now it's got skin and flesh on it, you can see how remarkably similar it is to today's dolphin.

It's got the same streamlined silhouette, the same pointed jaws, it's air-breathing, even gives birth to live young.

But surely an ancient ichthyosaur couldn't be as advanced as a modern-day dolphin?

♪♪ [ Dolphin squeaking ] Or could it?

♪♪ ♪♪ Dolphins are mammals.

Ichthyosaurs, reptiles.

Very, very different groups.

They're not at all closely related.

And yet, they both have very similar body shapes.

They're a remarkable example of what's called convergent evolution -- two groups of unrelated animals that have evolved similar bodies to suit the same environment.

But there are some differences.

Dolphins beat their tales up and down, like their cousins, the whales.

Ichthyosaurs, as is clear from their fossils, had tails like fish that beat from side to side.

And dolphins only have two flippers, whereas ichthyosaurs had four.

So, is it possible that ichthyosaurs were as fast in the water and as agile as dolphins, if not more so?

I wonder who would win in a competition?

♪♪ ♪♪ [ Dolphin squeaking ] One kind of dolphin, spinners, can leap from the surface of the water and spin in the air.

♪♪ Maybe the ichthyosaurs could do the same?

♪♪ ♪♪ ♪♪ We know that ichthyosaurs lived and evolved on this planet for many millions of years more than dolphins have done so far.

So maybe ichthyosaurs would have won the competition after all.

Who knows?

[ Dolphin squeaking ] ♪♪ ♪♪ Living around the same time as the ichthyosaurs was another creature that became the subject of great argument when it was first discovered.

This, some might say, is the most scientifically important and valuable specimen in the whole of the museum.

It's a fossil called Archaeopteryx.

But what kind of creature was Archaeopteryx when it was alive?

♪♪ It had two long leg bones, so it must have stood upright.

A bony tail and a long neck.

Its head had bony jaws packed with teeth, like a reptile's.

And its arms had three elongated fingers, each ending with a claw.

So you might think it was some kind of strange, spindly-armed, upright-standing lizard.

Except for one fact.

♪♪ There is evidence of more than just bones on its slab.

Feathers!

♪♪ Archaeopteryx lived some 150 million years ago, long before the appearance of true birds.

Those feathers on its arms certainly enabled it to glide.

But that's not all.

♪♪ It had powered flight.

Marks on the bones show that there were enough muscles attached to them to enable it to flap.

Not only that, a recent scan of its skull showed that its brain would have given it the senses and reactions that are needed for accurate control in the air.

This creature was half reptile, half bird.

It was the first proof that in prehistory there were intermediate forms that linked the big, very different groups of animals that we know today.

♪♪ ♪♪ But while Archaeopteryx could certainly fly, it could also clamber up tree trunks and along the branches, like a tree-living reptile, thanks to those clawed fingers.

♪♪ There were insects flying around at that time.

And Archaeopteryx's teeth show that it was a hunter.

♪♪ ♪♪ And this is Professor Richard Owen, the man who acquired that fossil and built this museum.

Although he disagreed with Darwin's views on evolution, he was one of the great scientists of his time, and he had a particular flair for interpreting fossils.

♪♪ Another group of reptiles dominated the land.

♪♪ They lived long before big mammals, let alone human beings.

There were hundreds, probably thousands of different kinds, and they came in all shapes and sizes.

They are, perhaps, the most famous and dramatic of all prehistoric creatures.

And they were first identified and named here in Britain.

[ Low grunting ] They were the dinosaurs.

[ Grunting continues ] Thousands of people come here every day to look at their amazing skeletons, and to imagine what they must have looked like, and sounded like, when they were alive.

♪♪ [ Roaring ] [ Roaring stops ] ♪♪ It's hard to imagine a time when the world didn't know about dinosaurs.

But until relatively recently nobody knew they had ever existed, let alone that they once ruled the world.

The story of their discovery starts in the 1820s when a doctor named Gideon Mantell, living on the south coast of England in Sussex, picked up something odd in a sandstone quarry.

And this is what he found.

It's clearly a tooth of some kind.

This is its outer surface.

And in shape it's very like the tooth of a living lizard such as an iguana.

Which is why the animal it belonged to came to be called Iguanodon -- iguana tooth.

And with it were a number of other bones.

They were the hips and back legs of some kind of giant reptile.

More of them were discovered, and soon there were enough to get some idea of what the whole animal had looked like.

One odd little bone seemed to have nowhere to go, so the reconstructors put it on the end of its nose, making the animal look like some kind of reptilian rhinoceros.

It was like nothing anyone had ever seen before.

So, a great fossil hunt started in the quarries of Sussex.

And eventually the bones of several different kinds of big animals were discovered.

They were brought here to the museum, Professor Owen examined them, and he decided that they should belong to a completely new kind of animal, an animal he called a dino-saur -- "terrible lizard."

In due course more complete skeletons of Iguanodons were discovered and it became possible to reconstruct them with greater certainty.

Iguanodon could stand upright.

It had small arms and was over 25 feet, seven meters, tall.

And that horn on its nose was actually a spike on its thumb.

♪♪ Before long, new and even bigger species were being unearthed all over the world, from the instantly recognizable three-horned Triceratops to the sensational Tyrannosaurus Rex.

These astounding beasts have inspired and captivated not only scientists, but writers, artists and filmmakers for almost two centuries.

But it was Professor Owen, here in the Natural History Museum, who first identified them.

And his work has been continued here ever since.

♪♪ This is the laboratory, where the museum prepares its fossils for study and for display.

♪♪ It's here that they painstakingly remove the excess rock to reveal the fossils in all their extraordinary detail.

♪♪ This is the fossilized egg of a dinosaur, one of the first to be discovered.

And it was found close to some bones of a sauropod dinosaur.

Sauropods -- this is the model of one -- were gigantic vegetarian dinosaurs that wandered around on four legs.

There are lots of different species of them.

They're found all over the world, and they're the biggest land animals that have ever existed.

Of course, you can't prove that it was a sauropod that laid this egg.

But I would like to think that it was.

The weight of the sand that eventually covered it squashed it.

But if we could see it when it was first laid... ♪♪ ...we would see that it's much rounder than a chicken's egg, more like that of a turtle or a crocodile.

And of course, very much bigger.

[ Rustling ] Hmm!

Sounds like something's in there.

But how will that something make its way out?

Most dinosaur eggs are shell filled with rock.

But not so long ago someone in South America found a sauropod egg and inside there was a baby sauropod.

And on its nose, it had a little egg tooth.

Birds and crocodiles have the same sort of thing.

They need it, as the sauropod did, in order to be able to break out of the shell.

[ Rustling continues ] [ Thud ] Oh!

♪♪ ♪♪ ♪♪ ♪♪ [ Sauropod screeches ] [ Laughs ] [ Sauropod screeches ] We know that baby sauropods were very small and left their nests very early, perhaps to avoid being trampled upon by their huge mothers.

[ Sauropod screeches ] They probably hid in the forest until they grew large enough to join the herd of adults.

[ Sauropod screeching ] ♪♪ Hello!

[ Chuckles ] Well, this is just one leg bone of a fully grown sauropod.

So you can see this little fellow has got quite a lot of growing to do over the next few years.

♪♪ [ Sauropod screeches ] ♪♪ [ Sauropod screeches ] The museum, of course, has the skeleton of a fully-grown sauropod -- of a kind.

And its story is one of kings and millionaires.

Back in 1902, King Edward VII, then-Prince of Wales, saw a picture of a huge sauropod replica, one of the biggest yet discovered, whilst visiting the Scotsman turned American millionaire, Andrew Carnegie, at his castle in Scotland.

The prince immediately said, "Well, I would like one of those," and in those days what princes asked for, they got.

♪♪ And so, in due course, another replica turned up right here in the Natural History Museum.

♪♪ ♪♪ And here it is.

There are two ways of pronouncing its scientific name.

It's either diplo-do-cus or dip-lod-icus.

Either way it's a bit of a mouthful.

So I'm going to use the nickname that is commonly used around here.

This is Dippy.

And what's more, although there's no way of being sure whether it was male or female, I'm going to assume that Dippy was female.

♪♪ But what did Dippy look like when she was alive?

This strangely shaped fragment of a dinosaur called Edmontosaurus was mummified before it was fossilized, so not only the bones but the skin was almost perfectly preserved, and it was covered in small scales.

They didn't overlap like those of a lizard but formed a close-fitting mosaic.

Maybe Dippy was like that too.

But what about her color?

My suspicion is that Dippy, like many large mammals today, such as elephants or rhinoceros, was a general, all-over neutral plain color.

So, if we add a little bit of skin and flesh, we can get some idea of what she actually looked like.

♪♪ ♪♪ ♪♪ [ Low grunting ] ♪♪ ♪♪ So now, after 150 million years, we've got a pretty good idea of what Dippy looked like.

But how did she behave?

♪♪ ♪♪ Well, animals her size and weight must have moved in a rather ponderous way.

And in any case, since she was a vegetarian, as we know from her teeth, she had no need to be speedy to get her food.

But it's the tiny bones in Dippy's inner ear that can give us a clue as to what she sounded like.

These little bones are basically the same shape as that of the dinosaur's closest relatives, birds.

The range of sounds a bird hears is related to its size.

A small bird makes and hears high-pitched sounds, whereas large birds communicate with low-pitched sounds.

So huge Dippy, with her inner-ear bones shaped like those of a bird, could probably hear very low-pitched frequencies of sound.

And she could probably make them too.

[ Low roaring ] [ Chuckles ] ♪♪ [ Low roaring ] We know that elephants today can communicate using infrasound, sound with frequencies so low they're below human hearing.

And those sounds travel through the ground sometimes for many miles and are detected by elephants through their large, flat, sensitive feet.

[ Thump ] Dippy too had large, flat feet.

So maybe the giant dinosaurs communicated with one another in much the same way, as well as by bellowing.

Her long tail would have helped to balance her long, heavy neck, but why was her neck so long?

♪♪ The most likely explanation seems to be that it helped her to reach leaves in all sorts of difficult places.

But in order to reach the highest, most succulent leaves in the forest, it seems likely that Dippy would have reared up on her hind legs.

Come on Dippy!

[ Smooches ] Breakfast, come on!

♪♪ [ Chuckles ] ♪♪ Oh, hello!

♪♪ [ Low roaring ] ♪♪ [ Low roaring ] ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ [ Door closes ] ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ London's Natural History Museum is full of wonders.

It's a place where we can get a vivid idea of the great variety of life that inhabits our planet, both today and in the past, especially after a night like that!

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.

♪♪