The Mammal Hothouse Fossil Wonderlands: Nature's Hidden Treasures

Most fossils are just the hard bits that nature leaves behind,

shells like these.

The other parts of the organism, the soft part if you like,

feathers, guts and many kinds of organisms that are soft-bodied,

leave no trace behind, except in a few very special places.

And it is to these places that we are going to

travel in search of windows into the past.

So far in this series we've been 8000 feet up in the Rocky Mountains to discover the fossilised

remains of the earliest complex life in the seas.

And travelled to China to see the newly discovered feathered dinosaurs

that are revolutionising our understanding of the origin of birds.

Now in this final episode, I'm heading to the heart of Europe

in search of a lost world from 50 million years ago.

This site in central Germany opens a window back in time

to a strange, yet oddly familiar world.

A site of special preservation

that demands unorthodox techniques of excavation.

And...

reveals the extraordinary story of the early mammals.

The area behind me was once a huge lake in the middle

of a rainforest, through which wondered little horses,

not much bigger than a cat, early predators,

relatives of the living hedgehogs

and maybe even our own earliest ancestor.

65 million years ago, the dinosaurs disappeared from the world forever.

But it wasn't a simple tale of the takeover by mammals,

it was complicated and interesting.

And to discover details to look into this early world of mammals and birds,

we have to come to this pit of Messel, in Germany.

The former quarry at Messel is one of the most remarkable fossil sites in the world,

an entire ecosystem trapped in time

with unparallel perfection of preservation.

Most famous for its fossil mammals, many of them still covered in fur.

Alongside them have been found the insects,

plants and fish that many of them ate.

And the reptiles and amphibians they sometimes competed with for food.

As well as the birds and bats that flew above what was a lake now lost in time.

First mined in the 18th and 19th centuries for brown coal,

the rich oil shale later helped power the German industrial revolution.

But, despite tantalising reports of fossils,

intensive mining prevented any serious scientific excavation.

When the machinery fell silent in the 1970s,

the fossil hunters rushed in,

and many paleontological riches hidden within the oily rock were revealed.

This is the metal shale - it's black, very black.

It's black because it's absolutely full of organic material.

And the organic material, of course, is what gives rise to the

oil for which this was commercially exploited.

The rock is divided into terribly fine layers,

sometimes less than a millimetre,

and each one of those layers represents a season in a year called varves.

But of course the rock also is famous for its fossils, and

each one of these layers potentially could trap the remains of past life.

Its softness also means it's possible to cut out great slabs

of the shale rather like cutting up a giant chocolate brownie.

CHAINSAW WHIRRS

'With me, to explain the process is Dr Stephan Schaal, the site's director.'

So they're taking the blocks out for today?

Right, we are taking one, two blocks,

one or two metres thick, er, with a chain saw and try to, to bring

them up to the hill and cut them layer by layer looking for fossils.

So that's all day's work from these two blocks here?

This is, er, three or four blocks per day, yes.

All together more than 100,000 fossils have been unearthed from the Messel pit.

And up to several thousand more are discovered every digging season.

Most are like this small fish, beautiful in their own right,

though so numerous, their to science is not now newsworthy.

But, once in a while new treasure is unearthed that has the potential to rewrite history.

Such as the claims for Messel's most famous fossil mammal.

I wonder what's in here.

LAUGHTER

Oh!

This is the best fossil and rarest fossil of bird life.

Yeah.

-Ever seen from Messel.

-Yeah, yeah.

In 2009, after 26 years of being hidden from the world, an anonymous seller parted with

the fossil known as Ida, for 1 million.

Her skeleton is brilliantly preserved,

possessing not just fossilised fur but even her last meal.

The buyers, the Natural History Museum in Oslo,

thought they'd spotted something that had been missed before -

clear evidence of an advanced primate characteristic, an opposable thumb.

'The discovery was claimed as revolutionary and it was

'proposed that Ida was our oldest known ancestor, a missing link.

'Dr Sandra Engels shows me two perfect replicas -

'one for each side of Ida's body.'

So both belong to the same individual

but split in half.

And in contrast to the other one, you can see the hands

and the feet with opposable thumbs.

-On both hands and feet?

-On both hands and feet.

-That's the sticky up one here.

-This is true.

You can see it very good on this foot here.

And by this you can directly see it as a primate.

And since it is so complete, one of the most complete

primates in the world, er,

it got very famous of course.

Well, we can see its fur

and we can see quite a lot about how the animal lived.

Yes, typical for a primate is it has a bony ring around the eye socket,

and we can see that the eyes look, as we call it rostrally,

so it looks in front of it, as typical for primates...

-Yes.

-..which is important for 3D vision.

And these have pretty large eyes,

so is that an indication they were nocturnal?

Yes, it is.

It is a nocturnal animal.

Er, is this a broken bone?

Yes, er, it's a broken wrist bone, but, erm,

we can also see that it healed again.

Erm, it happens often that primates fall off trees

and break their wrist bones or legs.

But what we can probably say for sure is that this primate,

this perfect primate, fell off a tree that happened to be

hanging over the water, so that it would fall down...

-Sometime, sometime this happened.

-..into that preservation layer.

This is why we have her now, this is true.

Ida is definitely a primate,

but whether she's our ancestor is still a matter of debate.

'But rather than get caught up in arguments about evolution.

'Dr Engels would like science to focus on Ida herself,

'and the beautiful way she has been preserved.'

It still is not clear where

Ida or this whole group of early primate belongs to,

but I think now it's time to look at the completeness of the specimen

and to analyse it in detail rather than being

concerned about its evolution or where it belongs to in detail.

'Produced from a micro CT scan is a computer model of Ida's skull.

'It allows us to dissect her virtually,

'and see previously hidden parts of her anatomy.'

So you can see, here, the 3D surface model of all teeth.

Each tooth takes about five days for one tooth in this case.

That's an awful lot of work...

-Yes, it is.

-..in that jaw.

So this is of course only done for very unique fossils as Darwinius.

So, er, now you've reconstructed the teeth, what's the next stage, you

see how the teeth actually work together?

We arranged the teeth in a functional way,

so what we do, I can show you the newest results...

-Oh!

-I can present to you.

And we have a special software programme

and it can calculate on the basis of the surface of the teeth

how they operated and worked together.

So they're like a piece of machinery really for processing food?

Yes, we let Ida chew again.

We know when we look at the morphology at the teeth that it ate probably leaves, fruit, seeds.

Er, so not ideally suited to being, for example, a carnivore?

Not at all.

Sometimes you can learn still more about fossils by studying

their modern counterparts.

'At Battersea Children's Zoo, Anita Halligan cares for creatures

'bear a noticeable similarity to Ida.'

Of course, not everything is preserved as a fossil.

If you want to understand more about extinct animals,

sometimes the best way is to come and look at their living relatives.

In the wild or even in a zoo.

Pst, pst, come on guys.

-One of the things you notice is their wet noses.

-Yes.

Well of course one of the things that would never

preserve in the fossil record is the wetness of a nose.

No, it would be very difficult.

But I guess the, the characters of the feet and the hands would

-preserve because they're, they're visible in the bones.

-Yeah.

And what is it about the, the hands of these animals?

They've got five, er, fingers, very similar to our hands, erm,

but they don't have an opposable thumb, erm,

and they have nails rather than claws.

Er, but on their, on their feet they have a, a large big toe,

erm, which is opposable which helps them to climb.

Well certainly those kinds of things could infer

something about the arboreal habits, for example?

Definitely, definitely.

'Although these lemurs have evolved to become omnivores, their diet

'is still largely the same as Ida's, eating mostly leaves and fruit.'

So I notice they take the food mostly directly from

our hands to their mouth, rather than taking it in their hands

and manipulating it,

in what we might think of as the typical monkey fashion.

Yes, they prefer to take things directly, erm,

with their mouth rather than holding it in their hand.

And a lot of these primates have very good sight

-and very sensitive hearing.

-Mm-hm.

Er, and perhaps, I don't know how sensitive the nose is as well?

Smell is very important for lemurs, it's how they mark their territory.

-So they will use their smell.

-To deter other males?

-To deter, yeah.

They can also do a stare as well, erm, which, er...

-I can think of one or two human males who do exactly the same.

-Yeah.

So now we have an image of Ida, but what about the climate and

ecosystem in which she lived, with whom did she share the Messel world?

The Messel site has revealed all sorts of other remarkably preserved fossils which help us

piece together the flora and fauna from 50 million years ago.

'The fossil flora is housed under the care of Dr Volker Wilde.'

It's all here. So we've got a vast collection here?

Yes, er, for more than 30,000 individual specimens from Messel

-and...

-From Messel alone?

-Yeah.

-And, er, how many species represented that you know about anyway?

-Far more than 200.

-So it might outnumber all, well it does outnumber all the mammals and reptiles...

-Yes.

-..put together.

-Yes, definitely.

Now we, we must look at some of these plants and...

-Yes.

-I think maybe a flower because, you know in poetry...

-Yes.

-..in every other way a flower is the definition of what doesn't last.

OK, so all you can see at the moment is black on black,

under glycerine to stop decay,

but if I tilt the light just in the right way, can you see?

It's a fossil flower.

And, er, the pollen grains are preserved in situ which is

extremely rare in the fossil record.

This amazingly well preserved flower is an ancient relative of the water lily.

Many other flowering plants, angiosperms,

flourished in the Messel period.

Flowering plants of course are arguably the most important organisms

-on the surface of the land today.

-Yes, and in Messel times, er,

you have to imagine a situation which is quite similar to today.

The diversity of angiosperms was similar to the diversity of flowering plants today.

-That's, it's one example where plants win over animals.

-That's it.

-Even though the animals tend to be cuddly.

-Yes.

This anatomy, er...

'These rare fossilised records of plant life suggest'

that the average temperature was well above 20 degrees Centigrade.

And the water lily isn't the only specimen which is surprisingly familiar.

I can recognise that, that's a bean pod.

Yeah. That's it.

Erm, and, er, it, well it looks like a bean pod.

-Yes, they do.

-And I think I could probably say that is a bean pod.

-It is, definitely.

-Er, and of course the bean family

-is enormously widespread today, isn't it?

-Yeah.

Well this is an extinct bean,

so I suppose might one might refer to it as a "has bean".

Wherever you find plants you normally find insects.

And another fossil takes us into the insect world that surrounded Ida.

Dr Sonja Wedmann studies another fossil which has modern descendants.

-Hello.

-Hello, Richard.

So this is the home of the fossil insects?

Yes, it is.

And, well I can see...

there's a thin little outline,

as I go back I can see the body expanding.

So what sort of insect is it?

Yeah, it's a leaf insect, it, it's the only one worldwide,

it's, it's a really amazing.

-So this IS the fossil record of the leaf insects?

-Yes.

-And you have pet ones?

-Yes, I have.

-So we can have a look?

-Yes.

They're hiding very well.

This is a, a young leaf insect.

You, you don't have to be an expert entomologist to see that

-fossil is very similar to this...

-Yes!

And look how it's rocking. Is that a fo...

Er, does that have a purpose, do you think?

It's part of their camouflage, they move like a leaf moving in,

in the wind and that they are camouflaged.

And of course the wonderful thing about these is today they're found

in South East Asia so we, we have another example, yet another example

in Messel of something that today has their relatives scattered all

over the world, erm, particularly in the Americas and Africa.

Er, but in Eocene times here they were in Germany.

If you want to get a visual impression of Messel

you could do worse than coming here, in deepest Berkshire, to, er, the living rainforest.

Er, here are a, a whole range of tropical trees

and animals live together in glorious profusion.

The world of Messel was a strange mixture, in part familiar, in part unfamiliar.

It was undoubtedly a rainforest and like rainforests today there

were large reptiles living in the trees and on the ground.

There were also a variety of birds.

Some of them were large ground-dwelling predators.

And there were mammals that were related to familiar species today, but they were different,

often they were small compared with their living relatives.

It was a greenhouse earth.

Carbon dioxide levels were higher.

There were probably no polar icecaps.

As a whole it as known as the Eocene Thermal Maximum.

Amid the plants and insects of this warm and humid rainforest,

Ida certainly wasn't the only mammal forging a niche for herself.

30 minutes north of the Messel Pit, is a museum that shows very

clearly how over the last 65 million years mammals have evolved to fill

almost every ecological vacancy left by the extinction of the dinosaurs.

But some of the early mammals who shared Ida's ecosystem,

whilst perhaps recognisable,

looked very different from those that roam the earth today.

One of the very best examples of this strange combination

of similarity and dissimilarity, is a mammal that has helped shape the course of civilisation.

-And this is one of the so-called...

-The horse.

In here is one of the primitive small horses.

Oh, that is absolutely beautiful.

-It's, er...

-It's one of these ones that's been completely separated from the oil shale.

The preparation is very nicely done, you can see every detail.

This is Propalaeotherium sometimes known as the Dawn Horse.

Standing at the same height as a mid-sized dog,

it's the creature from which our modern horse ultimately descended,

as Dr Sandra Engels explains.

So what about diet?

What can we tell from this specimen about diet?

You can see that they have teeth that are suited for leaves,

-but they also have blunt cusps that crush, yes...

-Like this?

And we also have gut content and when you look at it under

a microscope you can find particles of leaves or seeds inside.

But it's not like the living horses because it's eating leaves and nuts if it can find them.

-Yeah.

-So this started out, the horse started out more like say

a living deer which mostly browses in their habits.

-Something like this.

-And then moved into the grasslands later on.

As we know from Messel, it was, er, a rainforest.

This Dawn Horse lived in dense rainforests

15 million years before wide grasslands had developed.

Early horse species had yet to evolve the prominent physical characteristic

which many of us assume to be the defining feature of a horse.

The single hoof.

It seems to me that we've got rather a large number of toes

-compared with the living horse.

-Yes, they have four digits at the front

and three toes at their back legs.

That the third digit, the middle digit is already pronounced here.

And so this is a many-toed horse,

-but it's already showing horsiness...

-That is true.

..by that enlarged digit.

As the environment changed,

this third toe would evolve into the hoof of the modern horse.

Here in the Royal Veterinary College north of London,

horses are diagnosed and treated for all kinds of ailments under

the watchful eye of Dr Renate Weller.

This gives us a perfect opportunity to get down to the details of horse anatomy.

So you're looking at one particular foot of this particular horse?

-Yes.

-Because there's something wrong with it?

Indeed, and so we have many, many parts in there that can go

wrong, bones, joint, er, several ligaments, a tendon running

on the back of the horse's leg and into the foot, and this allows us

to evaluate all of them and then choose appropriate treatment.

By using the latest technology,

we can see how far the modern horse has evolved since his

diminutive relative scampered through the rainforests of Messel.

This is our MRI scan of the foot and of course one toe.

Er, absolutely which makes it actually easier to look at it

if you only have one toe.

When you look very carefully

we can see the tendon has ruptured er, some of its fibres,

so this is a very common injury we see in

horses and, well one of the reasons is because the way it has evolved.

But why one toe compared with our little several digited Dawn Horse?

Well, one is much more stable, it doesn't have that splay effect,

it also gives the horse the opportunity to have a very light foot.

And so, er, speed and endurance were part of the story?

Yes, the horse is, is an amazing creature.

The evolution of the horse's hoof is almost unique among grazing mammals.

For the horse is both sprinter and long distance runner.

But humans of course have capitalised on that speed part...

-Yeah.

-..and changed the horse in certain ways.

If you look at, at, at this, er, section, er,

-that's of, of a horse's, er, leg, this, this...

-So bred for length.

This is bred for length, er, can I borrow your finger.

Then we have, you have a relatively tiddly, er, metacarpals

whereas in a horse, this is very long.

We have the toe bones which start here, er, corresponding to this.

The next bone is here, corresponding to this one

and then the final bone with your fingernail corresponding to

that horned capsule that surrounds the horse's foot.

So that's my, my hoof...

-That's your hoof... Absolutely.

-..in a way.

The story of the horse demonstrates the Mammalian ability to adapt to changing ecosystems.

So when the Messel rainforest eventually gave way to

grasslands, the horse changed with it.

And side by side we can really appreciate just how far

they've come over the past 50 million years.

The sheer number of extraordinary fossils through which

we can bring to life the Messel world,

means it's all too easy to take them for granted.

Yet each one is actually the product of painstaking conservation skills.

These shales, they dry up very, very quickly.

This is a, a bowfin fish coming out here and the, the specimen

has dried out and is now very, very difficult to conserve.

Fortunately in this World Heritage Site,

techniques are available which make these specimens permanent

and save their scientific information for future generations.

As soon as a new find is made it is quickly brought from the pit

to this storeroom just a few minutes away.

Here, these treasures of Messel are kept sealed until

they are ready to be removed from the oil shale that encases them.

Once exposed, the fossils must be kept wet at all times to stop the oil shale from drying out.

So the, er, specimen has come out of storage...

'Dr Krister Smith, of the Senckenberg Museum,

'takes me through this delicate process.'

And a very long process it is.

Of course it's not like the preparation I've done because it's under water.

Absolutely.

A specimen must be kept moist at all times,

the oil shale here has a water content of about 40%

and if left to dry out, the entire fossil will crumble away.

And the matrix, the oil shale itself is being

scraped off little by little to expose the fossil.

So he's very carefully removing flake by flake every little

bit of mineral in there.

And for a big specimen this can take days?

-Months.

-Months.

This technique is perfect for preserving the fossils of Messel.

But perhaps somewhat surprisingly it relies on a bit of British

ingenuity, first set out in 1950 by Harry Toombs

at the Natural History Museum.

Toombs had been using acids to extract fish fossils from various soft rocks.

But deprived of the rock they were held by, the bones could fall apart.

To keep their structural integrity,

Toombs hit upon the idea of stripping out one

side of the rock and then replacing it with a plastic resin.

So the specimen here is still a little bit moist

and what we need to do is first dry the surface

so that the epoxy can adhere.

That's the kind of, er, technical...

equipment I can cope with quite... confidently.

I guess you gotta make sure you don't get air bubbles

trapped in there because that would be both unsightly

-and could obscure some scientifically important detail.

-Absolutely.

Once one side of the fossil is set in dried epoxy,

the clay is delicately removed

and the process can then be repeated for the other side of the fossil.

And this is the finished result.

A fossil bowfin removed from its rocky matrix after 47 million years.

It's a wonderful way of studying extinct life.

It might be hard to realise just how unusual this

level of preservation is.

A different extraction process at the Natural History Museum in London makes it clear.

I take a journey into the vaults.

So this is the scruffy part of the Natural History Museum that people don't usually get to see.

We're off to see a special kind of washing machine.

It's operated by the museum's mammal man, Dr Jerry Hooker.

Ah, Jerry this is where you hide out?

That's right, it's a very special washing machine, it's a

clay washing machine, and it's for washing this sort of stuff.

-Lumps of mud?

-That's right and we wash the mud away and we find little tiny fossils.

-So I'll load it in.

-Take it away.

Right, if I give you that.

The lid goes down.

Go and turn the tap on.

And...

Here we are in the inner sanctum.

Yes, this is where the...

'In Jerry's office, I see the next stage of the painstaking process.'

So this is a typical residue, erm,

after the clay machine has washed the mud away.

Erm, it's, we haven't got there yet, er,

what you see there is, is almost all shell,

and there will be little tiny teeth and bones in there as well.

But it takes forever to actually, er, pick them out,

so we concentrate it further, and you can do that with acetic acid.

-So you dissolve the shell?

-We detach the shells, yep.

-But doesn't touch the teeth, or bones?

-That's right.

-Then you're left with something like this?

-That's exactly what's happened,

It's the same sample, er, and that's been treated and that hasn't.

Occasionally if you're really lucky you, you get jaws...

-A whole jaw, well I can see...

-A whole jaw

and this is a jaw of a rodent, so.

-So you must have been absolutely thrilled when that turned up?

-Absolutely.

Well they're very hard one, they're beautiful three dimensions,

but of course it's not quite the same as having...

-It's not the same as having...

-..all the fur and the gut contents.

..the whole animal, that's right. You, you need both.

'Finding mammal fossils in the UK is the paleontological

'equivalent of finding a needle in a haystack.

'A tooth in a clay bed perhaps.

'And helps to remind us how detailed and miraculous the Messel discoveries are.'

Messel rodents, for example, can be found with three different designs.

One was built for speed with long back legs.

One elaborately protected with bristles.

And one with an unlikely combination of both.

The mammals of the Eocene period were already beginning to

display the traits that would help them surpass many competitors.

Most importantly they were rapidly adapting to their surroundings.

There is one familiar mammal that shows just how similar animals

could evolve into subtly different species, all able to occupy

and exploit a different niche within the same ancient environment.

-Oh!

-They are also the most abundant mammals found at Messel.

Bats.

'Dr Jorg Habersetzer shows me his collection.'

So here you have the smallest species, this is, er,

one extinct family represented by two different species.

This one was flying very close to the surface

of the former Messel Lake.

And we have a second family, and...

And is that also a low flyer?

No, this er, er, bat was flying in a middle corridor,

that means in-between trees and in a flight altitude of,

let us say eight to 15 metres.

And, finally, here these are already very highly sophisticated

specialist by means of echolocation.

So that's the same echolocation that living bats use?

-Yes.

-And is that actually a member of a living group?

This is also true.

When you, erm, when you unfold, er, all this skeletal elements here...

So that's like an umbrella that's spread out?

Yeah, it is a bat with a very narrow slender wing, it is

-a typical morphology of a rapid and high flying.

-A high flyer.

Every bat species living today can trace a line back to the

characteristic wing forms and echolocation

present in the seven species found in the Messel Pit.

And just from a common sense point of view, people might think a bat

is an extraordinarily specialised mammal and yet here we have bats...

-Yeah.

-..in Messel, whereas some of the other perhaps more familiar mammals, predators...

-Yeah.

-..large herbivores have yet to appear.

So, if we're got seven species of bats

and we've got a whole ecology from low, middle and high altitude.

-Yeah.

-Obviously there must have been a lot of previous bat evolution.

-Yes.

-About which we know nothing.

By the time of the Eocene, these bats had already become finely-tuned specialists.

Flying at three distinctly different heights they would have been

able to find food where other competing animals could not.

But however well adapted these bats, Ida and other mammals were

they were not without competitors.

Some people might think that the demise of the dinosaurs was

also the decline of the reptiles.

Nothing could be further from the truth.

The Messel fauna proves the reptiles were evolving as vigorously

alongside the early mammals as ever in their history.

I've come to talk reptiles with Dr Krister Smith.

-Richard.

-Lovely to see you.

-And you as well.

And we're gonna talk reptiles?

We are. I have just the specimen to show you.

Fantastic!

It's a snake and more besides.

Indeed, this on a superficial view looks to be a lovely specimen

of a snake, it also happens to be a yet un-described species of snake.

-So it doesn't have a name yet?

-It doesn't even have a name.

And if you look more closely as you've just done,

you'll notice that there is something more inside it.

I, er, er, it's sort of lizard like?

It is in fact a lizard which is found inside the...belly of the snake.

Now when the specimen is first prepared, you will also see

this black content inside the belly of the lizard.

OK, I can see it more as a black smudge here.

That's right.

And the paleo-entomologists tells us that this is a beetle

inside the belly of the lizard, inside the belly of the snake.

So what we have here is a one-specimen food chain?

That's exactly what it is, something like a Russian doll, if you will.

The poor beetles, they've been food ever since they evolved.

HE LAUGHS

Then as now, insects were a rich source of nutrition,

high in protein for reptiles, mammals and birds.

The extraordinary thing about Messel is that it contains not just

the large fossils like mammals and birds and a host of reptiles

but also the fossils of small things, particularly insects.

And in the tropical rainforests of Messel they came in all shapes and sizes.

So, Sonja, what have we got first?

Yeah, we have here a nice big cockroach. Yeah, it's really big.

Almost five centimetres long.

-So cockroaches did then what they do now...

-Yes.

..which is scuttle along on the forest floor

-eating almost anything that's edible?

-Exactly.

And they're the great survivors, they've already been around

-for 200 million years or something like that...

-Yes.

-..by the time they arrive at Messel.

-Yes.

Moving...delicately on.

These are so-called giant ants.

-They are indeed. And, er, aren't they called something like...?

-Yes.

-That's right.

Which obviously means the titanic ant,

-and very special indeed and, may I pick it up?

-If you want.

There we are, we can see through this slab to see these gigantic,

-and these are queens, are they?

-Yes, they are.

-So this is the big flying generation for these ants.

Erm, and in fact the, this is the smaller species,

we have two species in Messel of these ex...extinct giant ants.

-They get bigger?

-Yes.

And perhaps the most surprising thing of all...

-This is a jewel beetle.

-A jewel, oh my goodness, yes.

We can see why a jewel beetle. Because it's got iridescence.

And when you think that that is caused by structures

that are, er, microns across, thousandths of a millimetre across,

-that just testifies to the extraordinary preservation at Messel.

-Yeah, that's really true.

And the supreme quality of preservation doesn't end there.

These insects even retain fossil colour, and new research is

illuminating the secrets of such preservation in surprising detail.

Working at the forefront of fossil science, studying colour and how

it's preserved, is Dr Maria McNamara from the University of Cork.

She's trying to understand the role and evolution of colour in nature.

And she's devised an innovative method of recreating the past.

Baking.

This is what the beetles look like before cooking.

I've seen a beautiful fossil beetle in Messel which shows colour,

and this is a living relative, a jewel beetle, so can

I believe my eyes with what I saw on the Messel fossil, is it real?

That's a really good question because, erm, it's possible

when you look at the fossils that the colour you see could have been

generated during the fossilisation process, an artefact, and they

may not be related to the original colour of the insect at all.

Erm, however when we look at the fossil beetles using powerful

electro-microscopes, we find the exact same evidence of colour

that we see in these modern beetles.

You see these modern beetles, the colour we see, it's not made by pigments,

it's made by very fine layers.

And these layers act like mirrors, so they reflect light, erm,

and they actually reflect light in such a way that we get a very pure, a very bright colour.

But nonetheless time has done something to the colours?

Exactly, the, the, the interesting twist in the story is, are the

colours we see preserved today, the original colours of these insects?

-Well let's have a look.

-OK.

'By using high pressure, high temperature ovens,

'Maria can replicate the process of millions of years of fossilisation.

'And reconstruct the original colour of the Messel fossils.'

We have one of these modern jewel beetles that has been in the oven for one hour.

I can see that that's, er, much bluer,

a brighter blue compared with the original one.

It is, so the colour is changing, and here's what the colour

looks like after it's been in the oven for 24 hours.

-And it's gone quite indigo in colour?

-Yes.

So what's going on is we have a very clear progressive colour change.

Our green colours are being blue shifted,

gradually turning blue, indigo. Eventually, if you were to leave it in for several days,

it would turn black, the colour would be destroyed.

But that's also a shift in time isn't it, this is a, a, a...

We're going back in time and as the insects get buried, the heat increases.

Exactly, the deeper you go, the hotter it gets.

So we know the fossils have been buried,

we know they have been heated up, so now

we can actually start to quantify how much the colour has changed.

So when we look at a, a Messel fossil, which is

sort of up this end of the colour, we know that

when it was alive, it had the same colour as our living jewel beetle?

Exactly. To work, to backtrack and get back to the original colours,

we have to work in this direction.

So regardless of how much the colour has changed,

we know for a fact that they had these wonderful metallic

iridescent colours, and they were probably using them

for the same purpose that the modern relatives use them for.

-Such as?

-Such as, erm, well in this case, we would say sexual signalling,

we'd say to attract mates.

But in other cases these metallic colours can actually be used

to, erm, to deter predators, to scare off predators.

So for once you could say that cooking the results is

-the right thing to do?

-That's it.

It's an unusual thought that the same technique that insects

use today to repel mammal predators

date back 50 million years or more into the past.

Yet none of these insights would be possible were it not for the

ancient Messel Lake that became a watery grave for so many animals.

The lake was formed during a period of heavy volcanic activity.

'And as Dr Stephan Schaal tells me,

'Eocene Germany was a particularly volatile place.'

And the volcanic rock is implicated in the formation of this great hole.

-Right.

-What happened?

The hot magma came up and got in contact with the ground water,

and the, er, er, there followed a lot of explosions and the

result was a big hole, an enormous hole, a natural catastrophe it was.

And that was followed by the hole being filled which made

-the lake where our animals lived and died?

-Yes.

We've still got a well here, have we?

'In 2001...

'the team at the pit drilled down half a kilometre into the earth's crust,

'to confirm the theory that the lake was created by volcanic activity.'

-And we use this...hole.

-Ah!

The borehole still remains and pumps out ancient Messel water.

-Let's, let's, let's see what it tastes like?

-Yeah.

If I can get near enough.

Not terribly nice.

No. It tastes of iron, iron and sulphur.

And the sulphur is the last little gasp of that volcanic eruption.

And the age of this water may be around 14,000 years.

So, what caused the presence of such a wealth of fossils

at the bottom of this ancient lake?

One theory which accounts for the killing of the animals at Messel

is connected with the volcanic activity.

Although the active volcano had ceased,

from time to time belches of carbon dioxide were released,

a heavy colourless gas that lay over the Messel Lake like a blanket.

Any bat that dipped down into would be suffocated

and fall into the water and down to be preserved in the mud.

The same applied to animals perhaps drinking at the edge of the lake.

These were periodic, so that through time generation of animals

were sampled in an irregular way to be preserved.

There is a modern analogy for this theory.

In 1986, a huge eruption of carbon dioxide from the bottom of Lake Nyos in Cameroon

crept silently through surrounding towns and villages,

killing 1700 people and 3500 livestock.

But there is an alternative killing theory.

'It's put forward by former Director of the Messel Pit.

'Wighart Von Konigswald.'

Erm, turtles, they've obviously...

'He believes one clue is the number of fossils

'preserved in the act of mating.'

Er, the main question is how did these animals come to, er, to die?

It was not a catastrophe. This occurred again and again and again.

-A regularity, then?

-A regularity.

Let's, erm, er, we've got a, a, a lovely fossil turtle here,

let's cast some light on the subject.

So this is... we're looking at fossil sex here?

We look at fossil sex.

I do not know exactly which one is male and which one is female.

And turtles are likely to have mated at one particular time of year.

So this was a seasonal effect?

Yeah, a signal for a season.

But this is not only specimen,

we have seven or eight specimens of the turtles in mating position.

This is an indicator that we have not a volcanic gas eruption

which has no reason to be related to seasons,

but there's something else.

Von Konigswald thinks an annual bloom of cyanobacteria -

blue/green algae - would have released poisons that formed a deadly scum on the lake surface.

When these cells die, they produce gas inside the cell,

so the gas floats up to the surface of the water body,

and form a foam called a scum.

-A poisonous foam?

-And this is highly poisonous.

If you have animals drinking from that water

they will die immediately.

50 million years later it's a difficult theory to prove, but research continues.

The Messel Pit has provided palaeontologists with

an unrivalled insight, not just into early mammals,

but the entire ecosystem within which they evolved.

Yet perhaps surprisingly this legacy was almost lost.

And I gather were it not for the actions of some of you

and some of your colleagues, there might be no pit at all here?

That is possible, yes.

In the 1970s, just as the true significance of the site was being realised,

the local government tried to sell off this great pit for landfill.

'Dr Stephan Schaal was at the forefront of a 20-year struggle that came to an end

'when the pit was awarded the status of a World Heritage site.'

So how did you feel after nearly 20 years of campaigning

when suddenly you'd won a Unesco site?

Er, it was a wonderful feeling indeed, if you're fighting for

something for 10, 20 years and then suddenly from one day to the other

that you have the decision, you have to read it two times to believe it.

It was a great feeling and it lasts till today.

-And so now, well, I'm happy to say this is safe, as safe can possibly be.

-Yes.

Their efforts saved a unique window into an ancient time,

and possibly the origin of the human line.

The Messel menu almost brings the bill of fare up to date.

What have we got for Messel munchies, practically a modern smorgasbord.

Er, remember the giant ants in Messel,

well, I guess this is their modern equivalent.

They were food for the...

mammals at Messel, but, and they can still be food, but they are a bit dry.

Well, I think I'm gonna tuck into some grub or in this case actually some caterpillar.

So now we've got pollinators.

Oh, goodness me.

Erm, well, I mean if I'm honest it tastes just like wood.

Oh! Well, main course is...

Of course we've now got a variety. This is lamb.

Heart possibly.

Hm. Quite succulent.

And, of course, the ubiquitous pig that formed so much of modern society's diet.

And all washed down with the, the essence of mammal milk,

well this could be horse, it could be cow, it could be goat.

Ah!

And perhaps afterwards, well maybe some fruit, because of course

the flowering plants and fruits have evolved by then.

But what's missing?

Bread, the staff of life,

because those kinds of cereals have not yet evolved.

So this particular slice of life had to await the future.

In this series, we have sought out and revealed the secrets of three long vanished worlds.

Wow!

Each represents a key moment in the narrative of the deep past.

And reveals new insights into the design of life and the story of evolution.

There may be a vision of evolution as a kind of steady progression,

almost like a train that moves inexorably from station to station,

perhaps reaching a junction where two branches diverge into different directions.

We know now that evolution happened in bursts of creativity.

We know that small worm-like animals could evolve to walk on land.

We know that dinosaurs acquired feathers that became

capable of flight and produced birds.

We know that mammals no bigger than a mouse could evolve into a mammoth.

Transmutation is all.

We've seen life trapped in stone, we've seen events

trapped in time, but evolution can only work with what it's given,

which is why there will never be a mermaid nor sadly an angel.