Woolly Mammoth: Secrets from the Ice

Imagine an elephant, but with tusks at least twice the size

of those borne by an elephant living today.

Imagine an elephant, but covered in a thick shaggy coat of hair,

some of those hairs over a metre in length.

Imagine an elephant which lived not in the warmth of the tropics,

but in the ice and snow of the north.

The woolly mammoth.

These majestic titans ruled Europe and Asia

long before our own ancestors fell under their spell.

Extinct for thousands of years, they are iconic, yet mysterious.

Climate change means that the frozen north is melting faster than ever before.

Prehistoric carcasses are emerging and, from them,

we can unlock the secrets of these long-lost beasts.

Using the latest technology,

we can now answer questions about the mammoth which have long-puzzled scientists.

This is, in essence, virtual time travel.

That's starting to sound a little bit like Jurassic Park!

We're able to trace their evolution, revealing their adaptations

to one of the harshest places on the planet.

This is amazing!

And with every new find, we take a step closer

to answering the biggest question of all -

why did these magnificent animals suddenly go extinct?

-I want to show you.

-Oh, fantastic. That's brilliant.

-I want to share with you.

Siberia.

Here, the temperature hovers around minus 40 for months on end.

Few animals can survive here.

A hundred thousand years ago, it was a different story.

THUNDER RUMBLES

This giant swathe of Eurasia was home to vast herds of woolly mammoths.

Perfectly adapted to the extremes of the Arctic,

a tiny population survived on a remote island

until about 4,000 years ago.

But, on mainland Siberia,

they mysteriously died out at the end of the last Ice Age.

But we're left with a treasure trove of their remains,

locked in Siberia's layer of frozen ground...

..the permafrost.

As global warming raises the earth's temperature,

melting the permafrost faster than ever,

the secrets of the mammoth are finally emerging.

After centuries of collecting their remains,

we can paint a detailed picture of these long-lost beasts

far better than we can for any other extinct species.

We know that they lived for up to 60 years

and were perfectly built for life in the freezer.

But many of their adaptations have remained secret, until now.

And there's one big question, which remains unanswered.

What killed them off?

This is one of the most famous mammoth-finds of recent years.

She's called Lyuba, and she's a little baby mammoth,

probably just a month old.

She was found in 2007 and she is amazingly well preserved,

so that we have her skin, her soft tissues

and we even have the contents of her gut.

Lyuba has been radio carbon dated to 37,000 years old.

Found in the far northwest of Siberia,

she's considered to be the best-preserved mammoth ever discovered.

It's wonderful to get so close to this little baby mammoth

and see how beautifully preserved she is. You can see the texture of the skin.

You can see individual hair follicles there,

and there's even some fur preserved, some little patches of it.

And then on the surface of the skin as well, there are these peculiar blue discs,

which are part of a fungal infestation that happened after she died,

part of the burial environment that she was in.

And she's lost her tail,

that's about the only bit of her that isn't there.

It's thought that Lyuba died in a bog,

where she was first pickled by natural chemicals, and then quickly frozen.

Large specimens, like fully-grown mammoths,

usually deteriorate before this occurs.

In fact, any type of frozen carcass is incredibly rare.

Lyuba is one of a mere handful of frozen specimens ever discovered.

Isn't it peculiar to think that humans saw these alive.

I think that's quite a strange thought,

to know that there were people living here in Siberia

during the peak of the last Ice Age, and these animals would have been in their environment.

They would have been very familiar to them,

just as people living in Africa and southern Asia share their landscape with elephants.

Our relationship with mammoths dates back to the early days of modern humans in Europe.

Their herds clearly inspired cave art.

We've been transfixed by their majesty for thousands of years.

But, once extinct, mammoths became the source of myth and legend.

Their huge bones were thought by some to belong to a long-lost race of giants.

Others believed they belonged to a bizarre subterranean mole-like creature

that died when it came to the surface.

The name "mammoth" comes from an ancient Russian word, "mamont",

meaning "earth horn" used to describe the animal's tusks.

But it wasn't until 1728 that British scientist Sir Hans Sloane

spotted the similarities between Siberian remains and a group of modern specimens

that it was eventually realised that mammoths were a type of elephant.

Major differences were obvious in the mammoth remains -

huge tusks, increased musculature to carry the tusks, a shoulder hump.

the big question was how and why such an animal

came to live in the extremes of the northern hemisphere.

We now know that mammoths were a species created by,

and perfectly adapted to, the most extraordinary period in Earth's history

the Pleistocene, or Great Ice Age.

This two-and-a-half million-year cold snap changed the planet,

and transformed the mammoth into a titan

capable of thriving in the extremes of the Arctic Circle.

That change occurred in a blink of evolutionary time,

and was driven by a perfect storm of exceptional events on a planetary scale.

For millions of years,

Antarctica had been drifting southwards to its current position,

sending the southern hemisphere into a deep freeze.

And South America was charging northwards.

It crashed into North America,

and this altered the ocean currents and gave birth to the Gulf Stream.

And the knock-on effect of that was increased precipitation in the northern hemisphere,

which in lower latitudes fell as rain, and, in the north, as snow.

While these tectonic events were changing the face of the earth

and propelling it into an ice age, there were also changes occurring

on a celestial scale, producing dramatic fluctuations in the earth's climate.

The earth's distance from the sun changes over time.

Every 100,000 years, the earth is at its furthest position from the sun's warmth

and our planet enters a cold phase.

Then there's also variation in the tilt of the earth on its axis

and that happens over a cycle lasting 41,000 years,

and affects the degree of difference in the seasons.

Finally the earth also wobbles on its axis

on a cycle lasting about 23,000 years.

When all those planetary factors coincide, winter takes over,

with ice sheets covering 40% of the Northern Hemisphere.

To glimpse the extreme conditions that mammoths faced,

I'm visiting a remnant of one of those immense ice sheets.

This wall of ice marks the point two thirds of the way up

the Athabasca Glacier, which is about four miles in length

and feeds off the huge Columbia Icefield in Western Canada,

but even that would have been dwarfed by the huge ice sheets of the Pleistocene.

In places the ice would reach up to 13,000 feet thick.

These glaciers are really beautiful.

Really craggy. You look down into the crevasses and they're deep blue inside.

They're rivers of ice.

It's incredible to think that most of that would have been under ice,

with just perhaps a peak of the highest mountains popping out above the ice sheet.

This is amazing!

Wow! Oh!

The ice sheets locked in so much water that they created cloudless, blue skies.

At latitudes below the ice,

this provided perfect growing conditions for shrubs and grasses,

creating a vast grassland, known as the mammoth steppe.

The steppe proved to be a massive untapped food supply

for any animal able to adapt to eating its plants.

This newly available niche drove the mammoths

to evolve from their origins in the warmth of the southern hemisphere.

At London's Natural History Museum, Professor Adrian Lister

has traced those origins through his collection of bones,

tusks, and, in particular, teeth.

What we've got here is a lower jaw, or mandible, of a very early mammoth.

So here's the jawbone, and this is a kind of molar tooth

that is adapted for eating plant matter, as all elephants and mammoths do,

and, by counting the number of enamel ridges in this tooth -

this one's got about ten -

we get an idea of what kind of plant food these animals ate.

This one would suggest that this creature was eating the leaves of trees and shrubs,

quite soft vegetation.

Teeth like this show that mammoths

shared a common ancestor with living elephants about six million years ago.

Over the next three million years, mammoths separated into different species

as they moved north from their Southern African origins.

It was the early mammoths that grew truly huge,

some standing over four metres tall at the shoulder,

and weighing twice as much as an African bull elephant.

From about three million years ago,

we pick up the first remains of the mammoth line out of Africa, north of Africa.

As they moved through the Middle East and into Eurasia,

mammoths evolved very quickly.

Adapting to the cooling conditions,

their tails and ears shrank to conserve heat.

Woolly mammoths eventually ended up the same size as Asian elephants.

Just like elephants, they probably spent most of their day eating,

but the plants of the steppe

were far tougher than those available in the tropics.

Mammoths had four molar teeth.

To cope with the wear and tear caused by their new diet,

these molars evolved to have more ridges and higher crowns

than seen in their relatives.

And so we have fossils like this molar, from Siberia,

and that is just about as far as it got, that's the limit.

So you can see that there's about 26 of these enamel ridges.

They're very closely packed. This is an almost 100% grass eater,

which is a late Pleistocene woolly mammoth. This is from the last ice age.

As members of the elephant family,

it's believed that mammoths would have behaved in a very similar way to their modern relatives.

They would have lived in extended social groups,

females of all ages, young males and infants.

Now, remains from the Siberian permafrost

are revealing far more than just teeth and bones ever could.

The frozen baby Lyuba shows that mammoths possessed an unusual tool,

perfect for feeding on the steppe.

She's got this very particular shape to the end of her trunk,

which is quite different from modern-day elephants,

and it's designed to be able to delicately pull up

little tufts of newly-sprouted grass and shrubs.

Because Lyuba is so well-preserved,

new scientific techniques have enabled us to examine her internal organs,

revealing startling adaptations to the extremes of the Ice Age.

Recent CT scans show her kidneys are far larger than you'd expect in an animal of her size.

This type of oversized kidney is also seen in desert-adapted camels

suggesting that mammoths' internal structure was also changing

to cope with the dry conditions of the Mammoth Steppe,

where there was plenty of food, but little water.

Frozen carcasses like Lyuba are revered by scientists

as windows into the past.

She was found on the banks of the Uribei River,

on Siberia's Yamal Peninsula.

She was brought in from the cold by the French explorer Bernard Buigues.

He's hunted mammoth remains for over 20 years, amassing a huge collection

which he shares with scientists around the world.

Here we have approximately 400, 450 remains of different mammoths, yeah?

But, of course, not 450 full carcass.

But each bone can tell you the story of the animal

so we can say that, here, we store around 450 mammoth.

Bernard works closely with a large network of indigenous Arctic people.

They contact him when they stumble upon mammoth remains.

He now gets more calls than ever as the permafrost is melting

at an unprecedented rate, exposing potential new finds.

A brief window of fine weather bathes the Arctic

in round-the-clock sunlight each summer.

It's the perfect time for me to join him as he makes camp

and starts a new expedition following reports of a mammoth discovery.

If true, it will further our understanding of these Ice Age titans.

We're deep in the tundra here, about 200 miles north of any major town,

and it's beautiful sunny weather at the moment,

but it could turn at any point and the snow could return.

This is such a dynamic time.

Things are on the move, and things are being eroded as well.

The river banks are literally falling into the rivers as the water levels rise

and so it's precisely now that ancient remains start to come to light.

Bernard's a member of the International Mammoth Committee...

..a team which includes palaeontologists...

..geophysicists with ground-penetrating radar...

..and even an ex-KGB officer.

Professor Dan Fisher of Michigan University

is the world's leading mammoth tusk expert.

He visits the Arctic each year,

and, through analysing hundreds of tusks,

he's developed an unrivalled understanding of the mammoth populations that once roamed here.

So did tusks grow throughout the life of a mammoth?

Do they actually represent a record of an entire lifetime?

They do.

That's one of the, I mean just thinking of it

sort of aesthetically, it's almost magical,

but here these things are that do grow throughout life,

that are virtual diaries.

There are days represented, each day as a thin layer of dentine,

days, weeks, years are all recorded structurally

and in patterns of compositional variation

and of course they didn't do it for our benefit!

But what insights it gives us in the lives of these animals.

'Although each tusk is a valuable source of information,

'it's only when multiple finds are compared with each other,

'that Dan's able to construct an understanding

'of entire mammoth populations.'

I think it can seem as though you are stamp collecting,

that you're just collecting specimens for the sake of it,

but there's a real scientific value to them.

There is. The problem is not solved.

We've established that the data that we would need are available.

We've established the first few points that suggest a direction

and give some meaning to the patterns that we see.

'Understanding mammoths takes more

'than museum work and text books,

'it requires teams like the International Mammoth Committee

'to venture into the wilderness, working with locals

'and hunting for specimens, at times chasing nothing more than rumours.'

Bernard's just been on a reconnaissance mission,

so hopefully he should be able to corroborate whether there

is in fact a mammoth around here, or whether it's all wild tales.

DOG BARKS

Welcome back, welcome back.

So Bernard, how did it go?

Difficult to say, you know how fast things are changing.

-Yeah, yeah.

-So, some days ago it was under ice,

and today and tomorrow I don't know we'll see what will happen.

Have you been able to speak to anybody that's actually seen it?

No because it's a bit secret, yeah,

you know the one who knows about the mammoth, won't say to anybody and...

But I see that you are very impatient and I'm...

Yeah, yeah, I'm excited to get there.

Yeah, I am, I am, I'm also.

'Bernard has scant information to work with.

'During this hunt his team are hitchhiking

'with a Siberian gas company's private train network

'to visit the scene of a mammoth sighting.

'It's now flooded after the spring snow melt.'

You see the location is quite big, yeah?

It is a large lake. And do you think the mammoth is where

in relation to the lake thing, because it's a big lake.

It's difficult to know can be in the middle of the lake,

-can be on the side.

-I hope it's not in the middle of the lake.

Yeah, yeah, can be, can be.

'The team is trying to use ground penetrating radar

'to search for specimens underground.'

'Here they work for days in an effort to find

'one of the rarest of all prehistoric riches -

'a frozen carcass.

'Looking for ancient mammoth remains is unpredictable.

'It's a science, but an inexact science.

'This hunt concludes with a negative result.'

I am a little bit frustrated but,

just now I need to keep in mind how to organise the next step

for this mammoth because I will not let him,

let's say alone, yeah, we need to take care of him.

See what will happen during the summer.

Yeah.

LAUGHTER

'Each new specimen has the potential

'to deepen our understanding of mammoths.

'In many ways we actually know more about mammoths

'than we do about many living species,

'enabling us to recreate how they would have lived

'on the Siberian plains.'

'Much of that understanding has come from

'the recent advances in analysing mammoth tusks.'

I first met Dan Fisher out in the field in Siberia,

but now I've come to his place of work

at the University of Michigan's Museum of Natural History,

to find out what happens to the tusks which he brings back with him.

'It's the internal structure of a tusk which reveals

'a mammoth's true secrets.

'But the only way to see it is to break a tusk open.'

Dan, this is a beautiful tusk.

It seems like an almost sacrilegious thing to think of doing,

you know this has survived for thousands of years

-and we're going to cut it open.

-Well, I understand that,

but what if you found an incredible old manuscript and it was closed?

Would it be sacrilegious to open it and read it?

Would it be sacrilegious to learn from it?

Yes, in some sense, we are, you could say, violating the tusk.

But in another sense it's really capturing the story it has to tell.

Which tooth is it that forms the tusk?

The tusks of elephants and their relatives

are modified second incisors, so not our middle ones,

-but just lateral to that.

-The lateral incisors.

Can you tell if it's a left or a right?

Yes, this is a right tusk, based on the geometry of curvature,

is such that it's characteristic of what

we see on the right side of mammoth's faces.

So a right tusk. And do you know how old this animal might have

been at the time of death?

This was probably say about a 15-year-old.

That's a ballpark guess right now,

we'll find out after we cut the tusk.

-Yeah, so a teenage mammoth!

-Right.

'Dan needs a clean cut,

'so he builds a bespoke cradle for each tusk before slicing it open.'

All right.

'The largest mammoth tusks ever found

'weighed almost 120 kilograms each.

'Far more than an average adult man.

'Both male and female mammoths possessed large tusks,

'and it seems that the weight of carrying such huge objects

'required them to have larger neck and shoulder muscles

'than we see in modern elephants.

'The surface of tusks show microscopic scratches,

'possibly caused when mammoths used them

'to clear ice and snow while foraging for food.

MAMMOTHS TRUMPET

'And polished areas indicate they may have favoured

'one of their tusks for resting their trunks on.'

Well we've done it, now we've just got to open it up.

-Ooh.

-The moment we've waited for.

Can I do this Dan?

Yes, you certainly may. So just lift up and away.

SHE WHISPERS: Look at that!

-That's beautiful.

-It's gorgeous.

So, I can see a darker streak and a paler one and a darker one,

so is that a year in this animal's life?

That would be a year, yes.

The dark portions basically are winter,

and so the light and the dark together would make one year

and the next light and dark together would make the next year.

-So, this is a record of an ancient Winter.

-Right.

'The tusk is packed with information,

'but the patterns in it are hard to see until it's polished

'and viewed under ultra violet light.'

-Oh, wow.

-OK, now that is a lot better.

-That's fantastic. What a difference.

-Isn't it?

That's amazing, that's so much more detail than we could see.

-It's like you've put on magic glasses and you can see through it.

-Yeah, yeah.

'Like other teeth, tusks grow from the jaw outwards.

'Once highlighted, the growth bands are clearly visible,

'spreading from root to tip.

'Although this tusk shows about 15 years of growth,

'there are in fact hundreds of microscopic growth lines present.'

-We're seeing some really beautiful fine lines here.

-Yes.

So we can see successive winters and summers, winters and summers,

-Right.

-Winters.

-Right.

Now, in fact, the direction of time though is outside in, so the years.

It's the opposite of trees is the way to think of it.

In a tree you would think time goes this way

but in a tusk time goes this way.

And it is like looking at tree rings,

you know we have these kind of annual cycles in tree rings as well.

Except that tusks have weeks and days which trees don't have.

That's fantastic.

This is just incredible and very, very beautiful as well.

Under this ultraviolet light we can see this detail within the tusk

that is a thing of great beauty, but underneath that beauty,

inside that beauty, is this information

about this mammoth's life.

'Drilling out tiny amounts of ivory from daily growth lines

'allows Dan's team to analyse chemical isotopes

'laid down on that day, painting a prehistoric picture

'of the animal's life with a level of detail

'that's not possible for any other extinct species.

'Oxygen isotopes, from the water it drank,

'reveal where the mammoth roamed throughout its life.

'Nitrogen isotopes reveal where a mammoth was

'getting its protein from.

'We can even pinpoint exactly

'when an infant was weaned from its mother's milk.

'Carbon isotopes show the types and relative quantities of plants eaten.

'Thinner and darker growth lines

'indicate winters when less food was available,

'and in some cases, periods of starvation.

'Because the growth lines are so detailed,

'Dan can identify the point when, upon reaching sexual maturity,

'teenage male mammoths were cast out from their herds

'and left to find food for themselves.

'It's also possible to see that sexually mature males

'starved themselves every year, during the period known as musth,

'just as living elephants do.

'This sees them all consumed by the desire to find a mate.

'They fail to eat and their tusks show a period of decreased growth.

'The tusks also bear witness to traumatic events,

'including the most spectacular of all sights

'a battle between males competing for mating rights.

THEY TRUMPET

THEY GROWL

HE TRUMPETS

HE TRUMPETS

The study of mammoths is nothing new.

They were first described scientifically over 200 years ago.

But now new techniques in DNA analysis are being used to

decipher the mammoth genome.

'Here at America's Penn State University,

'geneticist Stephan Schuster runs a team

'of DNA specialists who are using cutting edge 21st century

'technology to analyse mammoth DNA.

'Their results are pushing our understanding of mammoths

'far beyond what was previously possible.'

How difficult is it to extract DNA from a mammoth?

It's actually, it's quite difficult

because there's only tiny amounts of DNA left.

At the same time you need to imagine that all the bacteria

that lived on that animal deposit their own DNA on top of the DNA

coming from the animal.

'DNA contains the genetic instructions

'used in the development and functioning of all animals,

'but it deteriorates very quickly after death.

'In the case of long dead mammoths, many of the remains recovered

'provide virtually no usable DNA,

'so Schuster uses the plentiful supply of mammoth hair as a source.'

So take me through the process of extracting DNA from a mammoth.

It's actually quite surprising, it's not so unlike what you would do

with your own hair.

So first we wash it, we rinse it with water, we shampoo it,

in the end we even bleach it.

And then we use an enzyme to digest the hair shaft,

and we release the mammoth DNA that's stored on the inside.

'Genetics labs commonly use bone as a source of ancient DNA.

'But frequently contaminated,

'mammoth bones often provide little useable DNA.

'Schuster's use of mammoth hair

'provides a surprisingly pure sample.'

In one instance we working on an individual

that was 18,000 years old,

and we could get more than 90 percent of mammoth DNA from it,

and the oldest specimen that we sequenced

was roughly 60,000 years old, and there we still get

more than 50 percent that is endogenous mammoth DNA.

'Genetic analysis has dispelled a myth about the very source

'from whence the DNA comes mammoth hair.

'Mammoths have traditionally been depicted as having

'orange-brown hair.

'It's now known that they possessed similar genes to

'humans for hair colouration.

'Theoretically they could have been blonde, ginger, or brunette.

'Whatever the colour, the quality of the coat was crucial.

'Like the Arctic musk ox, mammoths sported double layered coats.

'Short, dense, downy hairs next to the skin provided insulation.

'Long, shaggy guard hairs kept out the wind, rain and snow.

'Thick hair is an obvious cold weather adaptation,

'but now advances in genetic studies provide us

'with detailed insights into molecular level adaptations,

'allowing mammoths to cope with the extremes of the Ice Age.

'Dr Kevin Campbell of Manitoba University in Canada investigates

'how their blood evolved to cope with the freezing conditions.'

What I'm really interested in is the protein haemoglobin,

the primary component of the blood.

This protein is really the interface between the atmosphere

and the cell, you know,

it's that transporter protein of all the oxygen in the body.

'Kevin usually studies mice, and how the haemoglobin in their blood

'delivers oxygen to their cells, especially in cold weather.'

'But his childhood obsession with mammoths prompted him

'to try to see if he could figure out how well the haemoglobin

'in mammoth blood worked in the extreme cold of the ice age.

'However, blood dries up and decomposes quickly,

'so no mammoth haemoglobin has survived

'in any of the specimens discovered so far.

'But, because Kevin had the mammoth instruction

'manual in the form of their decoded DNA, he was able to compare

'their code for making haemoglobin with that of their close relatives,

'modern elephants. There were only four differences between the codes.

'This enabled Kevin to use host bacteria to produce

'his very own protein based on modified elephant DNA.'

And effectively we turned it into mammoth DNA. Functional mammoth DNA.

A functional protein that has been extinct for thousands of years.

For thousands of years.

A functional protein that hasn't existed in any animal for thousands of years, that's amazing,

it's starting to sound a bit like Jurassic Park.

And it's not even just functional it's authentic.

This is, in essence, virtual time travel.

The end product is precisely the same, had I gone back in time

and taken a blood sample, it is absolutely authentic.

That's absolutely remarkable and once you've got the mammoth

haemoglobin then you can test it, you can see how it does.

You can look at how it picks up oxygen and how it lets go of it.

Precisely the same way as I would take it from your blood.

'In most animals, haemoglobins ability to deliver oxygen

'to body tissues decreases at low temperatures.

'To see if mammoth blood had any special adaptations to the cold,

'Kevin tested the haemoglobin he'd created

'across a range of temperatures.'

And sure enough, when we looked at the haemoglobin of the mammoth

versus that of the living animals, at normal body temperature,

around 37 degrees Celsius, their properties were the same.

It has the same abilities to pick up and offload oxygen.

But what about at low temperatures?

Yeah, so as temperatures went down, the abilities diverged.

So as temperature got lower and lower,

mammoth haemoglobin, we found, was more able to offload oxygen

than that of the Asian elephant, and far better than that of humans.

It is incredible to be able to take ancient DNA

and to resurrect a protein from the past.

A protein which hasn't existed in a living animal

for thousands of years,

and once we have this protein we can look at how it behaves.

Mammoth haemoglobin can deliver oxygen at very low temperatures,

meaning that mammoths could let their legs,

their extremities GET cold.

And they could then hold on to their body heat,

and conserve energy through the long cold winters of the ice age.

It was crucial to survival.

'These new molecular level investigations are bringing

'the science-fiction style possibility

'of cloning a mammoth ever closer.'

'In the far east of Siberia an incredible new discovery

'is being heralded as the holy grail of mammoth science.

'In the city of Yakutsk, members of the International Mammoth Committee

'have unearthed a completely intact frozen mammoth thigh bone.

'Although thousands of years old,

'it's one of the best preserved bone specimens

'retrieved from the permafrost.

'So perfectly frozen that it contains pure mammoth bone marrow.

'This could be the best source ever of fully intact mammoth cells,

'with undamaged DNA.'

THEY TALK IN JAPANESE

'The marrow will be sent to a lab in Japan where they will try to extract

intact cell nuclei, and insert them in to a host elephant egg.

'If successful,

'scientists there predict that they will be able to clone a mammoth

'by using a female elephant as a surrogate mother within five years.'

'But the ethics of creating such a clone

'is likely to kick up a storm of debate.

'Should scientists even be attempting

'to resurrect an extinct species?

'Rather than trying to clone a long-dead species,

'many scientists are far more eager to understand why the mammoths

'died out in the first place.'

'Their extinction coincided with the warming climate

'at the end of the ice age.

'The environment they'd perfectly adapted to was changing.

'The blue skies that created the steppe grew heavy with cloud.

'Rain returned to the North.

'Dry grassland was replaced with wet tundra plants and forests,

'the mammoths' favoured food supply was dwindling.

'But the genetic studies completed recently,

'suggest that woolly mammoths

'had coped well with similar changes in the past.

'A population crash occurred,

'30,000 years before they finally disappeared.

'But they recovered, suggesting that something else,

'other than changing habitat may have spelt the end.'

The mammoth had survived through many fluctuations in the climate,

through all of these warming and cooling cycles,

why was it at the very end of the ice age

that they seemed to give up?

It might not have been an all-or-nothing process,

that it's just depending on this one last cycle.

It might actually have been a gradual process that after

every warming and cooling period, that not only the population

numbers but also the diversity of the animals went down.

'Professor Dan Fisher thinks he might now have the answer.

'After analysing hundreds of ancient tusks

'from different mammoth species,

'he's uncovered a pattern suggesting

'that mammoths were being increasingly hunted

'by predators as the climate grew warmer, and their numbers dwindled.'

So, you've obviously seen changes in lots of tusks

that you think are evidence of predation pressure.

So, what are those changes,

what was going on in these mammoth populations?

The changes that we see that seem best

explained by increases in predation pressure,

are things like maturation at a younger age, calving intervals,

or intervals between calves in females

that are, if anything, shorter,

in other words these are changes that are reasonable responses

to a changing balance of risk between survival and reproduction.

It's better if there's more predation going on

to reproduce a little bit earlier, even if it's smaller body size.

And to have a few more calves,

even if there's less investment in individual calves.

It's a better bet, so to speak, in the long run to have that

kind of a life history in a regime of higher incidence of predation.

So I think the evidence is that human hunting was an extremely

important aspect of what drove the extinction.

'If Dan Fisher is right it's a huge step forward

'in explaining mammoths' extinction.

'He's sure mammoths were maturing fast and having babies early towards

'the end of the ice age, a classic sign that they were being hunted.

'But in Siberia, the evidence that, that predation was by man is scarce.

'Now potential new evidence has surfaced.

'Dan's colleague, mammoth hunter Bernard Buigues,

'thinks he might have made a new discovery which could support

'the idea that humans hunted mammoths to extinction.

'In a secret location on the edges of the Arctic Ocean,

'thousands of miles away from where I first met him, he's recovered

'a new specimen, which was found frozen in the banks of a river.

'He's suggesting it shows signs of human interaction

'this could be a missing link in the human/mammoth puzzle.'

CHATTER

'I seize the chance to witness such a find and fly back to Siberia

'to meet Bernard, who's transporting the mammoth

'across the frozen tundra.

'We agree to rendezvous in the remote wilderness of Yakutia.'

Well, this is it, this is the rendezvous point.

And I know they're on their way, I can't hear anything yet though.

But it is incredibly cold. I hope it's worth it.

They're bringing this mammoth in,

they're going to eventually take it to Yakutsk,

and we'll be able to have a look at it there,

and hopefully it will be another piece of the puzzle.

It will add to our understanding of these ancient creatures

that once roamed around this landscape.

Oh, I think I can see them.

Can you see the lights over there, on the horizon?

They've just crested the hill.

Oh this is fantastic, it's just so exciting.

Bernard! Oh, my God!

-You've done it.

-Yeah, yeah, yeah.

Oh my goodness, and where's the mammoth?

The mammoth is laying like this yeah,

he's on the back with the four legs up,

and it's a young mammoth.

Yeah, it's smaller than I expected.

It's a wonderful specimen, you will see. I want to show you.

-Oh, fantastic.

-I want to show.

-Oh, that's brilliant.

-I want to share with you.

-All right, lovely.

'We board an ex-military transporter plane

'to travel a further 500 miles south,

'where we'll start the analysis of the mammoth

'in a permafrost ice cave.

'Will this frozen carcass reveal any clues to help explain

'the mammoth's extinction?'

I can't wait to see it, it's travelled all this distance.

It is like unwrapping an ancient mummy. It is an ancient mummy!

It is an ancient mummy, sure.

-The trunk.

-It's the trunk.

It's beautiful.

SHE GASPS

Oh, my goodness! Oh, my goodness, that's amazing!

Long hair, yeah.

That fur's really long.

'From its size it looks as though this mammoth

'was about 3 or 4 years old when it died.

'After thousands of years lying frozen in the ground

'it's twisted and contorted. Now lying on its back,

'it's head is flopped to one side and its legs stick up in to the air.

'Its foot pads and thick strawberry blonde hair

'are exquisitely preserved.'

I'm jealous. He has much more hair than me!

Isn't it hard to believe that this is something which died

so long ago? I mean it doesn't look like an animal which has been

dead for thousands and thousands of years, an animal from the Ice Age.

You can't believe that it's more than 10,000 years old.

It looks so fresh, it looks almost alive.

So fresh yeah, yeah, yeah.

-It is beautiful.

-It IS beautiful.

'This specimen is also mysterious.

'We don't yet know if it's male or female, or when it died.

'But most mysterious of all are the signs of human interaction.

'It has two large cuts on its back,

'through which many of its bones have been removed,

'including its spine and skull.'

So this is very clearly not natural processes,

this is absolutely human tampering.

The really big question is, did this happen recently,

or did it happen in antiquity?

For me definitely it happened a long time ago.

A long time ago, because, can you see, the skin is dry, yeah,

mummified, I can not see how it can be cut.

And it's not so easy to open it,

and of course, we need to work more on this.

Yeah, and this is a wonderful, wonderful thing.

You know, it's an amazing specimen of a young mammoth,

and this is just the beginning, isn't it?

Because now the investigation will proceed,

and we will find out as much as we possibly can

about the life and the death of this animal,

and the way that humans interacted with it.

Yes, this is exciting, this is very, very exciting.

It's actually very difficult to see anything with

the mammoth in this frozen state.

The scientists are going to have to defrost it to get

to the bottom of this story.

How exciting though if they do find out that this mammoth was

tampered with by ancient people.

'If it was interfered with in the deep past,

'this would be an incredibly important specimen

'showing interaction between ancient humans and woolly mammoths.

'People usually kill animals for food.

'But this specimen hasn't been butchered,

'and although now dried out, most of the meat is untouched.

'Humans have certainly interfered with this carcass.

'Bones have been removed and the tusks are missing.

'But for me, the big question is

'whether that happened very recently or in the deep past?

'The scientific investigation is only just beginning

'it may be years before we have the answer.'

It is so exciting, and such a privilege,

to be here with this mammoth as it's unwrapped,

and to have been with it on its journey,

as it comes in from the tundra.

It's a historic moment for Yakutia, for Siberia

and anybody that's interested in mammoths.

'Iconic and majestic, mammoths were once a mystery.

'Now we understand them better, we still revere them.

'Perfectly adapted, on the inside and out,

'they withstood the extremes of the Arctic Ice Age,

'while few other animals could.

'Genetic and chemical analyses are revealing

'the secrets of their lifestyles.

'Long gone from our landscape, we're taking a step closer

'to bringing back these incredible beasts

'using the latest techniques in cloning.

'And this brand new discovery may well take us a step closer

'to understanding how our own ancestors

'could have contributed to the extinction

'of the greatest of all ice age titans, the woolly mammoth.'

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