The Rhone Valley in southern France.
A small promontory of white limestone
stands on a slope covered with evergreen oaks.
This outcrop has been attracting the attention of archaeologists
for about 30 years.
It conceals a cave
that was regularly occupied in prehistoric times.
Thanks to the work of Ludovic Slimak's team,
we know that this cave was occupied by Neanderthals and Homo sapiens.
In 2015, after more than 20 years of excavation,
another extraordinary discovery was made.
Numerous fragments of a Neanderthal jawbone
containing DNA, part of a skull and several phalanges were found.
The investigation to date and analyse
this extremely rare archaeological material is an international effort.
Does the Mandrin Cave shed light on the disappearance
of the Neanderthals, who lived on the Eurasian continent
for 300,000 years,
and the arrival of the first Homo sapiens?
Could the two species have met here in the Rhone Valley?
It is one of the most exciting archaeological thrillers
of our time.
By the early 2000s, Neanderthal DNA had been found at only a dozen sites
across Eurasia, from Spain, France, Belgium, Germany and Croatia
to Siberia, but no findings had been made
near the Mandrin Cave in south-eastern France.
The lack of evidence in this area made it difficult to understand
how Homo sapiens replaced Neanderthals
around 42,000 years ago.
The Mandrin Cave has played an important role
in the lives of archaeologists Ludovic Slimak and Laure Metz
for over 20 years,
largely thanks to its exceptionally well-preserved soils.
How has the Mandrin Cave preserved so many flints and bones -
precious relics of the Palaeolithic period?
Excavations at Mandrin have identified
ten main archaeological layers.
Layer A is from the present day.
The oldest is J.
Over a period of 70,000 years,
up until the arrival
of modern humans around 42,000 years ago,
several distinct cultures succeeded one another.
Archaeologists are particularly intrigued by layer E.
What surprised the archaeologists was the sheer number
of pointed objects, probably arrowheads.
They come in two basic shapes,
5cm long and 4mm to 5mm thick,
or less than 3cm long and 2mm to 3mm thick.
These are highly unusual arrowheads which, according to Ludovic,
point to another intriguing find in a nearby cave.
The 1,500 pointed objects in layer E are very mysterious.
Apart from the pointed objects in the Neron Cave,
they bear no resemblance to any other Neanderthal tradition.
Their discovery has raised a host of questions.
By studying the way in which flints are produced,
archaeologists can distinguish between different cultures
and different periods of prehistory.
Traceology, on the other hand, seeks to understand
the function of these flints and how they were used.
Laure Metz is a traceologist who has been working on
the Mandrin Cave scientific project for almost 20 years.
Laure's first clue were the fractures present
on a large number of the micro pointed objects found in layer E.
The cause of these fractures raises questions.
Only projection from a bow could have caused them,
but bows are associated with much later periods of prehistory.
To find out more, Laure invited Christian Trubert,
an expert in prehistoric archery, to conduct some experiments.
They start by making arrows.
Around 15 arrows, designed to be as prehistoric as possible,
were made from glue, natural string
and carefully selected wooden shafts.
Laure has already carried out several experiments
using different means of propulsion
without being able to reproduce the fractures found on the tips.
This time, as if in a hunt,
the archer will shoot an arrow at a goat carcass.
After each shot, Laure records the information needed
to trace each arrow fragment.
Armed with his bow,
which is as prehistoric as the shafts fitted with micro arrowheads,
Christian Trubert aims for the animal's ribcage.
CAMERA CLICKS
Before she can complete her analyses,
Laure and Toumai Boucherat, a surgical expert,
must extract all the flint arrowhead fragments from the body.
The operation resembles an autopsy.
FLIES BUZZ
D'accord.
After recovering all the flint heads,
Laure examines them under a microscope.
This experiment shows that the mysterious pointed objects
found in the E layer were hunting weapons.
So who were these technologically advanced hunters
that frequented the Mandrin Cave 54,000 years ago?
A study of other collections revealed that very similar heads
were found at a site in Lebanon.
So the Homo sapiens groups at both the Mandrin and Lebanese sites
were very close cousins.
But how was it possible for a group of sapiens
from the eastern Mediterranean to travel to Mandrin,
some 4,000km away?
According to Ludovic, they may have come by sea.
The study has revealed that Homo sapiens
from the other side of the Mediterranean,
armed with bows and arrowheads,
occupied the Mandrin Cave around 54,000 years ago -
12,000 years earlier than previously thought.
Further insights into this extraordinary discovery
were uncovered thanks to a surprising find.
Ludovic discovered that the surprising smells
emanated from small stones that had broken away from the cave walls.
The study of the small soot stones
was entrusted to one of the young archaeologists at Mandrin.
Segolene Vandevelde's task promised to be a difficult one
as the study of soot is very rare in archaeology.
Microscopic examination of these rock fragments
opens a window on tens of thousands of years of history.
The sample contains several thin layers,
or films, of soot, as well as calcite rock.
The calcite is made up of alternate layers of large and small crystals.
Each fragment was photographed,
the films of soot noted and the calcite doublets measured.
The information is then converted into a diagram.
After establishing the sapiens' occupation dates in layer E,
Segolene does the same for the Neanderthal occupations in layer F.
So the sapiens replaced the Neanderthals very quickly.
Segolene would like to determine the length of time
between their respective occupations.
To do this, she is counting on a chemical element
present in limestone which is known to be annual - strontium.
An experiment at the CEA's microspectrometry laboratory
should provide her with this information.
The high-resolution record of the Mandrin Cave occupations
show that Homo sapiens lived alongside Neanderthals
for a few years around 54,000 years ago,
before leaving Mandrin and this river bank for good.
According to Ludovic, they may simply have moved
to the opposite bank.
He's observed that after the Homo sapiens left,
the flints that had always been found on both sides of the Rhone
were only found on one side.
The appearance of Homo sapiens around 54,000 years ago
in the Mandrin Cave has radically changed the story
of their arrival in this part of Europe.
After more than 15 years of digs,
the archaeologists now want to explore outside the current cave,
which, 50,000 years ago, was covered by a rock fault.
This area is now protected by a Plexiglas roof.
Ludovic was immediately struck by the Neanderthal character
of these teeth and their remarkable state of preservation.
The Centre for GeoGenetics in Copenhagen
is one of the world's leading laboratories for ancient DNA.
The investigation into the Neanderthal sample
was led by Martin Sikora, assisted by Tharsika Vimala,
two specialists in palaeogenetics.
The first part of the investigation was entrusted to Andaine Seguin.
She had the formidable task of extracting DNA
from the badly damaged sample.
The risk of losing precious genetic data is high.
Extracting DNA from this ancient sample
requires great care and a highly specialised procedure.
The other difficulty is that the ancient DNA
is contaminated by other DNA, such as soil bacteria.
This forces Andaine to use an ingenious palaeogenetic technique.
Their mastery of these intricate palaeogenetic techniques paid off.
The DNA recovered was not complete but it was of exceptional quality,
especially for a Neanderthal.
When I was really happy is when you told me that
the way I proceeded in the lab... Mm.
..somehow saved the sample, because it was super contaminated
and it was super damaged
and it was with super low endogenous content,
so super low percentage of human DNA.
It looks really good. I'm very positive.
And we are lucky it's a male, so it has a Y chromosome. Exactly.
And we don't have that many male Neanderthals represented.
It didn't take long for the first results of the DNA analysis
to reach the Mandrin Cave.
The jawbones were entrusted to the PACEA laboratory
at the University of Bordeaux.
Clement Zanolli, a palaeoanthropologist
specialising in dental structure, was in charge of studying
these precious remains - essentially teeth and jaw fragments.
Each tooth was scanned with a microtomograph,
providing extremely high-definition images
of both tooth morphology and internal structure.
Clement Zanolli's initial investigations
confirmed the geneticists' conclusions.
This was indeed a Neanderthal.
This wealth of material - 31 teeth and several bone fragments -
should enable us to learn a lot more about Thorin.
Clement had to assemble as many fragments as possible
to offer the most complete digital reconstruction of the individual.
Clement Zanolli invited Dr Esclassan,
professor at the Marseille School of Dental Medicine,
to review this remarkable Neanderthal treasure.
Clement Zanolli's analysis of Thorin has enriched the profile
of this Neanderthal individual.
Although very incomplete,
it has made the archaeologists even more excited.
Only about 15 Neanderthal individuals this well documented
are known to us.
Excavations resumed in the area where Thorin's remains were found.
The hope is to find more of his bones.
Hundreds of artefacts have been unearthed, most of them small -
numerous tiny bone fragments and flint chips.
To find out what these bone fragments are
and if they belong to Thorin, Ludovic uses a new technique
developed at the University of Manchester
which can identify even the smallest bone fragment.
Mike Buckley, the inventor of this formidable technique known as ZooMS,
recently received a package from the Mandrin Cave.
A bag of tiny bone fragments.
Thanks to ZooMS, it should be possible
to make the protein collagen found in bone tissue talk.
One of the main benefits of looking at collagen
as a target for what we analyse with ZooMS
is that it is a very stable protein
that has retained its original signatures
for these hundreds of thousands, if not millions of years.
The samples undergo a series of treatments
to extract collagen from the bone tissue.
They are then prepared for the mass spectrometer.
OK, now, here we are at the MALDI mass spectrometer.
I just need to load in the target plate.
The ZooMS method enables Mike
to make an inventory of all the species present in the samples.
It was really quite exciting when we analysed just the first batch
of around 400 samples.
We saw a good amount of this aurochs,
a bovine.
We saw also a good amount of horse and deer,
a much smaller amount of cave bear.
But what was really interesting was that we had three samples
that gave a hominin signature,
and we can subject that to the radiocarbon dating process.
The three human bone fragments identified by Mike Buckley
are sent to Tom Higham's radiocarbon dating laboratory in Oxford.
Tom Higham is a specialist in carbon-14 dating.
So, in radiocarbon dating, we use a particle accelerator like this
to measure single atoms of carbon-14.
The more carbon-14, the more recent or modern something is.
The less carbon-14, the older it gets.
We can go back to a maximum age of about 50,000 years ago.
But as we get back beyond 40,000 years ago,
we have big challenges in getting the right date
because of contamination that builds up in the bone and charcoal
and other organic samples in these archaeological sites.
The risk of carbon dating errors for bone fragments this age is real.
When we first explored the radiocarbon date of Thorin,
we got a date of around 41,000 years ago.
Thorin is towards the end of the Neanderthal lineage
but he's not the latest Neanderthal.
In Copenhagen, Tharsika has completed
a first phase of analysis of Thorin's genetic material.
Here we have all the reads that are sequenced
for the mitochondrial genome... Mm-hm.
..and we are actually getting a lot of reads
for each position of the mitochondrial genome,
so that's very good.
It allows us to get some higher certainty for our analysis.
That's very good.
Did you already make a tree to have a look at? Yes, I have a tree.
I have it right here.
I'm using all the Neanderthals that we have data from.
What's actually really interesting about this analysis
is that Thorin is not clustering with the other late Neanderthals
but, actually, he's, erm...
..actually grouped together with one other Neanderthal.
Yeah, that's super interesting. So what is this closest...?
The closest one is the Mezmaiskaya one.
So the dating of the Mezmaiskaya one is a little bit uncertain,
but around 70,000, 80,000 years old.
So it's clearly not a late... So it's not a late Neanderthal, no,
but one that he's sharing the most genetic variation with.
Well, that's quite surprising, no? I mean... Yeah.
As far as we know, all the archaeological data
points to a much more recent age. Exactly.
It's, like, double the age of what we would have expected.
It's just a very crude analysis. Exactly,
because I'm not using that many parameters here,
I'm just counting the number of mutations that are different
between the Neanderthals and then calculating the age based on that.
We should have another look at trying some more models with...
Yeah. Yeah, and we should also talk to Ludovic about this,
because this really doesn't agree with what he has said about
the dating. I think they're not going to be too happy about that.
According to the genetics, it's not a late Neanderthal,
it's an early Neanderthal.
Thorin's genome is quite different to Western European Neanderthals
dated to around 50,000 years ago.
He is genetically closer to a Siberian individual
dated to 80,000 years ago.
This makes Thorin genetically isolated
and much older than the archaeological layer
where his bones were found, which is dated to 42,000 years ago.
The dating to 105,000 years ago threw the team into turmoil.
Tom Higham decided to go back to Thorin's dating.
The first time we used this method to radiocarbon date Thorin,
we got a date that was just over 41,000 years ago,
but we could see there was a potential problem with the sample.
We had some indications in the chemistry
that it wasn't quite right, and so we asked for more material
to see if we could radiocarbon date the sample again.
And, fortunately, there was more material -
a single piece of bone - that we could date,
and, using this material, we were able to date the sample not once,
not twice, but three times
to make sure we absolutely had the right date.
All of the results that we got were statistically the same
and they indicated that the sample was more than 48,000 years old.
Back in Copenhagen, the geneticists discovered that the genome
of a Neanderthal from Gibraltar recently made public
displayed very strong parallels to Thorin.
Hi, Ludovic. How's it going?
Oh, nice to see you. Nice to see you. I hope all is well.
So we have some quite nice new results
in terms of the relationship of Thorin
with some of the other Neanderthal genomes we've been looking at.
We do find some similarities with Iberian Neanderthals,
in particular these ones from Gibraltar,
from the Forbes' Quarry site, so, I mean, maybe Tharsika
can elaborate a bit more on what exactly we're finding.
Yeah, so what we are finding from our DNA analysis
is that Thorin is very similar to these early Neanderthals,
so the Neanderthals that lived around 100,000 years ago,
and not so much like the late Neanderthals -
the ones that lived around 40,000, 50,000 years ago,
which is very interesting
because that was not what we had expected to see.
The issue with Forbes' Quarry
is that we don't actually have confident dating of the remains.
We just have a genetic profile.
Now we have something that match with the Thorin population...
Exactly. ..but Forbes' Quarry, it was excavated
in the middle of the 19th century.
There is no true archaeological context,
but, as far as I remember, yes, they proposed an age,
and they are talking of something from 80,000 to 100,000.
With this group of Neanderthals, we have nothing
to actually calibrate with, and that means
there are some uncertainties in our molecular clock estimates.
Do you think you could use the Thorin data
to try to calibrate the Forbes' Quarry data?
This is exactly what's interesting,
because if Thorin is closer to the early Neanderthals,
then we could use your dating from the layers as a calibration.
So we can put in that Thorin is 45,000 to 50,000 years old
and then we can see, well, do we get any different estimates
for the surrounding Neanderthals
that have a similar genetic profile as Thorin?
This change a lot all what we understand
about the late Neanderthal because, if I follow you well,
Forbes' Quarry in southern Spain and the Thorin population
should be one population,
and this population is deeply divergent with the late Neanderthal.
So, if you're right, we could draw a Mediterranean population
but go from southern Spain to the Rhone Valley, so something huge.
That would be interesting because that would suggest
that we have one population staying in one place,
not interacting with any of the new Neanderthals coming in.
I don't know how likely that would be.
In terms of DNA,
Forbes' Quarry and Thorin should be the same age.
Yeah, I mean, it would point to that, right?
It could be part of the same metapopulation, if you want.
And so we would have process of isolations
between Neanderthal population
that would also fit very well with your genetic data
that show that there's a question of isolation. Yeah, no, absolutely.
I think this is definitely something we should try, right,
so I think that's... Yeah. It would be very nice.
And it would be a cool story.
A fantastic one. Yeah.
The archaeologists also await the results
of a new direct dating study of Thorin,
carried out by Renaud Joannes-Boyau
of Australia's Southern Cross University.
Hi, Renaud. How's it going? Good. How are you, Tom?
Yeah, great. As you know, we have a kind of difficult,
challenging situation at the moment here.
We've got the radiocarbon dates we've done on Thorin,
which are very consistent in telling us
that the radiocarbon age is around 49,000 years ago,
but the genetic estimates for the age of the mitochondrial lineage
are estimated to go back much, much earlier than that -
more than 100,000 years, perhaps even 120,000 years.
That's where you come in
and your techniques of ESR and uranium series dating.
So we have the results already.
We conducted some ablation around the enamel and dentine,
looking at the diffusion of uranium inside the tooth.
What we can say is we have a minimum age
of about 43,000 years ago. Wow.
Yeah. The problem with the uranium series
is, of course, it's a minimum age... Yes.
..so one could argue that it could be actually much older. Right.
So what we do is we measure how much radiation, radioactivity,
has been received by the enamel
and that gives us an intensity of the signal... Mm.
..and that intensity, we translate that in years,
and we have an age of 48,000 plus or minus four.
Oh, brilliant. So that brackets the age.
Either it's older than 43 and younger than 48, right?
And younger than 52.
Oh! Oh, wow, wow, wow. That's brilliant.
That's really exactly where I'd hoped that the results would sit.
But what's clear is that it's very, very different from the estimate
on the mitochondrial DNA and the other genetic data,
so it looks as though Thorin is in the last few thousand years
of the Neanderthal lineage in Europe.
We know that European Neanderthals disappear
between 39,000 to 40,000 years ago, so he's around 10,000 years
older than that, plus or minus a couple of thousand.
Thorin is now considered a late Neanderthal.
The same goes for his closest cousin from Forbes' Quarry.
These Mediterranean Neanderthals, isolated for over 50,000 years,
form a completely new Neanderthal population.
Finally certain of Thorin's age
and that his closest relative is in Gibraltar,
Ludovic travelled to the southernmost tip of Europe.
He was eager to compare his thoughts
with those of the archaeologist Clive Finlayson,
who has been leading research there for the past three decades.
So this is the famous Gibraltar 1 skull, Neanderthal skull,
from Forbes' Quarry, found in 1848.
And this is the one that recently had DNA extracted from it.
It was very... Almost miraculous. Yeah.
If you look at it, to me, it looks very gracile compared to some
of the other Neanderthals. I know they've got the large eye sockets,
they all have that, and the large nose,
but, really, in terms of brow ridge, it's quite a gracile Neanderthal.
We know that the skull can't be more than 45,000 to 50,000...
Well, I'm going to let you in on a secret here.
We found the levels where we think this skull was found,
we're quite sure, and we've dated it with uranium-thorium
above and below, and it's sandwiched in between
60,000 and 40,000 years ago. LUDOVIC CHUCKLES
Ludovic was delighted to learn this,
as it confirmed that the Neanderthal at Forbes' Quarry
was roughly the same age as Thorin.
Clive took his visitor
to the impressive Gorham and Vanguard cave complex.
So, here we are. This is... You're going to see Vanguard Cave... Wow.
..and Gorham's Cave is around the back.
We're in the southernmost tip of Europe.
What you see over there is the coast of North Africa.
It's very, very near. Wow.
Come to the lost world, as I like to call it.
LUDOVIC LAUGHS Thank you.
People - Neanderthals - lived here for maybe 100,000 years.
Welcome to Vanguard Cave.
Whoa!
Huge cave. CLIVE CHUCKLES
Fantastic.
Just like the Mandrin Cave,
the remains of Neanderthal occupations
have been extraordinarily well preserved
by the continually drifting sand.
If we make a reconstitution of what was the landscape
in that time period, by 50,000 years ago, 60,000,
so the sea was lower?
During that period, the sea level can drop to a maximum of 120,
but it's really... The average may be minus 80m for a long time.
The coast is 4km away.
It's not dense woodland, it's open with trees and you have these lakes.
Now we have genetic connections. Yeah.
The population we have here in Gibraltar
are the population we have in Mediterranean France. Yeah.
Well, that's very exciting for us to hear that,
but, for me, it was music to my ears to hear
what is going on with the genetics.
It's a wonderful connection to have.
What we see is that this population are the same.
They are genetically the same population.
And... And they are isolated by
most of the European classic Neanderthals for a very long time.
We know that Neanderthals were mixing with other Neanderthals
and with other modern humans sometimes, and so on,
so it's not that they weren't capable or didn't want to... Yeah.
..there must have been some other kind of barrier... Exactly.
..which perhaps was a biogeographical ecological barrier,
maybe then supported by maybe cultural barriers.
What is important, we see the landscape, we are facing...
There are cliffs along the sea and a lot of mountains,
very high mountains. My feeling is that what we may be looking at here
is a corridor which connects...
Maybe it's counterintuitive, but it connects from here
to France on the Mediterranean coast.
The Mediterranean Sea was 100m lower during this Ice Age,
allowing people to travel along the coasts of Spain,
France and Italy.
It was possible to travel from Gibraltar to Mandrin
along this coastal corridor.
Now we know that this Neanderthal world
is much more complex than what we thought
and it's not a question of two populations, it's at least three,
and so we should have the classic Neanderthal,
we should have the Homo sapiens, of course,
and then we should have this Mediterranean population...
Population. ..on which we didn't know anything a year ago.
And we need to start looking at this new world of the Neanderthals.
When we came down into the cave, I said, "Welcome to the lost world."
LUDOVIC LAUGHS I didn't really realise
that it wasn't just this cave I'm talking about,
that all that, in many ways, is a lost world.
This makes a lot of sense
and this is very rich for the future, I think.
At the moment, we're in the verge of a change of paradigm, I think.
We just opened a window. Opened a window, absolutely.
The Mandrin Cave is a long way from revealing all of its secrets,
but several major discoveries have been made.
The arrival of the first sapiens in Western Europe
has been brought forward by more than 10,000 years.
For the first time, a genuine encounter
between our species, the sapiens, and the Neanderthals
has been proven to have occurred here.
And, incredibly, Thorin's discovery
revealed a brand-new Neanderthal population...
..isolated for 60,000 years on the shores of the Mediterranean.