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This documentary charts an astounding archaeological investigation that has discovered the remains of an entirely new species of human ancestor...
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00:02Ever since Darwin put forward the idea that we evolved from apes,
00:06scientists have been searching for evidence of the first creatures that left the ape world
00:11and crossed into ours, the so-called missing link.
00:16But these bones are extremely rare,
00:19allowing only fleeting glimpses of how we slowly changed from ape to human.
00:27Now, deep inside remote underground chambers in South Africa,
00:32not one but two new species of hominids, our ancient ancestors, have been discovered.
00:39There it was, right there.
00:42One of the most spectacular early hominids ever discovered lying on the surface of a cave.
00:48And not just a few bone fragments, there are thousands.
00:52It's everywhere.
00:56Oh, beautiful.
00:58The first thing that came through my mind was Howard Carter's anecdote about opening Tutankhamun's tomb.
01:05It was Lord Carnarvon in the back saying, you know, what do you see?
01:08And Carter says things, wonderful things.
01:14We have found a most remarkable creature and a most unexpected one.
01:20This is the story of a discovery that could rewrite the history of our evolution and transform our understanding of
01:28our human origins.
01:29We realize all of our preconceived notions have to be tossed aside.
01:34And this unique find is already throwing up revolutionary new theories about how our earliest ancestors lived and died.
01:44It looks like they got in there because somebody put them there.
01:50Now, if we say that, you have to understand, that's a very controversial thing to say.
01:55Were these primitive creatures burying their own dead?
02:00Right now, it looks a lot like that.
02:03Will it hold out to be that?
02:06That will be a mystery I want to see solved.
02:19In autumn 2013, cave enthusiasts Rick Hunter and Steve Tucker set out to explore a deep cave system near Johannesburg
02:29in South Africa.
02:32It's called Rising Star.
02:36It's an amazing cave. It's got a bit of everything.
02:39There's tight squeezes, some great climbs, beautiful formations.
02:44Rick and Steve were planning to document Rising Star's spectacular crystal stalactites.
02:50But they were about to find more than they bargained for.
02:54I wanted to show Rick a great climb in the cave called the Dragon's Back.
03:02And in the process of taking some video of the formations at the top of it, Rick wanted to get
03:08past me.
03:14So I went down a small little crevice, basically so that Rick could crawl over me.
03:21I was just getting out of his way.
03:23And as I went into it, I noticed that there's still a little bit continuing down.
03:33As Steve squeezed into the crevice, he realised there was a void beneath his feet.
03:41He'd stumbled onto a hidden chamber, undiscovered by previous explorers.
03:47So my legs were dangling down this last little bit, and you don't feel anything below you.
03:52And the only way to climb down is actually to keep on lowering yourselves until your arms are almost fully
03:57stretched out.
03:58And then you start to feel a couple of rocks that you can actually put your feet on.
04:06Curious to explore this unmapped part of the cave system, Steve and Rick dropped into the hidden chamber.
04:14Above their heads, they saw rare rock formations.
04:21But the real discovery was beneath their feet.
04:25We saw at first one bone lying around.
04:29We looked around a bit more, and, well, another bone.
04:35We actually spotted teeth in the rocks and realised we actually had found something.
04:41Followed by a skull in the ground.
04:47And finally, one of the most interesting ones, the mandible.
04:50With four teeth in it.
04:54The cavers had no idea what kind of bones they were looking at.
05:02They decided to take photographs of their find to a leading expert in the study of human origins.
05:09Lee Berger is a professor of paleoanthropology at the University of the Witwatersrand in South Africa.
05:18For 18 years, he'd been searching for the elusive remains of our ape-like ancestors.
05:26But nothing prepared him for what Rick and Steve were about to show him.
05:32They flipped open a computer, and I saw something I don't think I ever dreamed I would see on a
05:42computer screen.
05:43That was a mandible of what was clearly an early hominin.
05:50The teeth, just perfect.
05:52The next picture had a skull in it of a hominin.
05:56I could see it in outline.
05:59There were bones everywhere.
06:01Every one of them I could see in the image were hominin.
06:08I was a bit in shock.
06:11Because it all went like a car crash for me.
06:14You know, it really did. Black and white.
06:16And I have only visual, not audio.
06:22Lee instantly recognised the bones were from some kind of hominid.
06:27Creatures from the human evolutionary line.
06:33These early human fossils are probably the rarest sought-after objects on Earth.
06:39We in paleoanthropology sit in one of the few fields that probably have more scientists studying objects than there are
06:46objects to study.
06:47In fact, the vast majority of people who do what I do will never find a single piece of one
06:52of these early humans.
06:54And if they do, it's going to be an isolated tooth.
06:57Probably 80 to 90% of our record are just little bits of isolated teeth.
07:06The photographs from the chamber at Rising Star suggested Rick and Steve had stumbled onto a treasure trove.
07:14Could this discovery illuminate one of the great mysteries about our origins?
07:22Exactly how we evolved from ape-like creatures into human beings.
07:27There's a big gap in the fossil record with only a few little fragments.
07:32The fossil record suggests that in that million year gap, between two to three million years ago, lies the birth
07:38of the genus Homo.
07:41It's perhaps the least understood and most important episode in our evolution.
07:47On one side of the gap is Australopithecus, an ape-like creature with a tiny brain.
07:54They walked upright, but belonged to the world of the apes.
08:00An Australopithecus is sort of like a bipedal ape.
08:02If you went back in time and saw them walking around the savannah, you would see animals that stood up
08:07and walked like we do.
08:08But they would have been smaller in body size.
08:11Their brains wouldn't have been as big, so their heads would have looked smaller.
08:14Their jaws and teeth were very large.
08:19Scientists believe that between two and three million years ago, these Australopiths evolved into the first recognizably human species, Homo
08:29erectus.
08:33They have big brains and small faces, adaptations for using tools.
08:39So what went on in the transition from the ape-like Australopithecus to the human-like Homo erectus?
08:48Lee Berger hoped the new discovery in the chamber at Rising Star could provide crucial new evidence.
08:55The only way to find out was to bring up the fossils.
08:58I had to make a decision, and about, oh, just before 1am, I decided that history would never forgive me
09:10if I did not act right then.
09:15Recruiting a team of anthropologists capable of excavating the bones and bringing them safely to the surface was not going
09:23to be easy.
09:25The remains lay far underground in deep, inaccessible caves.
09:30In places, the chamber entrance was less than 20 centimetres wide.
09:35I put a call out on Facebook saying, I need skinny scientists who are not claustrophobic, who are cooperative, who
09:48can work together in a dangerous and difficult environment.
09:54I saw Lee's Facebook post, actually, and on a whim, I applied for it, and the next thing I know,
10:02I got asked to interview, and from there, just things started happening really quickly.
10:08I saw a call that came out on Facebook from Lee that was looking for skinny scientists, skinny paleoanthropologists that
10:15weren't claustrophobic,
10:17and that would be able to fit into a slot that was about 18 centimetres.
10:23And that was very intriguing.
10:26I thought I'd get three, four, five applicants. I really did.
10:30I mean, how many people in the world could be qualified and fit that criteria?
10:37Within 10 days, I had 57 qualified applicants from all over the world.
10:44Most of them women.
10:46It really seemed perfect.
10:47In fact, when I read the call out to my husband, he said, well, they might as well have just
10:52meant, you know, written, Marina is wanted over here.
10:56So...
10:57Then I got the email that said that I, I got it.
11:01And characteristically, I bust out crying.
11:07And just kept reloading my email to make sure, refreshing it, just like, really, it's really there, it's really there.
11:16Just five weeks later, Lee and his team of skinny scientists were setting up base camp at the Rising Star
11:23cave system.
11:26Working 25 metres underground would be difficult and dangerous.
11:33Safety lines, lights, cables and cameras had to be installed.
11:40A command post was set up from where Lee could watch virtually every part of the cave.
11:47I really began to get a feel for what I was putting these young women into as the cavers who
11:54were laying over two kilometres of cable.
11:57And I think they were terrified and I was terrified.
12:01They were still untested.
12:02We took them through the caves, testing their capabilities in this system.
12:09Marina, Becca and Hannah have been chosen to go down first.
12:15Still, no one knows exactly what they will find.
12:22The descent is difficult.
12:24And as I looked down, I thought, oh, you know, I don't know if I'm, if I can do this.
12:36So you start by descending down, you know, a fairly narrow shaft and some tunnels.
12:41You get down into an area here.
12:44The team christened this the Superman Crawl, a stretch so narrow that they were forced to crawl on their stomachs
12:51to get into the first main chamber.
12:54This is what we call the dragon's back.
12:56So that's the ridge climb with a sort of four or five metre drop on either side.
13:01At the top of the dragon's back, the scientists faced a vertical shaft dropping 12 metres down towards the hidden
13:09chamber.
13:15Marina is the first to enter the deepest reaches of the fossil cave.
13:23There was a little bit of trepidation, I have to confess, and a lot of excitement to be the first
13:29of the advanced scientists to go into the cave.
13:33The first thing that came through my mind when I went through the final slot into the actual final chamber
13:39was Howard Carter's anecdote about opening Tutankhamen's tomb.
13:46I think it was Lord Carnarvon in the back saying, you know, what do you see?
13:50And Carter says things, wonderful things.
13:55And then I saw them enter this chamber.
14:00We got the camera set up, and you could see their feet moving.
14:06And it was surreal.
14:08The cave is beautiful, just geologically beautiful.
14:12And then you look down, and there was just a sea of bone.
14:16And it was obviously just not regular bone.
14:20So, yeah, it was amazing. Amazing.
14:28A team of scientists in South Africa has embarked on an ambitious expedition to recover the fossilised remains of our
14:36early ancestors.
14:38The expedition leaders watched the recovery team working in a narrow chamber 25 metres below them.
14:46And then the process started.
14:49The process of doing science began.
14:52So we'll put pin number one right beside the mandible, and that's where we'll concentrate.
14:57Okay.
14:58Okay, that's a super.
14:59Okay, thanks.
15:01Bye.
15:05Yeah, that's perfect right there.
15:07Okay, gonna start scanning.
15:08Okay, scan.
15:09Laser scanners and cameras are used to record the size, shape, and position of each precious bone fragment.
15:17It's mapping right now.
15:20Ah, there, they're coming.
15:22Yeah, yeah.
15:22I see what looks like a mandible in the middle there, on the right.
15:26That looks fantastic.
15:28Finally, it's time to bring up the first fossil, the mandible.
15:54All right.
15:58You got the fossil, huh?
15:59Yes, we got the fossil.
16:01There we go.
16:03Now we have everyone else.
16:05Everyone's out.
16:06Rick's out safe.
16:07They're all out.
16:07They're coming.
16:08They're coming.
16:08Well done.
16:11With the jawbone safely brought to the surface, Lee Berger can get his first close-up look at the fossils.
16:19And there is a surprise in store.
16:23When they opened that little box and we unwrapped this thing that they collected, every great idea we had went
16:34out the window.
16:36Gone.
16:36You know, suddenly we didn't know what we had.
16:41When he had first seen the jawbone in Rick and Steve's photos, Lee had decided it probably belonged to an
16:48australopith, the ape-like creatures that eventually evolved into humankind.
16:56Australopiths had large jaws and teeth, but as they transitioned into the genus Homo, their faces shrank, jaws and teeth
17:04became smaller.
17:08When he finally had the jawbone in his hands, Lee saw it was too small to be an australopith.
17:17It seemed quite human.
17:20Could it be a new unknown species that might help scientists fill in the missing links between australopiths and early
17:30Homo?
17:31They had this molar teeth and a very strange use of the frontal part here.
17:41And luckily we got another piece.
17:44So with these two pieces we have a hemimandible which is complete.
17:49And then we can put on the mirror image and we have sort of outline.
17:57This is pure confusion.
18:00We don't know what to make of it.
18:02We realize all of our preconceived notions have to be tossed aside.
18:06We can't go into this thinking it's going to belong in this group or belong in that group.
18:10We just have to start from literally scratch.
18:16The laborious task of piecing together the bones will not only tell the team what these ape men look like.
18:22It may also reveal new insights into how they lived.
18:30Lee Berger knows how a find on this scale could revolutionize our understanding of hominid behavior.
18:38Because remarkably this isn't the first time he's discovered a new species.
18:44In 2008 he made a smaller discovery in the Malapa Valley just a few miles from the rising star site.
18:51The Malapa find has blown apart one of the most controversial theories about early hominids.
18:59The story all began on August 1st 2008 when I came into this valley following targets which were these trees
19:08above my head that I could see on Google Earth.
19:11I walked up that old lime miners trackway which wasn't quite as clear as it is today, mostly overgrown.
19:17I came into this grove and found this little hole.
19:22Lee had brought his nine-year-old son Matthew and his dog Tao along with him.
19:28I stood at the edge of this pit and said go find fossils.
19:31And with that Matthew raced off into the bush here.
19:35I thought he was going to go chase giraffe or zebra or something like that with Tao in tow.
19:39And a minute and a half later he shouted, Dad I found a fossil.
19:43Sitting right over by that lightning struck tree, he had stopped and found a little rock.
19:49And I almost didn't go and look because I knew he'd found an antelope fossil because that's pretty much all
19:54we ever find.
19:55I saw a fossil. I didn't think it was hominid. I just thought it was an antelope because we find
20:01thousands of those.
20:04I started walking towards him though because I had to see what he found in five meters away.
20:10I realized that sticking out of that rock was a hominid clavicle. I couldn't believe it.
20:16And what I saw, stunned me, I climbed down the pit and looked right over here and there sticking out
20:26of the wall was the proximal humerus of a hominid.
20:29I couldn't believe it. I did my PhD on those. I climbed closer and as I got closer I realized
20:34there was a scapula of the shoulder blade in place.
20:37And I came even closer and put my hand on the wall right here. And two hominid teeth fell into
20:45my hand.
20:48One by one they took out blocks of stone they thought might have hominid fossils in them.
20:57The blocks were all taken back to Lee's research laboratory at the University of the Witwatersrand.
21:07Lee's wife Jackie, a radiologist, ran the blocks through a CT scanner, allowing the scientists to peer inside.
21:16Higher. There you go. Okay, that's good, yep.
21:23Inside one of the blocks, a stunning discovery.
21:30A slice came through and you could see an entire skull.
21:34I was dumbfounded. I could not in my wildest dreams believe an entire skull could be sitting in this little
21:43rock.
21:45Its small brain and forward projecting face made it clear that it was an Australopith.
21:51But details of the teeth and other parts of the skeleton made it unlike any found before.
22:01This appeared to be an entirely new species.
22:07Lee called it Australopithecus sediba, after the wellspring near which it was found in South Africa.
22:17The team radioactively dated the limestone layers in the Malapa cave.
22:24The layer containing the sediba skeletons was 1.97 million years old.
22:31That makes these creatures among the last of their kind.
22:36Living right at the end of the fossil gap between Australopiths and Homo erectus.
22:45Here, at last, was a creature that could tell us something about that transition.
22:51And the bones were not just fragments.
22:54Here were two remarkably complete skeletons.
22:57A female and a child.
23:01Sediba was exciting from the get-go.
23:04Right away we knew that we had parts of the skeleton and we had parts of the cranium,
23:09which helps us figure out who this animal is.
23:12So that was really, really exciting.
23:14And initially these upper limb bones looked very primitive.
23:18So we knew that we were dealing with something that looked like it would be a good climber,
23:23kind of an ape-like creature.
23:31The next step was to reconstruct Sediba's skeleton.
23:35Unlike past fossil finds, here the skeletons are so complete there doesn't have to be much guesswork.
23:43By scanning and mirror imaging, missing bones can be filled in with great accuracy.
23:53Layer by layer, a 3D printer then slowly prints the ribcage in fine plaster.
24:04Ah, beautiful.
24:08Finally, the skeleton is complete.
24:13It is highly unusual.
24:18All Australopiths are a mix of ape and human.
24:23But Sediba has a unique mosaic of features scientists have never seen before in the same creature.
24:32The arm is very long, like in a chimpanzee.
24:35But the hand is with short fingers and a very long thumb, like a human hand.
24:41Which was never found until now, because this is the most complete hand ever found in this period.
24:48From the reconstructed skeleton, paleo artist Victor Dieck can start to create a lifelike digital painting.
24:57I have now gone ahead and created a body for it.
25:03And if you want to see, we can check all that by going transparent.
25:08And seeing, making sure that the bones and everything line up in the proper spaces.
25:16So here we have a concept reconstruction of how Sediba potentially could look like.
25:26For the first time in almost two million years, the face of Australopithecus Sediba looks out on the world.
25:39But what kind of creatures were they?
25:42Sediba's bones would reveal secrets that challenge one of the darkest theories about human evolution.
25:58The fossilized remains of Sediba are so well preserved that they're giving us unprecedented insights into how the creature lived.
26:07And they may help to shed new light on one of the most controversial theories about our evolutionary origins.
26:17In the 1920s, anatomist Raymond Dart was studying broken animal bones that had been found alongside hominid remains.
26:29He became convinced that the bones were used as weapons by our primitive ancestors.
26:38Dart had been a young medic in World War I.
26:42He'd seen first-hand the barbarity humans are capable of.
26:49Raymond Dart's experience in the World War may have colored his interpretation of what these bones and teeth meant.
26:56You know, it gave him a view of sort of the dark side of humanity and the violence of humanity.
27:01And he came up with this idea that Australopithecus had figured out that bones and teeth were hard and could
27:09be used as weapons to kill other animals.
27:12This sort of killer ape theory of early humans.
27:16Dart believed that the more aggressive of our ape-like ancestors abandoned their forest environments and moved into savannahs.
27:23There they became meat-eating predators.
27:28According to Dart, this transformation into violent killer apes was a key step on the long journey to becoming human.
27:37Dart was a key step on the long journey to become human.
27:43Stanley Kubrick made the killer ape theory frighteningly real at the beginning of his epic film, 2001 A Space Odyssey.
27:58Broken animal bones quickly became weapons for control and conquest.
28:10So will the fossil remains of Sediba back up Raymond Dart's killer ape theory?
28:21Researchers at the Max Planck Institute in Germany hope that Sediba's teeth may tell them more about what these animals
28:28ate.
28:29The tartar that built up around the teeth may contain minute traces of the foods that they were eating.
28:35Well, this is the first time that we've had direct evidence of the kinds of foods that any Australopithe ate.
28:43We've had proxy information before.
28:45We've had sort of vague categories where the food's harder or tougher.
28:50But this is direct evidence. That's exciting.
28:53Trapped in Sediba's tartar are microscopic remains of many different plants.
29:02We have phytoliths from grasses.
29:05We have phytoliths from the bark or woody tissue of plants.
29:10And we have phytoliths possibly from fruits.
29:13So all the evidence suggests that the foods that this individual was eating were coming from closed forested regions.
29:21So eating fruits, maybe chewing on stems, eating the grasses that are growing in that area.
29:28The tooth evidence from Sediba indicates a diet very similar to today's chimpanzees.
29:34While they may have eaten some meat, there's little to back up Raymond Dart's theory that they were killer apes.
29:42Now, the latest discovery at the Rising Star Caves is revealing even more about our transition from ape-like forest
29:50dwellers into the first humans.
29:53And the sheer scale of the find is becoming clear.
29:57Good luck, everyone. Have a blast.
29:59Thank you. Will do.
30:00All right. Go get them. Good luck. Happy hunting.
30:10It was probably a couple hours into the first day when we realized it also wasn't one skeleton.
30:16Another femur.
30:18Femur land.
30:19I remember, right, it started with a second femur from the same size.
30:24And since there's never been a three-legged hominin, we knew there were two.
30:31And then there were three.
30:35I think it was by day two there were four.
30:39And we realized we were in something very, very, very, very, very special.
30:43All right. Good luck with that, Becca. We can't wait to see you.
30:46Initially, Lee had been expecting to find the remains of just one individual.
30:51Now the team saw evidence of many more.
30:54It's everywhere. I mean, it's all strewn all throughout.
30:59Not just the chamber, but the passages leading to it are littered with bone fragments.
31:06By the afternoon of day 14 in the expedition, we were overwhelmed.
31:12I'd started with one safe to hold one skeleton.
31:16Day three, we had two safe. Day four, we had three safe.
31:19Day six, my people were going, we need more safe.
31:26By day 14, as we would get fossil after fossil, we were getting 40, 50, 60, 70 elements a day.
31:35All that was flashing through my mind as I was doing that was that famous scene in Jaws,
31:39where Roy Scheider is chumming and hadn't yet seen the shark.
31:47And he's sitting there chumming, and all of a sudden this gigantic shark appears.
31:53And he goes, we're going to need a bigger boat.
31:59As the fossils accumulate in ever greater numbers,
32:02a picture of the creature of the Rising Star Caves begins to emerge.
32:07This is part of a juvenile pelvis.
32:12Thigh and hip bones tell them it walked upright, but its gait was primitive.
32:20From what they can see of the exposed skull, it's small, not much bigger than a chimp's.
32:27But the teeth and jaws seem more advanced, homo-like.
32:32It's beginning to look as if Lee has found a second new species from the dawn of humanity.
32:42To prove it beyond doubt, they must retrieve a treasure still buried in the cavern below.
32:48The skull will be crucial in telling them whether the creature of Rising Star is Australopith, or homo, human.
32:57We're going to go ahead and bite the bullet and take that skull out, okay?
33:01Yes, yes, yes, yes, good, good.
33:02If only because it gets it out of the way.
33:04Yes, I know.
33:06Not because you want it out, you see it, right?
33:09A couple of reasons we want to get out.
33:10One, the skull can tell you a lot.
33:12It can tell you cranial capacity, you start getting an idea of the shape of the skull.
33:16Is it Australopith-like and pinched in the front, or is it rounded, more like a human, or is it
33:21something in between?
33:23We want to see that skull.
33:27So there was all this tension, and it was a lot harder to extract than we thought.
33:37The skull is extremely fragile.
33:41Every tiny piece of bone has to be carefully retrieved.
33:50Finally, the skull begins its slow ascent, leaving the cave for the first time in possibly millions of years.
34:06And all of those scientists piled back in, all of the people who'd spent so much time and so much
34:13energy coming to this moment, went back in there.
34:17And they lined up in the most difficult places, up the dragon, back to basement, where they knew it was
34:23a risk that it could get damaged. If dropped, it could get destroyed.
34:31Huge tension watching this passage on the cameras until there it was.
34:35There you go, folks. Let's go get it.
34:37Great moment.
34:46It's like a rocky moment. It's like...
34:49Would you hate me if I took this before I hug you?
34:52Please take it.
34:56Oh, well done.
34:57I don't want to argue with that.
35:00It's the moment everyone has been waiting for.
35:04They hope the skull fragment will be the telltale piece to identify the creature as either an Australopith or a
35:12member of our own human genus.
35:16Looking at a left frontal. So it's this part, the orbit, and then part of the brain case just behind
35:26the orbit. And that is a very important piece.
35:31Large orbital ridges with indentations behind them would indicate Australopith.
35:39Smaller brow ridges with evidence of a more rounded skull would say Homo.
35:44We do have our genus.
35:46We do.
35:47We have our genus with that.
35:49This is indisputably Homo.
35:51Yes, yes.
35:55The team's verdict is clear.
35:58They have a new member of our genus.
36:01And deep underground in the rising star chamber, they are about to make a shocking discovery.
36:06About how these ape men might have lived and died.
36:16The rising star excavation has uncovered almost 2,000 bone fragments from more than 12 individuals found in a deep
36:25cave in South Africa.
36:28Now, Lee Berger's team have to piece together and analyze these remains.
36:36The rising star discovery is one of the most startling and amazing discoveries in all of hominid evolution.
36:43To have that many fossils in one place is unprecedented and took everybody by surprise.
36:49As the expedition winds down, the fossils are carefully transported to the University of the Witwatersrand.
36:59At a conference six months after the excavation, researchers meet for an intensive analysis of the recent finds.
37:10The bones from the rising star cave are finally ready to be presented to the world.
37:18We've got a new species of early human in the genus Homo and that's tremendously exciting.
37:24We've never had anything in that transition period between the late Australopis and the earliest members of our genus in
37:33any kind of abundance.
37:34And, boy, we have it in abundance now.
37:40The fossils suggest a creature unlike anything ever found before.
37:45We're looking at creatures that are human-like in their feet, human-like in their hands, human-like in their
37:52teeth.
37:53Everything that interacts directly with the environment is Homo.
37:57And everything that's sort of central, you know, the trunk, the architecture of the vertebral column, the brain, those sorts
38:05of things are more primitive.
38:06It's like evolution is crafting us from the outside in.
38:12The new genus from Rising Star has been given the name Homo naledi.
38:19It's a strange mosaic of ape and human, small-brained and small-bodied, with chimp-like arms, but with human
38:26hands, teeth, small brows and long legs.
38:31Possibly a long-distance walker.
38:34Naledi is a surprise in very many ways.
38:39It's got an incredibly tiny brain, a brain that's more than a third as small as a modern human's brain
38:46is.
38:47Yet it's clear when you look at the cranial shape, the dentition, the legs, particularly the feet and even the
38:54hands, that this thing is part of our genus.
39:03Here are creatures on the cusp of becoming human, but still very close to the Australopith world.
39:15And six months into the analysis of the hidden chamber where they were found, there's a puzzling new twist in
39:21the investigation.
39:23It was pretty surprising that something completely normal to every other excavation I've ever been in wasn't happening here.
39:37We weren't getting anything else other than hominids.
39:45There are no other animal remains in the cave. All the fossils are human ancestors. This is unheard of.
39:55In every other hominid discovery, they are found alongside the bones of other animals that have wandered in and died,
40:03or been dragged there by predators.
40:06They're mixed with antelopes, generally in huge abundance. Then you get, depending on the circumstance, some carnivores and other bits
40:14and pieces and rodents and the stuff that accumulates when things die and are eaten and are dragged into caves.
40:26So how did these hominid bones get into the rising star caves?
40:34The chamber is very inaccessible, deep in the dark zone of the cave, and with no entrance other than the
40:41long, narrow chute.
40:46The team believes it was probably just as inaccessible two million years ago.
40:54It's starting to look as if the bodies might have been intentionally placed there.
41:01Could this possibly be some sort of burial?
41:08At the early stages of this expedition, they look like a cemetery population, very young individuals and very old individuals,
41:14and nothing in the middle so far.
41:16Doesn't mean we're not going to find them. That's what you see in a cemetery when you dig it up.
41:19Right now, it looks a lot like that.
41:22Will it hold out to be that?
41:25That will be a mystery I want to see solved.
41:30Until now, the earliest known burials are from about 100,000 years ago, and a much more advanced form of
41:38early human.
41:40The team does not have an accurate date yet for the fossils of rising star.
41:45But it seems unthinkable that such a primitive looking creature could be disposing of its dead.
41:52It looks like they got in there because somebody put them there.
41:58Now, if we say that, you have to understand that's a very controversial thing to say.
42:04And so we approach it very conservatively.
42:06We can show that there's no signs of predation.
42:10We can show that there's no predator that accumulates only hominins in this way.
42:15We can show that they didn't all get there at once.
42:19We can show that there's not a flow of material into the chamber.
42:23And that's where we leave it, scientifically.
42:25You know, we can say the best hypothesis we can come up with is they were put there.
42:34If this is true, its implications are profound.
42:39The team now know that the rising star hominid had a brain size just slightly larger than a chimpanzee's.
42:50So if, in fact, the rising star hominins are purposefully disposing of their dead,
42:56we're talking about some small-brained hominins who are doing this.
43:00And that begins to change our thinking about sort of the cognitive attributes
43:05and the neural machinery that you need to engage in that kind of behavior.
43:09And that becomes really interesting.
43:13If the skeletons had been intentionally disposed of,
43:17it would indicate highly advanced social behavior
43:21at a much earlier stage in our evolution than had previously been thought possible.
43:28And that here, at the dawn of humanity,
43:31the complex social bonds that mark us out as human
43:34had already begun to take shape.
43:39As yet, the question of exactly how these fossils fit into the story of human evolution is not clear.
43:47The remains from Malapa and rising star may or may not prove to be our direct ancestors,
43:54but they point us towards a new way of thinking about our origins.
43:59We have a strong tendency to want to draw simple lines between species
44:05and make nice family trees.
44:06And we have to understand that that's our need, that's our desire,
44:10that's not necessarily the way that nature works.
44:13Evolution is bushy. There are different experiments.
44:17Populations try different adaptations, they try different ways of being about the world.
44:24Lee's earlier finds and the new Naledi species have a mosaic of Australopith and Homo features.
44:33They seem to show that at the dawn of humanity there were multiple evolutionary experiments
44:39with small-bodied, small-brained, upright walking apes.
44:46Thanks to the work of scientists like Lee Berger, we know some of these varieties of late Australopith and early
44:53Homo existed simultaneously,
44:56and some may have been interbreeding.
45:02So, imagine in your mind a glacier in the top of a valley, and what happens is as it melts,
45:07it creates many, many rivulets,
45:09and some of them are large and some are small, and they all move off down the valley.
45:14And almost inevitably, at the end of that valley is going to be a lake,
45:18of which some, maybe the majority, but not all are contributing to.
45:24I think we have to begin looking at the species we're finding as almost individual channels in a braided stream.
45:33It's clear they have something to do with the end population, and that's us, the billions of human beings alive
45:38today.
45:39But it's hard to tell which one's the most responsible for us being here.
45:47The recent finds on the plains of South Africa are adding a vital new chapter to the story of our
45:54origins.
45:57The tantalizing gap in the fossil record at the beginning of our genus is being slowly filled in.
46:09Finally, there is light at the dawn of humanity.
46:16At eight o'clock next Sunday, secret history follows a breakthrough that could lead to Cleopatra's lost tomb.
46:25An extreme test of loyalty and forgiveness next on four.
46:28Lol can't keep the past suppressed forever.
46:32This is England 90, coming up.
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