You immediately descend into the mouth
of a cave...We suit up, we put harnesses on and we clip into some safety ropes and
then we're climbing this knife edge of rock. It goes about 20 meters up and so
if you were to fall off the Dragons Back that would be very bad. If any of us was
injured on the sort of the far side of the cave, the paramedics would be sent
down to us and you had to live underground until you could get yourself
back out. You go through that little tunnel and then you come out and there
was a more open chamber. But, we only had our headlamps on at that point and so
everywhere we looked you could just see flashes of bone. Hey smart people, Joe here. There may be nearly 8 billion humans on earth, but homo sapiens is a
lonely species. And not just because we stared our phones all day, or never go
outside, or just watch YouTube videos all the time. Because our species is a relict.
The only surviving member of the group of upright Apes known as homo. But it
wasn't always like that. Walk backwards through time and you'll see that at
various points, many other human and hominid species walked the earth.
Some like us and some very different. Everything we know about those ancient species stories we know from fossil bones. And in many cases that means we
don't know very much at all. Which is frustrating because we all want to know where we fit in this story. How did this one species of intelligent ape come to dominate the planet and where do we fit in with all the others.
Well that story just got a whole lot more complicated thanks to a
ridiculously awesome bunch of fossils discovered in South Africa. Over the past
several years, which added a new species to the ancient human family. For the
first time ever, these fossils travelled outside South Africa to Dallas, Texas. So
I stopped by the Perot Museum of Nature and Science to check them out and meet
the scientists who discovered them... and to take a selfie with my ancient cousin.
We'll get to that. How many people have found new human species like ever?
Probably a dozen maybe, maybe 15. And you found two! Yes! Paleoanthropologist Lee Berger lives and works in South Africa
searching for ancient human fossils. Scientists have been digging up human
fossils in this area for decades but thanks to new technology and satellite
imagery, in 2013, Lee had identified a few spots he
thought others might have missed. Expert cavers on Lee's team had discovered an
unexplored section and what's known as the Rising Star cave system. They named
it the Dinaledi Chamber, meaning chamber of stars in one of the local
South African languages. When they descended to the bottom of that chamber
they did find something bright shining back at them; fossil bones, piles of them.
When Lee saw pictures of the fossils in the chamber, he immediately knew they
were fossils of an ancient human relative. Problem was that he was too big
to fit inside the cave to study them so he did what any of us would do. He put
out a Facebook post asking for help: "Volunteers needed. Excellent
archaeological paleontological and excavation skills, they must be skinny
and preferably small and they must not be claustrophobic." I mean, who wouldn't
respond to that. They were looking for archaeologists with caving and climbing
experience and before I started studying archaeology, I was doing outdoor
leadership. So it sort of sounded like me, but I didn't really expect to hear anything.
But pretty soon I was underground! My supervisor sent me the ad and said, "Hey
you have climbing experience. Don't you" have caving experience, too?" I said well
yes and so it sounded bizarre and bizarre enough that I would want to do
it. Becca Peixotto and Marina Elliott are two members of the six scientists team
who descended into the cave to unearth these fossils and bring them to the
surface to study. Excavating these fossils required what was essentially a
military-level operation. Kilometers worth of cables were strung so Lee and
others in a command tent on the surface could watch every moment of the
excavation and communicate with the team underground. We got dubbed the underground astronauts. And the people who were on the surface
who couldn't come underground with us we're watching us on these sort of
grainy CCTV cameras and it reminded them of watching astronauts, you know working
on spacewalks in the space station. To say that it wasn't easy for them to get
to work every day would be a bit of an understatement. We have to
travel through this cave where the narrowest point that we have to get
through is 18 centimeters wide. You have to get down on your belly and sort of do
a belly crawl to get through it. It's called the Superman crawl because folks
with broader shoulders have to put one hand over their head, and
sort of push themselves along with their feet sort of flying like Superman. You
come out from under the Superman crawl and you can stand up and you're in a pretty
big chamber and that's where the base of the Dragons Back is. Yeah, and then we end up in an area called the top of the chute and the chute is actually a long
crack or fissure in the dolostone, or in the rock.
meters high. At its widest, it's And it's about 45 centimeters. At its
narrowest it's that 18 centimeters. 18 centimeters is like the size of my head - it's just not possible. I have a big head.
See if I've got what it takes to join the underground astronaut squad. As they brought the fossils to the surface, and began to look at their features, they
began to realize they had found something very strange. For one thing it
was a totally new species. They named it Homo naledi. And this wasn't just one
individual. This cave held many individuals, like plural. In that first
2013 expedition we brought up..whatever it was 1350 fossil fragments which in
itself is is crazy. But they all came from a single excavation unit 80
centimeters by 80 centimeters by 20 centimeters deep. And we found bones
representing, I think we're up to 22 individuals now. All of the body parts
are represented, so there's foot bones and hand bones and rib bones and
vertebra and teeth and all of it. The Rising Star site, the Dinaledi Chamber,
the Lesedi Chamber, and other areas around there, we've discovered more
individual hominid remains than the entire record of hominin evolution from
the continent of Africa. I think our field had convinced itself
there was nothing left to find, and people stopped looking. This is a message
that there's more out there, and there's not just a little bit more there's a lot
more. Okay now I don't know how you think
fossil hunting works especially the search for ancient human, but that is not
how this usually goes. When people find hominid fossils, you're finding part of a
jaw, you're finding some teeth, maybe you're finding just one little digit
from a hand and that's how species are described. So there are whole species
that are known from just really small parts of the body. Whereas, with Homo
naledi, we have the whole body from a bunch of different individuals several
times over. Homo naledi's bones don't look like the bones of other
ancient humans or hominids. At least they don't look like anything we've ever seen
together in one single species. So we're behind the scenes in the Perot museum and
we're just going to go in and have a peek at an at a reconstruction of Neo.
So what those bones might have looked like in life. And this is our buddy Neo
here. So Homo Naledi has a sort of mosaic of features. Some aspects of Homo naledi
look a lot like our bodies and some aspects look a lot like our more ancient
relatives. So they have a really tiny brain. If you can look at the cranium
here. So they have a brain that's roughly the size of an orange. But when we take
endocasts, molds, of the inside of the skull, we can see that the brain has
a lot of similar features (in terms of the sort of waves and folds on the
outside of the brain) as ours do. So that indicates that you know while they have
a tiny brain they maybe had a brain that had a lot of functions. So jaws are
always cool. In part because everybody knows what their own teeth look like. And
so you can see that Neo's teeth actually don't look that dissimilar from our own.
And we've of course found complete hands of Naledi . It becomes more and more
human-like. And so the wrist and hand proportions
are almost completely human-like except for two things; One the thumb. The thumb
is utterly unique. It's extremely long. And the fingers are curved. It's curved
as the most ancient hominids that we have. So that would make sense if this
was alive two million years ago. Absolutely! 3 million years ago. But it
wasn't. When we first started looking at the anatomy, I think a lot of people
thought "Oh this thing has to be at least a million, maybe two million years old."
Some of the teeth were tested using a technique called electron spin resonance.
So that was one way we were able to figure out that Naledi was in this three
hundred thousand years ago range. It really was surprising to find out that Naledi
was as young as it was in the timeframe that Homo naledi is. Anatomically modern
humans were also on the African landscape. Modern, primitive, and different at all once.
As of today, the team has recovered fossils from at least 20 individuals
from Dinaledi and a nearby chamber. That brings up a huge question - "How did
all these bones get in this cave?" Our hypothesis is that Homo naledi were
deliberately disposing of their dead. So we think that Homo naledis were
dying on the surface and their fellows were bringing the dead ones down into
this cave system. We don't know why because we don't have any evidence for
that and we unfortunately can't ask Neo. He's not too talkative. Deliberate body
disposal was one of those behaviors, those rituals, one of the few things that
only our species did that made us unique. And this shatters that idea. It's another
in a long list of things that we used to think of as uniquely part of our species
that aren't. Up until Jane Goodall saw chimpanzees actually termite fishing, boy
that was our gig. You could look at us and you said, "Wow we do tools no one does." Okay, cross tools off the list. Art; We now know that other
animals do complex ornamentation and decoration. Birds do a great job of that, right? We know other animals mourn now. We know that they grieve over their dead.
They interact with death in a different way and many different species do that.
So, we've lost that. And then there's this last thing though that we had. You know,
this idea of recognition of self mortality, deliberate body disposal. The
idea that we deal with our dead. And the reason that we thought we did that is
because we saw ourselves as separate from nature. We saw ourselves as a
creature that was different from other animals and therefore we wouldn't
allow any of our individuals to undergo those processes. If that hypothesis holds
here for these specimens in these many different places
that we find them now. Then you're looking at a creature that shared that.
For me, I often talk about humans and other animals. because we are animals. And I think when we think about ourselves as being part of the animal kingdom, I think
that, to me, that helps us bring ourselves back into being you know
co-inhabitants of this planet. This whole story leads up to some big questions.
Where does Homo naledi fit into our story? Is it our ancestor? Is it something
else? Well, the answer isn't simple. We're all familiar with this version of human
evolution. A primitive looking thing giving rise to a slightly less primitive
thing giving rise to another and another and finally something like us - something
advanced . A march of progress. Well, that isn't how evolution works. And Homo
naledi is proof of that. I think this model of the braided stream helps us get
over that hurdle of thinking that you know one species and then the next
generation is born and it's another species, but that evolution happens
gradually and through multiple mechanisms through time. The idea that
that we were this inevitable walk to be this in humans or this successful
dominant thing - we've hardly been tested yet. Yeah, you take it air conditioning
and delivery food away and we're in trouble. Absolutely! Thanks to fossils like Homo naledi, we
know that the human story played out like a tangled braided stream.We're at
the end of one branch near the end. But we're not the only branch, and along the
way, back through time, branches have split off to fade out or perhaps even
join back with others and combine again. It isn't a tree that grows up and some
march towards some ideal best species. It trickles out simply forward in time
following the landscape carved out by natural selection.
We're just along for the ride, looking back and trying to figure out where
we've come from and who our fellow travelers were along
the way. Stay curious. I want to give a special thanks to the Perot Museum of Nature and Science in Dallas Texas for inviting me up to see these fossils in
person and meet the scientists. This is the first and probably the only time
these fossils will be outside of South Africa and I'm just really honored that
I got to be next to them and experience this. They even gave them South African
passports. Are you kidding me! They'll be on display through early 2020
as part of an exhibit at the museum called Origins. So if you're watching
this before then and you find yourself in Dallas, go check them out. They aren't
paying me to say that...just an awesome thing and you should know about it.
There's links down in the description and I'll probably have some more to show
you from my visit in a few weeks, so stay tuned. And thanks to everyone who
supports the show on Patreon. You are awesome! And thanks to you, I get to go
see cool stuff like this and share it with everyone. If you want to join our
family go check out the Patreon page. We've got a lot of cool perks at
different levels and you can even join the ranks of these Galaxy Brain
supporters.
Very cool report! Love seeing anthro-archeology get to the masses. Love the note on making the field realize that we are still scratching the surface on discoveries.
this is really impressive! thanks for sharing it
interesting video
I honestly don't believe they were burying their dead. How would you even pull a corpse through that tiny opening? I think it's more likely that every now and again one of them would just get curious and climb into the cave but not be able to climb back out and starve to death. Its would explain why none of them had signs of injuries causing their death.