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66 million years ago,
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Planet Earth was very different
from today.
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Back then, one of our closest
ancestors might have looked
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00:00:24,040 --> 00:00:27,480
something like
this little furry creature.
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RUMBLING GROWL
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The rulers of the land
were giant reptiles.
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Dinosaurs.
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That's one of the most infamous,
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a carnivorous T-rex.
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And just behind are
the bison of their time,
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a common plant-eater,
Edmontosaurus.
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But what happened to them all?
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66 million years ago,
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an asteroid hit the Earth,
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and scientists think
that it was this collision
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that wiped out the dinosaurs.
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But no-one has ever found
direct evidence of that.
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In fact, no-one has ever found
the fossil of a dinosaur
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that died within
a thousand years of the impact.
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However, a remarkable dig site
promises to change that.
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It's in the Hell Creek formation
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in the American Midwest.
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These badlands are rich
in prehistoric remains...
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ROARS
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..from triceratops...
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SQUAWKS
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..to pterosaurs.
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And here, one patch of land
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about the size of a football pitch
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is yielding a collection
of astonishing fossils.
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The precise location is
a closely guarded secret,
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because this place
may hold evidence...
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..of one of the most dramatic events
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in all the four-and-a-half-
billion-year history
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of our planet.
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Right, let me get down here
between you.
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For ten years,
a palaeontologist and his team
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have been trying to find out
exactly what happened here.
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You're at the edge
of your seat every moment,
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trying to dig this stuff up.
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It's like trying to defuse
a nuclear weapon
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while you're in a rainstorm.
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He's named the site Tanis,
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and believes it could be
a mass graveyard
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of creatures that were killed
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in the catastrophic asteroid strike.
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A site that could reveal not only
how the last dinosaurs lived,
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but how they died.
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If the dig team is right,
Tanis could be a place
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where the remains
of a long-lost world
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are frozen in time.
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A place that gives us,
for the first time,
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an unprecedented window...
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SHRIEKS
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..into the lives
of the very last dinosaurs...
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..and a minute-by-minute
picture of what happened
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on the day the asteroid hit.
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This landscape is full of fossils
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dating from the Late Cretaceous,
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the period which began
around 100 million years ago
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and ended 66 million years ago,
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when the dinosaurs vanished.
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Palaeontologist Robert DePalma
wants to find out more.
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I think anybody
who's ever liked dinosaurs
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in the past, or still does,
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has thought at one point
or another,
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"Well, what happened to them?
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"Why are they not here
any more?"
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So many different theories
are out there,
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and nobody has a tight answer
to that question.
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Judging from fossil evidence,
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this is what Hell Creek looked
like in the Late Cretaceous.
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There were low-lying,
marshy flood plains,
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intercut by river channels
and covered with horsetails,
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ferns and trees.
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Back then, it was warm
and wet here all year round.
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Tanis lies
in the north-eastern corner
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of the Hell Creek formation.
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Instead of today's
dusty prairies,
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there were sandy river banks.
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00:05:45,080 --> 00:05:48,640
Instead of rocky cliffs,
there were forests.
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And instead
of the life we know today...
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DEEP RUMBLING CALLS
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TRILLING
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..well, Robert is hoping
to find out more
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about what that was like.
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COOING
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A sandbank lying between
a river and a forest
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would one day become
what Robert now calls Tanis.
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He and his team have been
digging here since 2012.
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So somewhere from between there
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00:06:26,360 --> 00:06:28,040
and down here
is where that came from.
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It's come from up above.
Hey, look at this.
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What? Look.
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Oh, yeah, yeah, yeah. OK.
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00:06:32,720 --> 00:06:36,240
And what they found is unexpected.
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Here we've got
this freshwater environment
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of the Hell Creek formation,
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and these shocking
red, green colours
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coming from the shells of ammonites,
a marine organism,
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kind of like a coiled snail
in appearance.
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So we've got this marine organism
that's been thrown up
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into this freshwater environment,
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and they do not belong here.
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How they got here is a mystery.
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OK...
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And there's more.
108
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I'm just going to go ahead and
plane down some of this rock.
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Sitting just above the ammonites
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is something that
many dinosaur hunters
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are desperate to find.
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So this orange layer right here
is composed 100%
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of impact-related debris
that is enriched in iridium.
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Iridium is an element that's rare
in the Earth's crust,
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but it's common in asteroids.
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The layer it's in is called
the K-Pg boundary.
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Dear Momma...
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Oh, dear. Really?
Yeah.
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It's made up of dust and debris
from a huge asteroid impact.
120
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Look at that. That's amazing.
121
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Yeah, yeah, yeah, yeah, yeah.
That's what we want.
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OK. So it's coming
from this area here.
123
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So somewhere within that region is
where these pieces are coming from.
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The boundary separates
the age of the dinosaurs
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from the age of mammals,
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so the rocks here
come from about the time
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that the dinosaurs became extinct.
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No rattlesnakes.
129
00:08:07,520 --> 00:08:10,360
What makes the site even
more exciting
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is the rock layer
right beneath the boundary
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where Robert found the ammonites.
132
00:08:15,160 --> 00:08:17,840
The rock here
is really not quite rocky,
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as you would expect dinosaur bones
and things to be encased -
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00:08:20,480 --> 00:08:23,000
you expect really, really hard
rocks and jackhammers
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00:08:23,000 --> 00:08:25,640
and things like this,
but it's very, very crumbly
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and it just falls apart
in your hands.
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As well as being crumbly
throughout,
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00:08:31,760 --> 00:08:35,480
this layer of rock is also
around a metre thick,
139
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which, along with
other unusual features, makes
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00:08:38,760 --> 00:08:43,880
Robert think that something very
strange must have happened here.
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Maybe a flood or a mud flow,
142
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burying anything within it
in an instant.
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00:08:53,880 --> 00:08:57,160
Oh, there's a beautiful...
Look at that one - beautiful.
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This could mean that anything
he finds in this layer
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would have been quickly entombed,
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like the bodies in
the volcanic ash of Pompeii.
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Robert knows from the geology
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that anything he finds at Tanis
will be tantalisingly close
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to the end
of the age of the dinosaurs
150
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and could be so well preserved
151
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that it could reveal new evidence
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that will bring this time period
to life
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in a way
no-one has ever done before.
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Robert digs at Tanis each summer,
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the only time the weather
allows him to do so.
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Come on down,
check out this lens over here.
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In order to understand how the
impact affected life on Earth,
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you really need to get
a very clear picture
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of what the world was like
right before.
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That is a critical part
of the story.
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Palaeontologists Dr David Burnham
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and Loren Gurche have been
digging with Robert for years.
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Oh, wow!
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See...see the brown? Yep.
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That might be a tubercle
right there.
166
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And it seems today is their
lucky day.
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Oh, my God! Look at that!
Look at that.
168
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Look, the scales are preserved!
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Holy crap! Like doing
a freaking dissection.
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Oh, my God. Biology of Tanis.
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Oh, the scale...
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Look, look - the wrinkles
continue down that way.
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Mine's all nice and wet so far.
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The scales are getting smaller
in that direction.
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How big are they there?
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I got a...I got one with
the projection over here.
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What? Oh!
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Yeah. Oh.
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Yeah, there's the protuberance
right there.
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I've only seen that on one other
specimen, in life. Yep.
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This is the closest thing
to getting to touch
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a living, breathing dinosaur.
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It is.
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They found something extraordinary.
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It is so exceedingly rare -
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a piece of triceratops skin
in the Hell Creek formation.
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It may look like
an impression in the rock,
188
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but this is skin
that has been fossilised
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and, over millions of years,
has turned to stone.
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Triceratops bones are relatively
common finds in Hell Creek,
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but skin in such condition as this
is very rare indeed.
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The size and the patterning
of the scales,
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together with the age
and location of the rocks
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where it was found,
strongly suggests
195
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that this is
from a triceratops.
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The brown colour contains
traces of organic material.
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So it might even be possible
from this
198
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to work out
which pigments were in it.
199
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Finding and studying
200
00:11:53,120 --> 00:11:55,520
such well-preserved fossils
as this
201
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helps palaeontologists build
202
00:11:57,440 --> 00:12:01,280
a much more detailed picture
of how these creatures lived.
203
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Combining this information
204
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with insights from scientists
around the world
205
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makes it possible to speculate
206
00:12:10,000 --> 00:12:12,080
about what life
in the Late Cretaceous
207
00:12:12,080 --> 00:12:14,080
might have been like.
208
00:12:22,520 --> 00:12:23,960
We know from bones
209
00:12:23,960 --> 00:12:27,720
that adult triceratops could
reach nine metres in length
210
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and three metres in height.
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RUMBLING
212
00:12:33,960 --> 00:12:36,080
Marks on the fossil also show us
213
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that this one was badly scarred.
214
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RUMBLING GROWL
215
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Triceratops were plant-eaters.
216
00:12:55,680 --> 00:12:58,680
Other fossils tell us
that they had sharp beaks
217
00:12:58,680 --> 00:13:02,680
and hundreds of teeth that enabled
them to shred tough plants
218
00:13:02,680 --> 00:13:04,560
such as these cycads.
219
00:13:13,000 --> 00:13:14,400
DISTANT TRUMPETING
220
00:13:14,400 --> 00:13:17,400
Almost all adult
triceratops fossils,
221
00:13:17,400 --> 00:13:20,640
including Robert's,
have been found on their own.
222
00:13:22,240 --> 00:13:25,200
So it's possible
that the adults were solitary,
223
00:13:25,200 --> 00:13:27,760
like modern-day male rhinos.
224
00:13:29,920 --> 00:13:32,160
So they were
probably territorial,
225
00:13:32,160 --> 00:13:34,400
chasing rivals away.
226
00:13:40,640 --> 00:13:43,280
And perhaps
marking their territories.
227
00:13:48,720 --> 00:13:51,040
If you weigh more
than an African elephant,
228
00:13:51,040 --> 00:13:53,120
there's not much
that can bother you...
229
00:13:54,240 --> 00:13:55,720
SQUEAKING
230
00:13:57,720 --> 00:14:00,800
..except perhaps a little mammal.
231
00:14:03,280 --> 00:14:07,560
GROWLS
232
00:14:17,320 --> 00:14:20,200
Robert found these jawbones
233
00:14:20,200 --> 00:14:23,600
in the fossilised burrow at Tanis.
234
00:14:23,600 --> 00:14:26,840
The shape of this tiny bone
and tooth
235
00:14:26,840 --> 00:14:30,160
means it's most likely come
from what's known
236
00:14:30,160 --> 00:14:33,240
as a pediomyid, an early mammal
237
00:14:33,240 --> 00:14:36,240
and a type of marsupial.
238
00:14:39,640 --> 00:14:42,960
Robert also discovered
fossilised nuts and seeds
239
00:14:42,960 --> 00:14:44,240
in the burrow.
240
00:14:45,560 --> 00:14:48,600
So we have an idea about
what it might have eaten.
241
00:14:48,600 --> 00:14:50,240
DISTANT TRUMPETING
242
00:14:56,320 --> 00:14:58,240
Robert's finds are adding
243
00:14:58,240 --> 00:15:00,720
to our knowledge
of the complex world
244
00:15:00,720 --> 00:15:03,840
at the very end
of the Late Cretaceous.
245
00:15:03,840 --> 00:15:07,280
And it's not just
the fossilised creatures.
246
00:15:07,280 --> 00:15:09,920
If you walk on damp sand,
247
00:15:09,920 --> 00:15:11,960
you'll leave a trace behind.
248
00:15:16,240 --> 00:15:17,280
A footprint.
249
00:15:18,680 --> 00:15:23,040
The same was true
66 million years ago.
250
00:15:23,040 --> 00:15:27,520
And very, very occasionally,
such traces were preserved.
251
00:15:27,520 --> 00:15:31,120
And that's exactly
what happened here at Tanis.
252
00:15:33,280 --> 00:15:35,640
You know, we won't foil a backside.
253
00:15:35,640 --> 00:15:37,720
Right, we'll just put...
Put plaster right on.
254
00:15:37,720 --> 00:15:38,880
That way you've got...
255
00:15:38,880 --> 00:15:41,400
Robert has discovered
a number of footprints.
256
00:15:41,400 --> 00:15:43,320
Yeah. Let's see.
257
00:15:43,320 --> 00:15:45,640
Looks like a good print. Yeah.
258
00:15:50,080 --> 00:15:52,680
Their shape gives him a clue
259
00:15:52,680 --> 00:15:55,280
as to what might have made them.
260
00:16:00,280 --> 00:16:01,600
If he's right,
261
00:16:01,600 --> 00:16:04,040
they were made by a winged creature,
262
00:16:04,040 --> 00:16:07,080
that might well have liked
a small mammal...
263
00:16:09,880 --> 00:16:11,080
..for lunch.
264
00:16:18,160 --> 00:16:20,640
The footprints are long and narrow
265
00:16:20,640 --> 00:16:22,200
with four toe prints.
266
00:16:23,600 --> 00:16:26,800
Two are slightly longer
than the others,
267
00:16:26,800 --> 00:16:29,760
and that suggests
they were made by...
268
00:16:32,400 --> 00:16:33,800
..a pterosaur.
269
00:16:33,800 --> 00:16:35,320
SQUAWKS
270
00:16:43,040 --> 00:16:47,200
Pterosaurs are not dinosaurs,
but flying reptiles
271
00:16:47,200 --> 00:16:50,240
on a different branch
of the evolutionary tree.
272
00:16:57,560 --> 00:16:59,160
SCREECHING
273
00:17:04,560 --> 00:17:07,200
Male pterosaurs
usually had crests,
274
00:17:07,200 --> 00:17:09,000
while females didn't.
275
00:17:09,000 --> 00:17:12,600
So crests may have been
used in courtship displays.
276
00:17:18,920 --> 00:17:20,360
SHRIEKS
277
00:17:22,160 --> 00:17:26,200
And we have an indication of
where females laid their eggs,
278
00:17:26,200 --> 00:17:30,120
because evidence suggests
one pterosaur laid hers
279
00:17:30,120 --> 00:17:33,840
in the soft, sandy banks
of the river at Tanis.
280
00:17:49,080 --> 00:17:52,040
And this is a fossilised egg
281
00:17:52,040 --> 00:17:54,960
of a pterosaur
that Robert found there.
282
00:17:56,400 --> 00:17:59,760
The only one ever discovered
in North America.
283
00:17:59,760 --> 00:18:02,160
If you look at it
with the naked eye,
284
00:18:02,160 --> 00:18:06,200
all you see
is a jumble of lines.
285
00:18:06,200 --> 00:18:09,200
But if you examine it
with the latest technology,
286
00:18:09,200 --> 00:18:13,280
you can find out
a wealth of information,
287
00:18:13,280 --> 00:18:15,480
from the chemistry of the bones
288
00:18:15,480 --> 00:18:17,480
to the composition of the shell.
289
00:18:17,480 --> 00:18:20,360
And that, in turn,
can tell us a lot about
290
00:18:20,360 --> 00:18:23,200
how these incredible creatures
lived.
291
00:18:29,200 --> 00:18:31,160
Robert has been given access
292
00:18:31,160 --> 00:18:35,200
to the Diamond Light Source
synchrotron in Oxfordshire.
293
00:18:36,920 --> 00:18:39,080
It's a very powerful research tool
294
00:18:39,080 --> 00:18:41,160
that acts like a giant microscope.
295
00:18:44,280 --> 00:18:47,960
By accelerating electrons
in this huge ring,
296
00:18:47,960 --> 00:18:50,040
the synchrotron creates
beams of light
297
00:18:50,040 --> 00:18:52,560
many times brighter than the sun.
298
00:18:59,160 --> 00:19:03,440
Robert and paleobiologist
Dr Victoria Egerton
299
00:19:03,440 --> 00:19:06,480
now want to turn that beam
onto the egg fossil
300
00:19:06,480 --> 00:19:09,920
to discover more
about its chemical make-up.
301
00:19:09,920 --> 00:19:12,560
We're pretty much lined up
on the skeleton,
302
00:19:12,560 --> 00:19:14,440
but we might have to move
the stage a little bit
303
00:19:14,440 --> 00:19:17,320
to get to the right part. Sure.
304
00:19:17,320 --> 00:19:22,400
Meanwhile, Robert can reveal
the creature inside.
305
00:19:22,400 --> 00:19:24,520
And this?
306
00:19:24,520 --> 00:19:27,760
Who made this wonderful thing?
307
00:19:27,760 --> 00:19:31,080
I got replicas of the bones
from inside that egg
308
00:19:31,080 --> 00:19:33,520
and I restored the remainder
309
00:19:33,520 --> 00:19:34,560
and put together
310
00:19:34,560 --> 00:19:36,920
what the skeleton would've
looked like when it hatched.
311
00:19:36,920 --> 00:19:39,000
That's how big the creature
would've been
312
00:19:39,000 --> 00:19:40,440
outside the egg, if it had hatched.
313
00:19:40,440 --> 00:19:45,440
So this is the baby.
How big was it going to grow?
314
00:19:45,440 --> 00:19:48,160
These very long neck vertebrae
here
315
00:19:48,160 --> 00:19:51,320
are what really gave part
of the story away to us,
316
00:19:51,320 --> 00:19:53,840
because those long bones
match very, very closely
317
00:19:53,840 --> 00:19:55,480
with the azhdarchid pterosaurs.
318
00:19:55,480 --> 00:19:57,160
That is the giant pterosaurs.
319
00:19:57,160 --> 00:19:59,280
Oh, they were the whoppers,
weren't they?
320
00:19:59,280 --> 00:20:02,360
I mean, what, 25 feet?
321
00:20:02,360 --> 00:20:03,880
Wingspan? Some of them.
322
00:20:03,880 --> 00:20:08,240
This probably had a wingspan,
maybe 15 feet, five metres.
323
00:20:08,240 --> 00:20:11,000
Well, it looks as though
it could take off, really.
324
00:20:11,000 --> 00:20:13,000
It's easy to picture
something like that
325
00:20:13,000 --> 00:20:15,160
just hatching out of the egg
and fluttering out,
326
00:20:15,160 --> 00:20:17,000
almost like a little bat.
327
00:20:21,880 --> 00:20:26,360
They've scanned the egg,
here and in America.
328
00:20:28,120 --> 00:20:30,640
Victoria has the results.
329
00:20:32,480 --> 00:20:35,720
So what have you learned
from the synchrotron image?
330
00:20:35,720 --> 00:20:38,120
What we have here is a chemical map
331
00:20:38,120 --> 00:20:41,960
of calcium directly within
the bones of this animal.
332
00:20:41,960 --> 00:20:46,080
That tells us that these bones
were already hardened.
333
00:20:46,080 --> 00:20:49,880
So it might be ready to fly
not long after it hatches.
334
00:20:49,880 --> 00:20:52,440
OK. Can you see any sign
of the shell,
335
00:20:52,440 --> 00:20:53,840
and what sort of shell was it?
336
00:20:53,840 --> 00:20:57,120
We can. What I can show you...
337
00:20:57,120 --> 00:20:58,520
Ah!
338
00:20:58,520 --> 00:21:01,600
..is we can see the rim
of the egg in sulphur.
339
00:21:01,600 --> 00:21:06,560
Does that tell you whether it was
a hard shell or a soft shell?
340
00:21:06,560 --> 00:21:08,160
We have been looking at this.
341
00:21:08,160 --> 00:21:13,360
We can see folding occurring,
and this unusual undulation.
342
00:21:13,360 --> 00:21:15,160
If it were a hard egg,
343
00:21:15,160 --> 00:21:18,080
we would expect splintered bits
and broken bits,
344
00:21:18,080 --> 00:21:20,200
just like a chicken egg.
345
00:21:20,200 --> 00:21:22,000
This helped to tell us
that it was soft.
346
00:21:22,000 --> 00:21:24,200
So it was perhaps like a turtle?
347
00:21:24,200 --> 00:21:25,520
Absolutely.
348
00:21:25,520 --> 00:21:28,040
That's not the case, is it,
with dinosaurs?
349
00:21:28,040 --> 00:21:31,120
Many dinosaurs laid
hard-shelled eggs. Yes.
350
00:21:31,120 --> 00:21:34,400
So this is a new discovery
about azhdarchid pterosaurs?
351
00:21:34,400 --> 00:21:36,760
Absolutely. This is something
352
00:21:36,760 --> 00:21:39,000
that we are confirming
for the first time.
353
00:21:39,000 --> 00:21:40,360
Huh!
354
00:21:40,360 --> 00:21:43,640
That flying pterosaurs
had eggs like turtles.
355
00:21:43,640 --> 00:21:44,720
Yes.
356
00:21:44,720 --> 00:21:47,360
Much more reptilianlike
than birdlike.
357
00:21:47,360 --> 00:21:49,720
And that can potentially
tell us more
358
00:21:49,720 --> 00:21:53,120
about the environment
in which these eggs were laid.
359
00:21:53,120 --> 00:21:54,920
How interesting. Yeah.
360
00:22:03,240 --> 00:22:07,160
Creatures that lay soft eggs
tend to bury them
361
00:22:07,160 --> 00:22:08,800
in order to protect them.
362
00:22:10,640 --> 00:22:12,440
SQUAWKS
363
00:22:14,480 --> 00:22:17,040
So female pterosaurs
probably looked for
364
00:22:17,040 --> 00:22:20,280
places like Tanis
to lay their eggs...
365
00:22:22,960 --> 00:22:27,000
..because the sandy soil here
is just soft enough
366
00:22:27,000 --> 00:22:30,200
for the hatchling to dig itself out.
367
00:22:30,200 --> 00:22:31,960
SNIFFING
368
00:22:31,960 --> 00:22:35,480
Now the pterosaur
just has to make sure
369
00:22:35,480 --> 00:22:37,040
that the hole...
370
00:22:38,560 --> 00:22:40,040
..is perfect.
371
00:22:44,520 --> 00:22:45,880
SQUAWKS
372
00:22:50,280 --> 00:22:52,320
WARBLING
373
00:22:56,640 --> 00:22:58,200
Success!
374
00:22:59,680 --> 00:23:02,080
But it's not over yet.
375
00:23:02,080 --> 00:23:05,520
Pterosaurs had two ovaries,
376
00:23:05,520 --> 00:23:08,240
and they laid their eggs in pairs.
377
00:23:18,000 --> 00:23:20,040
Here on the sandbank,
378
00:23:20,040 --> 00:23:24,240
sandwiched between the river
and these glorious trees,
379
00:23:24,240 --> 00:23:27,240
life at Tanis
seemed to be thriving.
380
00:23:27,240 --> 00:23:29,240
GASPS
381
00:23:27,240 --> 00:23:29,240
Whoops!
382
00:23:29,240 --> 00:23:31,160
Never a dull moment.
383
00:23:31,160 --> 00:23:34,200
But all that was about to change.
384
00:23:41,520 --> 00:23:44,840
The chain of events that led to the
extinction of the dinosaurs
385
00:23:44,840 --> 00:23:49,960
began in the distant past,
deep in space.
386
00:23:54,400 --> 00:23:58,520
Most scientists think it all started
in a ring of dust,
387
00:23:58,520 --> 00:24:02,280
rocks, and debris
known as the asteroid belt.
388
00:24:05,520 --> 00:24:08,000
It's usually an uneventful place.
389
00:24:11,920 --> 00:24:15,080
But it's thought that many,
many millions of years ago,
390
00:24:15,080 --> 00:24:18,240
a rock was bumped
into a new orbit...
391
00:24:22,760 --> 00:24:26,720
..and diverted onto a collision
course with Planet Earth.
392
00:24:39,400 --> 00:24:42,200
Robert is building a vivid picture
393
00:24:42,200 --> 00:24:44,440
of Late Cretaceous life
at Tanis.
394
00:24:47,120 --> 00:24:50,840
And the team have found some more
well-preserved footprints.
395
00:24:52,160 --> 00:24:55,520
So these are animals that were
actually walking in the water?
396
00:24:55,520 --> 00:24:57,560
These guys would've been
essentially on
397
00:24:57,560 --> 00:24:59,080
a mushy river bank going down
398
00:24:59,080 --> 00:25:00,800
to drink at some point.
399
00:25:00,800 --> 00:25:03,960
You know, animals tend to
congregate around the rivers.
400
00:25:03,960 --> 00:25:06,680
This print is 30 centimetres long.
401
00:25:07,880 --> 00:25:10,240
So I think this is from
a type of dinosaur
402
00:25:10,240 --> 00:25:12,160
that we call a duck-billed dinosaur.
403
00:25:12,160 --> 00:25:15,800
And they would've been
very common in the Cretaceous.
404
00:25:15,800 --> 00:25:18,120
They ate the plants in the area
405
00:25:18,120 --> 00:25:20,640
and they got very large -
30 feet long.
406
00:25:22,280 --> 00:25:23,840
And there are more.
407
00:25:23,840 --> 00:25:27,600
This track, you see all the toes
are very well preserved.
408
00:25:27,600 --> 00:25:30,680
You even see a nail print
at the tips of the toes.
409
00:25:30,680 --> 00:25:33,000
So the little toenails
dug into the mud.
410
00:25:33,000 --> 00:25:34,240
I love this one.
411
00:25:38,960 --> 00:25:42,120
This is Robert's prized footprint.
412
00:25:42,120 --> 00:25:45,040
It has three toes,
413
00:25:45,040 --> 00:25:48,560
and it's longer than it is wide.
414
00:25:48,560 --> 00:25:53,160
So it's very likely to be
a carnivorous dinosaur.
415
00:25:53,160 --> 00:25:55,680
It's so well preserved
that you can see
416
00:25:55,680 --> 00:25:59,240
the mark left by
its sharp claw there.
417
00:26:00,480 --> 00:26:02,040
Hell Creek is well known
418
00:26:02,040 --> 00:26:05,960
for one carnivore in particular -
T-rex.
419
00:26:07,040 --> 00:26:11,480
This footprint is too small
for an adult T-rex,
420
00:26:11,480 --> 00:26:15,480
but it's possible that it was made
by a young one.
421
00:26:25,560 --> 00:26:29,320
Robert also found this at Tanis -
422
00:26:29,320 --> 00:26:31,800
the crown of a tooth.
423
00:26:31,800 --> 00:26:35,800
Its shape and its serrated edge
424
00:26:35,800 --> 00:26:38,200
are indications that it comes
425
00:26:38,200 --> 00:26:39,960
from an adult T-rex.
426
00:26:44,400 --> 00:26:46,400
RUMBLING GROWL
427
00:26:53,240 --> 00:26:58,360
DEEP RUMBLING GROWL
428
00:27:01,720 --> 00:27:03,760
GROWLS
429
00:27:05,360 --> 00:27:08,000
Bite marks found on T-rex bones
430
00:27:08,000 --> 00:27:11,000
show that they ate other T-rexes.
431
00:27:12,640 --> 00:27:15,320
And a youngster
would make an easy catch.
432
00:27:15,320 --> 00:27:17,360
SNEEZES
433
00:27:20,840 --> 00:27:22,680
But not this time.
434
00:27:32,040 --> 00:27:35,320
Very few footprints
are preserved as fossils
435
00:27:35,320 --> 00:27:37,200
in Hell Creek.
436
00:27:37,200 --> 00:27:39,520
So if you find several
in one place,
437
00:27:39,520 --> 00:27:41,160
as Robert has done,
438
00:27:41,160 --> 00:27:42,720
it's a reasonable assumption
439
00:27:42,720 --> 00:27:46,120
that there would've been
many more nearby.
440
00:27:49,440 --> 00:27:52,160
And that supports the idea
441
00:27:52,160 --> 00:27:56,880
that dinosaurs and pterosaurs
were thriving at Tanis
442
00:27:56,880 --> 00:27:58,960
shortly before the impact.
443
00:27:58,960 --> 00:28:01,320
GROWLING
444
00:28:06,480 --> 00:28:08,040
And if they were thriving...
445
00:28:08,040 --> 00:28:09,360
SQUAWKING
446
00:28:10,760 --> 00:28:14,440
..they must have been reproducing.
447
00:28:21,080 --> 00:28:24,080
Fossils from dinosaurs
similar to T-rex
448
00:28:24,080 --> 00:28:27,280
show they may have laid
around 20 eggs
449
00:28:27,280 --> 00:28:29,280
in a circular nest.
450
00:28:34,840 --> 00:28:37,280
It's possible that, like crocodiles,
451
00:28:37,280 --> 00:28:40,680
they partly covered their eggs
to keep them warm.
452
00:28:42,120 --> 00:28:43,720
SNEEZES
453
00:28:56,240 --> 00:28:59,360
For one T-rex, a misfortune.
454
00:29:06,360 --> 00:29:09,080
But for all dinosaurs...
455
00:29:09,080 --> 00:29:10,280
ROARS
456
00:29:10,280 --> 00:29:13,320
..a disaster was looming.
457
00:29:26,320 --> 00:29:30,720
Deep in space,
the asteroid was approaching.
458
00:29:35,440 --> 00:29:37,440
Its journey would take it through
the orbit
459
00:29:37,440 --> 00:29:40,240
of our neighbouring planet, Mars.
460
00:29:45,880 --> 00:29:47,720
Had the two collided,
461
00:29:47,720 --> 00:29:50,800
a catastrophe on Earth
would've been avoided.
462
00:29:59,640 --> 00:30:01,560
But it was not to be...
463
00:30:03,120 --> 00:30:05,800
..and Earth's fate was sealed.
464
00:30:19,560 --> 00:30:21,560
As Robert's dig continues,
465
00:30:21,560 --> 00:30:23,640
his vision of what happened at Tanis
466
00:30:23,640 --> 00:30:26,480
is finally starting to come
together.
467
00:30:28,480 --> 00:30:31,320
It seems the sandbank was full
of life.
468
00:30:31,320 --> 00:30:33,840
T-rex, triceratops,
469
00:30:33,840 --> 00:30:35,080
little mammals,
470
00:30:35,080 --> 00:30:39,000
alongside the footprints of
other dinosaurs and pterosaurs,
471
00:30:39,000 --> 00:30:41,040
all in a very small area.
472
00:30:42,840 --> 00:30:44,800
BLOWS
473
00:30:42,840 --> 00:30:44,800
You see the scales?
474
00:30:44,800 --> 00:30:46,840
I do. Oh, my God.
475
00:30:46,840 --> 00:30:49,080
That excites me just looking at it!
476
00:30:50,960 --> 00:30:54,560
Then Robert finds
something truly remarkable.
477
00:30:57,880 --> 00:31:00,600
See the cracks already forming?
Look at that.
478
00:31:00,600 --> 00:31:03,520
So we're going to have to really
monitor that before we glue it.
479
00:31:03,520 --> 00:31:05,880
Cos this is getting vulnerable
now.
480
00:31:05,880 --> 00:31:08,320
An almost complete creature.
481
00:31:11,440 --> 00:31:13,800
To get this block out,
we're freezing it.
482
00:31:20,440 --> 00:31:23,360
Robert is about to attempt
something tricky.
483
00:31:25,200 --> 00:31:27,760
Steady... Let's go.
484
00:31:29,640 --> 00:31:32,640
To get the fossil out
in one piece, they're trying
485
00:31:32,640 --> 00:31:35,120
to freeze it using liquid nitrogen
486
00:31:35,120 --> 00:31:38,280
at almost 200 degrees below zero.
487
00:31:44,080 --> 00:31:45,440
Watch your footing.
488
00:31:46,720 --> 00:31:48,880
Loren, I'm worried
about brittleness here.
489
00:31:48,880 --> 00:31:52,200
Get that hammer. Give this a couple
whacks with the hammer.
490
00:31:53,840 --> 00:31:56,800
OK. Move over five centimetres.
Good.
491
00:32:00,000 --> 00:32:03,600
It's cracked loose. Yep.
OK. It's loose.
492
00:32:03,600 --> 00:32:06,120
So we have to get this out
in one piece.
493
00:32:06,120 --> 00:32:09,160
One, two, three.
494
00:32:10,760 --> 00:32:12,480
Yeehaw!
495
00:32:13,680 --> 00:32:15,640
Total success. Total success.
496
00:32:17,120 --> 00:32:19,800
This is a technique
used in archaeology
497
00:32:19,800 --> 00:32:22,240
for digging up human remains.
498
00:32:22,240 --> 00:32:24,400
We've got enough time
to work with the fossil
499
00:32:24,400 --> 00:32:26,120
and not damage it.
500
00:32:26,120 --> 00:32:28,600
And I couldn't be happier.
501
00:32:31,360 --> 00:32:33,640
And the creature Robert found?
502
00:32:35,120 --> 00:32:36,480
A turtle.
503
00:32:38,560 --> 00:32:42,440
This is the fossil
now it's been cleaned up.
504
00:32:42,440 --> 00:32:45,080
It's lying on its side.
505
00:32:45,080 --> 00:32:47,960
Here's the outline of its shell.
506
00:32:49,280 --> 00:32:53,000
The shape of the shell
and the scalloped edges here
507
00:32:53,000 --> 00:32:55,720
tell us that this was
a baenid turtle.
508
00:32:59,240 --> 00:33:02,520
Robert's baenid turtle
looks very similar
509
00:33:02,520 --> 00:33:04,320
to modern cooter turtles
510
00:33:04,320 --> 00:33:07,720
and lived in the same sort
of freshwater environment.
511
00:33:14,760 --> 00:33:17,920
For a turtle,
Tanis would've been ideal.
512
00:33:21,800 --> 00:33:24,520
Warm, shallow water.
513
00:33:26,760 --> 00:33:28,080
Plenty to eat.
514
00:33:32,880 --> 00:33:35,800
And lots of safe places
in which to warm up
515
00:33:35,800 --> 00:33:37,960
in the Late Cretaceous sunshine.
516
00:33:42,720 --> 00:33:46,320
The turtle fossil Robert found
is almost complete.
517
00:33:46,320 --> 00:33:49,200
This is the underside,
518
00:33:49,200 --> 00:33:54,280
and this brown material up here
is fossilised wood.
519
00:33:54,280 --> 00:33:58,000
It's the end of a stick that passes
right through its body
520
00:33:58,000 --> 00:34:01,200
and comes out just here.
521
00:34:01,200 --> 00:34:03,000
So the evidence points towards
522
00:34:03,000 --> 00:34:05,280
this turtle having been impaled.
523
00:34:08,000 --> 00:34:11,120
A violent end to one of
the many creatures found
524
00:34:11,120 --> 00:34:14,400
in the crumbly rock layer at Tanis.
525
00:34:15,440 --> 00:34:17,080
When I look at the animals
526
00:34:17,080 --> 00:34:19,720
and plants preserved
in the sediments of Tanis
527
00:34:19,720 --> 00:34:21,440
and the footprints beneath it,
528
00:34:21,440 --> 00:34:24,080
I see a picture of
a vibrant ecosystem,
529
00:34:24,080 --> 00:34:28,240
many different dinosaurs,
and a thriving, thriving place.
530
00:34:31,560 --> 00:34:33,480
After ten years of digging,
531
00:34:33,480 --> 00:34:36,600
there is now enough evidence
to piece together
532
00:34:36,600 --> 00:34:38,440
much of the story of Tanis
533
00:34:38,440 --> 00:34:41,080
and the creatures which lived here.
534
00:34:44,600 --> 00:34:48,200
Robert has found so many fossils,
it looks as if,
535
00:34:48,200 --> 00:34:50,600
even at the very end
of the Late Cretaceous,
536
00:34:50,600 --> 00:34:52,680
Tanis was bursting with life.
537
00:34:52,680 --> 00:34:54,600
VARIOUS ANIMAL CALLS
538
00:34:54,600 --> 00:34:58,440
Full of the giant reptiles
that had dominated the planet
539
00:34:58,440 --> 00:35:01,520
for more than 150 million years.
540
00:35:06,400 --> 00:35:07,440
BARKING
541
00:35:07,440 --> 00:35:10,640
It's impossible to know
how much longer
542
00:35:10,640 --> 00:35:12,280
their reign would've continued...
543
00:35:14,320 --> 00:35:15,760
SQUAWKS
544
00:35:15,760 --> 00:35:20,240
..because all this was about to end.
545
00:35:41,480 --> 00:35:43,400
The asteroid hit...
546
00:35:47,080 --> 00:35:51,280
..in what is now the Yucatan
peninsula in Mexico.
547
00:35:54,120 --> 00:35:56,800
It's called the Chicxulub asteroid
548
00:35:56,800 --> 00:35:59,720
after the town nearest
to the centre of its crater.
549
00:36:02,840 --> 00:36:04,520
ROARING
550
00:36:10,920 --> 00:36:12,760
ROARS
551
00:36:17,920 --> 00:36:22,160
Any living thing within 900 miles
of the impact...
552
00:36:24,280 --> 00:36:27,120
..was destroyed by the blast.
553
00:36:32,000 --> 00:36:34,840
But what effect
did the impact have on Tanis,
554
00:36:34,840 --> 00:36:37,360
nearly 2,000 miles away?
555
00:36:47,080 --> 00:36:48,640
To find out,
556
00:36:48,640 --> 00:36:52,720
Robert is looking for clues
that might link Tanis
557
00:36:52,720 --> 00:36:55,920
to the actual day the asteroid hit.
558
00:36:57,040 --> 00:36:58,480
BLOWS
559
00:37:01,920 --> 00:37:03,320
We've got some wood,
560
00:37:03,320 --> 00:37:06,320
and pressed up against this
and all intertangled,
561
00:37:06,320 --> 00:37:08,200
we've got the carcasses of fish.
562
00:37:08,200 --> 00:37:09,520
OK.
563
00:37:10,760 --> 00:37:12,720
That's a beautifully preserved
tail,
564
00:37:12,720 --> 00:37:15,640
so that fish is going to be
absolutely gorgeous.
565
00:37:15,640 --> 00:37:18,200
So part of the detail work
that we're doing right now
566
00:37:18,200 --> 00:37:19,840
is going in and checking out
567
00:37:19,840 --> 00:37:23,600
all the individual elements
in this mass death layer.
568
00:37:23,600 --> 00:37:26,840
Some of the evidence
he's found so far
569
00:37:26,840 --> 00:37:30,400
has been hidden inside
the fish themselves.
570
00:37:33,480 --> 00:37:36,640
In more ways than one, it literally
is an operation of a Cretaceous
571
00:37:36,640 --> 00:37:39,640
fish, so we're performing surgery
on this thing.
572
00:37:39,640 --> 00:37:42,680
Robert needs to open this
fish's skull.
573
00:37:44,400 --> 00:37:47,720
And very carefully,
we want to separate this
574
00:37:47,720 --> 00:37:49,200
from the rest of the fish.
575
00:37:50,440 --> 00:37:51,760
OK.
576
00:37:55,320 --> 00:37:57,640
Here we go.
577
00:37:57,640 --> 00:37:59,880
Opening up the fish.
578
00:37:59,880 --> 00:38:02,080
Got a nice ant
that made a home in there.
579
00:38:03,200 --> 00:38:04,880
And beautiful, look at that.
580
00:38:04,880 --> 00:38:07,920
OK, here we have
the gill bars of the fish.
581
00:38:07,920 --> 00:38:10,560
Those are the bars that hold
the filaments of the gills.
582
00:38:11,760 --> 00:38:13,480
And between the gill bars,
583
00:38:13,480 --> 00:38:15,560
all of these clusters
of round objects,
584
00:38:15,560 --> 00:38:17,360
those are the ejecta spherules.
585
00:38:18,400 --> 00:38:22,840
Ejecta spherules are tiny balls
that were once molten rock.
586
00:38:22,840 --> 00:38:25,440
They could be evidence
of what Robert suspects -
587
00:38:25,440 --> 00:38:27,040
that creatures here died
588
00:38:27,040 --> 00:38:29,760
on the day
of the asteroid strike.
589
00:38:30,960 --> 00:38:33,880
Those ejecta spherules
last saw the light of day
590
00:38:33,880 --> 00:38:36,880
when they were flying through
the air 66 billion years ago.
591
00:38:47,400 --> 00:38:51,000
After a large asteroid impact,
592
00:38:51,000 --> 00:38:53,760
a mix of vaporised and molten rock
593
00:38:53,760 --> 00:38:55,880
is propelled into space.
594
00:38:58,840 --> 00:39:00,400
There, it cools,
595
00:39:00,400 --> 00:39:03,600
solidifying
into tiny glass droplets.
596
00:39:05,160 --> 00:39:08,280
Some carry on deeper into space.
597
00:39:10,440 --> 00:39:13,760
But most are pulled back
to Earth by gravity.
598
00:39:21,280 --> 00:39:24,120
After a major asteroid hit,
599
00:39:24,120 --> 00:39:28,840
trillions of ejecta spherules
would fall from the sky.
600
00:39:28,840 --> 00:39:31,040
Then, over millions of years,
601
00:39:31,040 --> 00:39:34,040
pressure and chemical reactions
in the ground
602
00:39:34,040 --> 00:39:37,200
would turn most of them to clay.
603
00:39:37,200 --> 00:39:39,760
They'd look something like this.
604
00:39:40,840 --> 00:39:44,960
So finding spherules
in the gills of a fish,
605
00:39:44,960 --> 00:39:47,280
as Robert has done at Tanis,
606
00:39:47,280 --> 00:39:49,680
suggests the fish sucked them in
607
00:39:49,680 --> 00:39:52,480
while the spherules
were still falling.
608
00:39:52,480 --> 00:39:54,280
So these creatures could have died
609
00:39:54,280 --> 00:39:57,160
at the time of an asteroid impact.
610
00:40:02,560 --> 00:40:05,960
Once Robert begins to look
for ejecta spherules,
611
00:40:05,960 --> 00:40:07,640
he finds more and more,
612
00:40:07,640 --> 00:40:12,040
and realises the thick,
crumbly layer of rock at Tanis
613
00:40:12,040 --> 00:40:13,440
is full of them.
614
00:40:16,760 --> 00:40:19,000
I mean, this stuff is go...
Oh, my God, look at that one.
615
00:40:19,000 --> 00:40:20,960
These things are just gorgeous.
616
00:40:22,440 --> 00:40:23,840
Ejecta spherules like this
617
00:40:23,840 --> 00:40:26,440
give us a fingerprint
of where they came from.
618
00:40:28,080 --> 00:40:30,120
If these spherules were connected
619
00:40:30,120 --> 00:40:31,880
to the Chicxulub impact,
620
00:40:31,880 --> 00:40:35,000
then the whole crumbly layer
could be full of evidence
621
00:40:35,000 --> 00:40:38,680
of what happened on the day
the asteroid hit.
622
00:40:38,680 --> 00:40:39,960
That's a good one.
623
00:40:39,960 --> 00:40:42,360
Oh, is that a droplet right there?
624
00:40:42,360 --> 00:40:44,320
To see if that's the case,
625
00:40:44,320 --> 00:40:47,960
Robert needs to find a spherule
that hasn't turned to clay.
626
00:40:47,960 --> 00:40:51,760
Oh, my God,
that's a beautiful droplet.
627
00:40:51,760 --> 00:40:53,680
OK.
628
00:40:53,680 --> 00:40:56,800
The small pieces of orange material
629
00:40:56,800 --> 00:40:58,640
that Robert and Loren are digging up
630
00:40:58,640 --> 00:41:00,800
may be able to help.
631
00:41:00,800 --> 00:41:03,840
They're amber.
632
00:41:03,840 --> 00:41:06,320
If there was anything flying
through the air at that time,
633
00:41:06,320 --> 00:41:08,160
this is where it's going to get
caught.
634
00:41:10,480 --> 00:41:13,800
The amber they're collecting
was once sticky resin
635
00:41:13,800 --> 00:41:16,920
oozing out of
a Late Cretaceous tree trunk.
636
00:41:18,720 --> 00:41:21,120
It's a way for the tree
to protect itself,
637
00:41:21,120 --> 00:41:23,920
like a scab forming on a cut.
638
00:41:32,120 --> 00:41:34,960
Anything covered by the resin
would be frozen
639
00:41:34,960 --> 00:41:37,000
in an amber time capsule.
640
00:41:43,480 --> 00:41:45,840
If they find a spherule
preserved in amber,
641
00:41:45,840 --> 00:41:48,400
it could be analysed
642
00:41:48,400 --> 00:41:51,560
to see if it comes from
the Chicxulub asteroid impact.
643
00:41:54,640 --> 00:41:56,080
So during this batch,
644
00:41:56,080 --> 00:41:59,640
we were incredibly lucky
that we came across
645
00:41:59,640 --> 00:42:02,080
two completely unaltered spherules.
646
00:42:03,560 --> 00:42:06,960
This spherule could be
something amazing.
647
00:42:06,960 --> 00:42:11,600
Evidence preserved well enough
to analyse for chemical clues.
648
00:42:14,480 --> 00:42:15,880
If so,
649
00:42:15,880 --> 00:42:20,440
it could link Tanis directly
with the Chicxulub impact
650
00:42:20,440 --> 00:42:22,920
and the last day of the dinosaurs.
651
00:42:30,520 --> 00:42:33,160
To investigate, Robert is joined
652
00:42:33,160 --> 00:42:35,240
at the Diamond Light Source
653
00:42:35,240 --> 00:42:38,120
by Professor of Natural History
Phil Manning,
654
00:42:38,120 --> 00:42:40,440
of the University of Manchester.
655
00:42:40,440 --> 00:42:42,920
They've already run initial tests
656
00:42:42,920 --> 00:42:44,920
on the spherules in America.
657
00:42:44,920 --> 00:42:46,800
What have you found out so far?
658
00:42:46,800 --> 00:42:50,560
These little glass spherules,
these globs
659
00:42:50,560 --> 00:42:52,520
of molten material
from the impact site
660
00:42:52,520 --> 00:42:55,960
have a chemical signal that ties it
with where they came from.
661
00:42:55,960 --> 00:42:57,480
Cos when an asteroid hits,
662
00:42:57,480 --> 00:42:59,680
it melts the ground that it hits,
663
00:42:59,680 --> 00:43:01,920
but also that glass has
664
00:43:01,920 --> 00:43:04,520
a little bit of contamination
from the asteroid itself.
665
00:43:04,520 --> 00:43:07,920
And that gives you a unique
geochemical fingerprint.
666
00:43:07,920 --> 00:43:09,440
We can see once we've scanned it,
667
00:43:09,440 --> 00:43:12,280
and looking at spherules from
other sites in North Dakota,
668
00:43:12,280 --> 00:43:13,960
we can get a baseline
669
00:43:13,960 --> 00:43:18,200
for what the ejecta should look
like when it's related to
670
00:43:18,200 --> 00:43:19,880
the Chicxulub crater.
671
00:43:19,880 --> 00:43:21,440
And you can see each element here
672
00:43:21,440 --> 00:43:23,480
and the ratios of those elements.
673
00:43:23,480 --> 00:43:26,720
And when we look at Tanis,
it's a match.
674
00:43:26,720 --> 00:43:29,480
I mean, it perfectly overlays.
675
00:43:29,480 --> 00:43:32,480
So I think
this is powerful evidence
676
00:43:32,480 --> 00:43:36,080
supporting that Tanis
and Chicxulub are linked.
677
00:43:36,080 --> 00:43:38,120
And what do these findings mean
678
00:43:38,120 --> 00:43:41,040
for the rest of the fossils
that you're finding in Tanis?
679
00:43:41,040 --> 00:43:44,080
This data is key for the
entire site,
680
00:43:44,080 --> 00:43:46,360
because once you have that link
681
00:43:46,360 --> 00:43:49,120
and you know
what impact affected Tanis,
682
00:43:49,120 --> 00:43:52,760
then you essentially know
that every object in that site,
683
00:43:52,760 --> 00:43:55,640
all the animals and the plants
and everything buried
684
00:43:55,640 --> 00:43:57,000
in those sediments,
685
00:43:57,000 --> 00:43:59,640
are linked to the last day
of the Cretaceous.
686
00:44:01,560 --> 00:44:04,480
And the synchrotron here in the UK
687
00:44:04,480 --> 00:44:07,040
reveals something even more
remarkable.
688
00:44:09,440 --> 00:44:14,000
So this is showing
a beautiful synchrotron scan
689
00:44:14,000 --> 00:44:16,400
of the half of one spherule.
690
00:44:16,400 --> 00:44:19,240
The glass is
a good geochemical fingerprint,
691
00:44:19,240 --> 00:44:22,920
and we've got calcium, some iron,
692
00:44:22,920 --> 00:44:24,960
we've got strontium,
693
00:44:24,960 --> 00:44:26,760
but when we look at the
entire thing,
694
00:44:26,760 --> 00:44:29,720
we see something quite unexpected.
695
00:44:29,720 --> 00:44:31,880
That's your entire spherule.
696
00:44:31,880 --> 00:44:33,280
What's this?
697
00:44:33,280 --> 00:44:36,280
In this, we've got
a little bit of a nugget.
698
00:44:36,280 --> 00:44:38,520
There was a little particle
right there.
699
00:44:38,520 --> 00:44:39,760
So we scan it.
700
00:44:39,760 --> 00:44:42,240
And that's a lot of iron
in there.
701
00:44:42,240 --> 00:44:45,080
Over here, we've got chromium,
a big peak in chromium.
702
00:44:45,080 --> 00:44:48,160
Over here, we've got
a big peak in nickel.
703
00:44:48,160 --> 00:44:50,960
And the abundances
of iron, nickel and chromium,
704
00:44:50,960 --> 00:44:52,400
all together,
705
00:44:52,400 --> 00:44:55,120
that matches what you expect
to see in a meteoric body.
706
00:44:55,120 --> 00:44:58,120
That does not match what you
would normally have down here.
707
00:44:58,120 --> 00:45:01,720
So this is
extraterrestrial material?
708
00:45:01,720 --> 00:45:03,960
If you were to sort of grind up
709
00:45:03,960 --> 00:45:09,320
and stuff into a spherule
a piece of meteorite,
710
00:45:09,320 --> 00:45:11,200
that's what it's going to look
like.
711
00:45:11,200 --> 00:45:14,560
This could be a piece of
the Chicxulub asteroid.
712
00:45:14,560 --> 00:45:16,760
A piece of the bullet
that killed the dinosaurs.
713
00:45:16,760 --> 00:45:18,160
No!
714
00:45:24,720 --> 00:45:26,320
Robert could have found
715
00:45:26,320 --> 00:45:29,680
a fragment of the asteroid itself
in Tanis,
716
00:45:29,680 --> 00:45:35,440
physical evidence linking this site
to the Chicxulub impact.
717
00:45:35,440 --> 00:45:38,680
But Tanis is almost 2,000 miles away
718
00:45:38,680 --> 00:45:40,600
from where the asteroid hit.
719
00:45:40,600 --> 00:45:44,400
So exactly how did it cause
the creatures' deaths?
720
00:45:48,080 --> 00:45:50,200
To answer that question,
721
00:45:50,200 --> 00:45:53,880
Robert is searching
in the mass death layer.
722
00:45:56,520 --> 00:46:00,280
Right here, we've got
this intertangled mass of fish.
723
00:46:00,280 --> 00:46:02,800
There's one fish here,
another sturgeon goes this way,
724
00:46:02,800 --> 00:46:04,800
underneath the body of a paddlefish.
725
00:46:04,800 --> 00:46:06,680
There's another sturgeon
that goes this way,
726
00:46:06,680 --> 00:46:10,240
underneath this log, and continues
out the other side.
727
00:46:10,240 --> 00:46:12,400
And his head hit that log
728
00:46:12,400 --> 00:46:15,760
and has deflected downward
at a 90-degree angle.
729
00:46:17,760 --> 00:46:22,840
Robert uncovered a tangled mass of
fossilised creatures and logs
730
00:46:22,840 --> 00:46:25,040
surrounded by spherules
731
00:46:25,040 --> 00:46:29,480
and crushed together
in what's known as a logjam.
732
00:46:29,480 --> 00:46:32,280
He has a theory that
the creatures were swept
733
00:46:32,280 --> 00:46:35,760
to their death in some kind
of turbulent surge of water
734
00:46:35,760 --> 00:46:38,120
and quickly entombed in sediment,
735
00:46:38,120 --> 00:46:40,960
which is why
they're so well preserved.
736
00:46:40,960 --> 00:46:43,720
But what could have caused the wave?
737
00:46:47,560 --> 00:46:50,200
One theory is a tsunami.
738
00:46:54,360 --> 00:46:56,880
The asteroid hit at sea.
739
00:46:56,880 --> 00:46:58,440
Recent studies show
740
00:46:58,440 --> 00:47:02,480
it may have caused a wave
almost a mile high.
741
00:47:15,400 --> 00:47:18,280
The height of the wave
would've gradually reduced
742
00:47:18,280 --> 00:47:20,520
as it spread across the oceans.
743
00:47:22,000 --> 00:47:23,480
In the Late Cretaceous,
744
00:47:23,480 --> 00:47:26,600
North America was divided
by a narrow sea
745
00:47:26,600 --> 00:47:29,840
that's been called
the Western Interior Seaway.
746
00:47:29,840 --> 00:47:32,640
The tsunami could have
travelled up this,
747
00:47:32,640 --> 00:47:34,240
towards Tanis.
748
00:47:37,680 --> 00:47:40,440
But there's a big question
about the tsunami idea.
749
00:47:42,040 --> 00:47:44,000
The timing.
750
00:47:44,000 --> 00:47:46,920
Oh, which fish is that?
751
00:47:46,920 --> 00:47:50,040
That's a new...
It's a new contact. New one. Yeah.
752
00:47:50,040 --> 00:47:52,920
If a tsunami killed the fish,
753
00:47:52,920 --> 00:47:54,960
it would have to have hit
754
00:47:54,960 --> 00:47:56,760
while ejecta spherules
were falling...
755
00:47:58,080 --> 00:48:02,160
..because spherules were found
in the fish's gills.
756
00:48:03,880 --> 00:48:09,200
So how long after impact did
the spherules arrive at Tanis?
757
00:48:09,200 --> 00:48:11,680
Pretend this ball of foil
is a piece of ejecta
758
00:48:11,680 --> 00:48:14,840
coming out of the crater. It would
then go on an arc path,
759
00:48:14,840 --> 00:48:16,840
ballistic trajectory,
out of the crater
760
00:48:16,840 --> 00:48:19,400
and to wherever it lands -
in this case, Tanis.
761
00:48:21,480 --> 00:48:24,000
If we know the distance
between myself
762
00:48:24,000 --> 00:48:27,360
and the landing site, and if we know
the size of that ball,
763
00:48:27,360 --> 00:48:30,560
we can accurately calculate how long
it would take to get there.
764
00:48:34,560 --> 00:48:36,480
The result is surprising.
765
00:48:36,480 --> 00:48:38,960
Robert and his team calculated
766
00:48:38,960 --> 00:48:42,320
that these ejecta spherules
landed at Tanis
767
00:48:42,320 --> 00:48:46,680
between 13 minutes
and two hours after the impact.
768
00:48:49,280 --> 00:48:51,320
If a wave killed the fish,
769
00:48:51,320 --> 00:48:54,680
it must also have reached Tanis
within two hours.
770
00:48:58,760 --> 00:49:01,040
Data from recent tsunamis show
771
00:49:01,040 --> 00:49:04,400
even a powerful one would take much
longer than that
772
00:49:04,400 --> 00:49:08,200
to travel almost 2,000 miles
from the impact site
773
00:49:08,200 --> 00:49:09,640
to Tanis.
774
00:49:10,640 --> 00:49:13,280
So if it wasn't a tsunami,
775
00:49:13,280 --> 00:49:16,040
what could have caused
a surge of water at Tanis?
776
00:49:25,320 --> 00:49:29,320
Professor Stein Bondevik
is an expert in tsunamis.
777
00:49:34,800 --> 00:49:37,720
The fjords in Norway
are very special.
778
00:49:39,120 --> 00:49:43,120
We have tall mountains
surrounding bodies of water.
779
00:49:43,120 --> 00:49:46,400
So the water is usually very calm.
780
00:49:46,400 --> 00:49:51,120
In 2011, something very strange
happened.
781
00:49:51,120 --> 00:49:55,480
The water in the fjord
began to move violently.
782
00:49:55,480 --> 00:50:00,080
The height of the water increased
by one and a half metre,
783
00:50:00,080 --> 00:50:04,080
like a maelstrom
with the turbulent water.
784
00:50:04,080 --> 00:50:06,800
Someone said
that the fjord was boiling.
785
00:50:06,800 --> 00:50:08,400
THUNDER RUMBLES
786
00:50:08,400 --> 00:50:10,240
News started to roll in -
787
00:50:10,240 --> 00:50:14,520
there'd been an earthquake
5,000 miles away in Japan.
788
00:50:17,440 --> 00:50:20,240
A journalist from
the local newspaper called me,
789
00:50:20,240 --> 00:50:23,160
and he said that
people were observing waves
790
00:50:23,160 --> 00:50:24,560
here, in the fjords.
791
00:50:26,680 --> 00:50:29,160
I got a video clip of the waves.
792
00:50:29,160 --> 00:50:32,600
I saw immediately that they looked
like a tsunami wave.
793
00:50:32,600 --> 00:50:34,440
So later in the afternoon,
794
00:50:34,440 --> 00:50:37,600
you can see that the fjord is
perfectly calm.
795
00:50:39,240 --> 00:50:40,480
But at the beach here,
796
00:50:40,480 --> 00:50:43,600
you could see that the water
is sloshing back and forth,
797
00:50:43,600 --> 00:50:46,560
and no-one had ever seen
anything like it.
798
00:50:47,920 --> 00:50:51,120
And some people
got very upset and afraid.
799
00:50:54,320 --> 00:50:59,560
A magnitude nine earthquake had
devastated the northeast of Japan,
800
00:50:59,560 --> 00:51:01,560
around Fukushima.
801
00:51:04,440 --> 00:51:08,280
But how did that affect a fjord
so far away?
802
00:51:10,920 --> 00:51:13,840
So no-one in Norway
could feel the earthquake,
803
00:51:13,840 --> 00:51:17,400
but I could see that
the times matched
804
00:51:17,400 --> 00:51:20,200
the arrival of the waves here,
in the fjord.
805
00:51:23,920 --> 00:51:27,200
Eventually,
Stein and his team realised
806
00:51:27,200 --> 00:51:31,960
that this might have something
to do with seismic waves -
807
00:51:31,960 --> 00:51:35,120
shock waves that pass quickly
through the Earth
808
00:51:35,120 --> 00:51:36,680
during an earthquake.
809
00:51:38,080 --> 00:51:41,560
So it took only 12 minutes
before the first signal
810
00:51:41,560 --> 00:51:44,240
of the earthquake in Japan
reached all the way here,
811
00:51:44,240 --> 00:51:45,600
to western Norway.
812
00:51:48,120 --> 00:51:49,920
So it was the seismic waves
813
00:51:49,920 --> 00:51:52,720
that caused the normally calm
water in the fjord
814
00:51:52,720 --> 00:51:55,680
to slosh turbulently
back and forth.
815
00:51:57,480 --> 00:52:02,440
Just thinking of that,
scientifically, it's fantastic.
816
00:52:08,560 --> 00:52:12,360
Could something similar
have happened in Tanis?
817
00:52:12,360 --> 00:52:15,680
A large weather front's
coming through the northwest...
818
00:52:17,120 --> 00:52:19,000
Trying to find out
819
00:52:19,000 --> 00:52:22,240
is geophysicist professor
Mark Richards,
820
00:52:22,240 --> 00:52:25,800
who's been studying the site at
Tanis for several years.
821
00:52:26,920 --> 00:52:29,280
He's working with Robert
to discover
822
00:52:29,280 --> 00:52:32,120
what could have caused
a surge of water here.
823
00:52:39,240 --> 00:52:42,520
A tsunami can't get here
in less than minimum 12 hours.
824
00:52:44,400 --> 00:52:48,240
But seismic waves travelling
from the Yucatan impact site
825
00:52:48,240 --> 00:52:51,120
to North Dakota
can arrive here fairly quickly.
826
00:52:53,400 --> 00:52:57,320
In the Late Cretaceous,
the Western Interior Seaway
827
00:52:57,320 --> 00:53:01,440
that divided North America could
have been connected to Tanis
828
00:53:01,440 --> 00:53:03,360
through a system of rivers.
829
00:53:08,600 --> 00:53:11,080
If you have
a very large body of water,
830
00:53:11,080 --> 00:53:14,080
like the Western Interior Seaway,
831
00:53:14,080 --> 00:53:16,360
and you can shake it back and forth,
832
00:53:16,360 --> 00:53:19,600
you can generate
a large water wave
833
00:53:19,600 --> 00:53:22,200
coming up this river at Tanis.
834
00:53:26,680 --> 00:53:30,400
So seismic waves from the impact
could have caused
835
00:53:30,400 --> 00:53:33,320
surges of water
in the Tanis river system.
836
00:53:34,400 --> 00:53:37,560
The seismic waves
get here quickly enough,
837
00:53:37,560 --> 00:53:39,920
coming up the Tanis river,
838
00:53:39,920 --> 00:53:42,320
inundating this area,
arriving at the same time
839
00:53:42,320 --> 00:53:45,000
these spherules are
still falling out of the air.
840
00:53:47,840 --> 00:53:49,440
The mystery of the wave
841
00:53:49,440 --> 00:53:53,760
and the thick layer of crumbly rock
has been solved.
842
00:53:53,760 --> 00:53:56,280
Seismic waves travelling
through the Earth
843
00:53:56,280 --> 00:54:00,120
could have caused powerful surges of
water at Tanis...
844
00:54:02,760 --> 00:54:05,240
..possibly carrying mud
and marine creatures,
845
00:54:05,240 --> 00:54:09,320
like ammonites, from the Western
Interior Seaway...
846
00:54:12,160 --> 00:54:16,680
..dumping them on the Tanis sandbank
and burying everything
847
00:54:16,680 --> 00:54:19,600
at the same time as spherules fell.
848
00:54:28,000 --> 00:54:29,240
Over millions of years,
849
00:54:29,240 --> 00:54:33,440
the mud would turn into
the layer of crumbly rock.
850
00:54:35,200 --> 00:54:37,280
And that's the beauty of Tanis.
851
00:54:37,280 --> 00:54:40,400
What you're seeing is a deposit
852
00:54:40,400 --> 00:54:44,760
that is literally recording
the last, say,
853
00:54:44,760 --> 00:54:48,600
45 minutes to an hour and a half
of the Cretaceous.
854
00:54:58,760 --> 00:55:01,960
If the extinction
of the dinosaurs was a crime,
855
00:55:01,960 --> 00:55:06,240
the detective solving it
would have plenty of evidence.
856
00:55:06,240 --> 00:55:08,160
They would see
that the asteroid was
857
00:55:08,160 --> 00:55:10,760
in the right place
at the right time.
858
00:55:10,760 --> 00:55:13,360
They would see
that no dinosaurs survived
859
00:55:13,360 --> 00:55:14,800
after the hit.
860
00:55:15,800 --> 00:55:18,120
They would have a piece
of the murder weapon -
861
00:55:18,120 --> 00:55:20,200
a fragment of the asteroid.
862
00:55:20,200 --> 00:55:24,160
But they would be missing
one very important thing -
863
00:55:24,160 --> 00:55:25,720
a body.
864
00:55:30,280 --> 00:55:34,000
No-one has ever found
the fossil of a dinosaur
865
00:55:34,000 --> 00:55:38,360
that was killed by the effects
of the asteroid impact.
866
00:55:38,360 --> 00:55:41,960
But Robert did find
part of a triceratops
867
00:55:41,960 --> 00:55:44,280
in the crumbly layer at Tanis.
868
00:55:44,280 --> 00:55:46,480
So could that be the remains
869
00:55:46,480 --> 00:55:49,360
of a dinosaur
that died on that day?
870
00:55:49,360 --> 00:55:50,880
I'm still dubious about the horn.
871
00:55:50,880 --> 00:55:52,880
I kind of want to keep
the horn in the jacket.
872
00:55:52,880 --> 00:55:54,120
I think if you took it off,
873
00:55:54,120 --> 00:55:55,760
at least take this section off,
874
00:55:55,760 --> 00:55:57,400
to see what's going on under here.
875
00:55:57,400 --> 00:55:58,560
Yeah?
876
00:55:58,560 --> 00:56:03,400
To find out, the team needs to
establish cause of death,
877
00:56:03,400 --> 00:56:06,760
which can be difficult when you only
have a piece of skin
878
00:56:06,760 --> 00:56:08,880
and a horn to go on.
879
00:56:11,000 --> 00:56:15,120
This is the horn
after they've cleaned it up.
880
00:56:15,120 --> 00:56:19,600
The team is particularly
interested in these lines here.
881
00:56:19,600 --> 00:56:22,200
And they found that the fractures go
882
00:56:22,200 --> 00:56:24,800
right through the horn.
883
00:56:24,800 --> 00:56:28,080
So rather than dying
as a result of the impact,
884
00:56:28,080 --> 00:56:31,440
they wondered whether
it had been killed in a fight.
885
00:56:37,160 --> 00:56:39,560
But when they looked at
the fractures in more detail,
886
00:56:39,560 --> 00:56:42,440
they found signs
of new bone growth here.
887
00:56:43,480 --> 00:56:46,880
An indication that
the bone had started to heal.
888
00:56:46,880 --> 00:56:49,440
So it looked as though
the triceratops survived
889
00:56:49,440 --> 00:56:51,880
the event that broke its horn.
890
00:56:56,520 --> 00:56:59,280
Could this triceratops
have survived
891
00:56:59,280 --> 00:57:02,000
until the day of the impact?
892
00:57:02,000 --> 00:57:05,640
The team found evidence,
including sagging in the skin,
893
00:57:05,640 --> 00:57:09,400
which suggested that
there was decay underneath.
894
00:57:09,400 --> 00:57:11,800
That means its body had started
to rot
895
00:57:11,800 --> 00:57:15,720
before it was entombed
and preserved by the surge.
896
00:57:15,720 --> 00:57:20,760
So it seems that this dinosaur
didn't die as a result
897
00:57:20,760 --> 00:57:22,720
of the asteroid impact.
898
00:57:24,400 --> 00:57:27,520
Perhaps, in the months
before the impact,
899
00:57:27,520 --> 00:57:29,600
the broken horn put the triceratops
900
00:57:29,600 --> 00:57:32,040
at a disadvantage over its rivals.
901
00:57:33,880 --> 00:57:35,520
GRUNTS
902
00:57:47,760 --> 00:57:50,480
And that might have led
to starvation.
903
00:58:01,920 --> 00:58:04,360
THUNDER CRACKS
904
00:58:08,840 --> 00:58:10,400
WIND WHOOSHES
905
00:58:12,600 --> 00:58:15,880
Robert has still not found
direct evidence
906
00:58:15,880 --> 00:58:18,840
of a dinosaur that was killed
by the asteroid.
907
00:58:20,040 --> 00:58:22,120
We've got all these bones
in the ground right now.
908
00:58:22,120 --> 00:58:24,920
But the one thing
that we would just dream
909
00:58:24,920 --> 00:58:26,880
of finding is that one dinosaur
910
00:58:26,880 --> 00:58:29,520
that died on the day of the impact.
911
00:58:33,400 --> 00:58:36,560
And the weather
isn't helping his search.
912
00:58:42,920 --> 00:58:44,840
GROANS
913
00:58:54,440 --> 00:58:56,640
That therapod print is toasted.
914
00:58:56,640 --> 00:58:58,800
Yeah, it was in a low corner.
915
00:58:58,800 --> 00:59:01,840
Look, it's full mud.
It's full of mud and water.
916
00:59:01,840 --> 00:59:04,000
The problem is it's wet, look.
917
00:59:04,000 --> 00:59:06,720
See... If we're not careful,
we're going to lose the print.
918
00:59:08,040 --> 00:59:10,160
And that's the biggest
theropod print we've got.
919
00:59:11,200 --> 00:59:13,800
I see some areas that could use
glue right now, too.
920
00:59:16,320 --> 00:59:19,640
The team is racing
to excavate the footprints,
921
00:59:19,640 --> 00:59:22,080
along with dozens of fish fossils
922
00:59:22,080 --> 00:59:26,800
tangled together in a logjam,
before storms wash them away.
923
00:59:26,800 --> 00:59:28,160
THUNDER RUMBLES
924
00:59:28,160 --> 00:59:29,760
We're up against the clock here.
925
00:59:29,760 --> 00:59:31,600
This stuff that could be
exposed right now
926
00:59:31,600 --> 00:59:33,440
is going to get ruined by the rain.
927
00:59:36,000 --> 00:59:38,600
But then,
Robert comes across something
928
00:59:38,600 --> 00:59:40,280
that looks very unusual.
929
00:59:40,280 --> 00:59:42,040
That's going there.
930
00:59:43,640 --> 00:59:45,320
What is going on right there?
931
00:59:45,320 --> 00:59:47,680
Are we sure
this isn't crocodilian?
932
00:59:47,680 --> 00:59:49,680
That's not crocodilian. No.
933
00:59:49,680 --> 00:59:52,280
Right, let me try
this piece right here.
934
00:59:52,280 --> 00:59:54,920
I'll go in from the top
and then twist up,
935
00:59:54,920 --> 00:59:56,520
and it separates right on that line.
936
00:59:56,520 --> 00:59:59,040
Oh, that's skin right there.
937
00:59:59,040 --> 01:00:01,520
That's actually scaly skin.
Oh, my God.
938
01:00:01,520 --> 01:00:03,360
No, no, no, no, no.
Look, look, look.
939
01:00:03,360 --> 01:00:05,320
Look at that pattern
right there.
940
01:00:05,320 --> 01:00:08,080
Have you ever seen elongated
scales like that before, Dave?
941
01:00:08,080 --> 01:00:10,320
That's insane.
Scuttelates - in birds.
942
01:00:10,320 --> 01:00:12,080
Just careful.
943
01:00:12,080 --> 01:00:14,440
Oh, my God.
It's changing again.
944
01:00:14,440 --> 01:00:15,960
It's changing again.
Oh, my God.
945
01:00:17,240 --> 01:00:20,760
We're seeing it for the first time
in 66 million years.
946
01:00:20,760 --> 01:00:22,720
I think we've got ourselves
a dinosaur.
947
01:00:27,320 --> 01:00:29,000
A dinosaur fossil!
948
01:00:29,000 --> 01:00:32,120
And, unlike the triceratops,
949
01:00:32,120 --> 01:00:36,360
this is located in the logjam,
the mass death layer,
950
01:00:36,360 --> 01:00:40,680
surrounded by the fish
with spherules in their gills.
951
01:00:43,560 --> 01:00:46,440
This is the most incredible thing
that we could possibly imagine here.
952
01:00:46,440 --> 01:00:48,080
The best-case scenario.
953
01:00:48,080 --> 01:00:51,160
We're excavating
this mass death layer of fish
954
01:00:51,160 --> 01:00:54,040
from the surge
sent up by the impact,
955
01:00:54,040 --> 01:00:56,120
and we've got dinosaur remains.
956
01:00:56,120 --> 01:00:59,400
The one thing that we would always
want to find at this site,
957
01:00:59,400 --> 01:01:01,720
and here we've got it.
958
01:01:01,720 --> 01:01:05,440
This is unreal. I-I-I cannot
process this in my brain.
959
01:01:05,440 --> 01:01:08,080
No, I am absolutely blown away
by this.
960
01:01:08,080 --> 01:01:10,520
Just my heart is literally
pumping out of my chest
961
01:01:10,520 --> 01:01:11,920
wondering what is behind there,
962
01:01:11,920 --> 01:01:14,120
just a couple of centimetres
back in the outcrop.
963
01:01:14,120 --> 01:01:15,760
What is waiting for us back there?
964
01:01:17,480 --> 01:01:19,320
Get it out...
965
01:01:19,320 --> 01:01:20,920
This is...
966
01:01:20,920 --> 01:01:22,240
The team keeps digging.
967
01:01:22,240 --> 01:01:24,200
The scales get big again
over on this side.
968
01:01:24,200 --> 01:01:25,760
So this could be a ribcage,
969
01:01:25,760 --> 01:01:27,920
it could be laying against ribs
that are curved.
970
01:01:27,920 --> 01:01:29,480
There's something here.
971
01:01:29,480 --> 01:01:30,960
That's hard. A bit more bone.
972
01:01:30,960 --> 01:01:32,920
That's bone right next
to the skin.
973
01:01:32,920 --> 01:01:34,960
Yeah, that's an articular
surface right there,
974
01:01:34,960 --> 01:01:37,400
so this is either a hip
or a shoulder element.
975
01:01:41,400 --> 01:01:44,560
After hours
of painstaking work...
976
01:01:47,760 --> 01:01:50,160
And we can go
from the thigh of the animal.
977
01:01:50,160 --> 01:01:51,800
There's the knee.
978
01:01:51,800 --> 01:01:54,520
And then you've got
the little calf muscles
979
01:01:54,520 --> 01:01:56,400
of the dinosaur,
they're bulging out,
980
01:01:56,400 --> 01:01:59,360
and you go down
to the anklebones,
981
01:01:59,360 --> 01:02:02,160
and these are the toes
of the feet.
982
01:02:02,160 --> 01:02:04,200
We have got nails
at the tips of the toes.
983
01:02:04,200 --> 01:02:06,040
It's a beautifully preserved leg,
984
01:02:06,040 --> 01:02:07,880
all articulated, covered with skin.
985
01:02:09,000 --> 01:02:12,840
The complete leg of a dinosaur.
986
01:02:12,840 --> 01:02:14,880
In my wildest dreams,
987
01:02:14,880 --> 01:02:17,120
I never expected to find
a dinosaur leg in this deposit.
988
01:02:17,120 --> 01:02:20,480
Yeah. I mean, and then
it's got skin and tissue.
989
01:02:20,480 --> 01:02:22,960
It does look
just like a drumstick.
990
01:02:22,960 --> 01:02:24,840
It looks like
a Thanksgiving turkey,
991
01:02:24,840 --> 01:02:26,600
just laid out in the ground.
992
01:02:26,600 --> 01:02:30,480
And this weird scale pattern
on the thigh of the animal,
993
01:02:30,480 --> 01:02:33,240
which we've never seen
in a dinosaur before.
994
01:02:33,240 --> 01:02:36,000
Well, thescelosaurs don't have
any form of defence,
995
01:02:36,000 --> 01:02:38,240
so they have to have camouflage
or something.
996
01:02:38,240 --> 01:02:39,680
That's a good point.
997
01:02:39,680 --> 01:02:43,240
So this could have been some
sort of a camouflage marking. Yeah.
998
01:02:43,240 --> 01:02:47,000
Robert thinks he has found
the body in question -
999
01:02:47,000 --> 01:02:51,240
a dinosaur that might itself
have witnessed
1000
01:02:51,240 --> 01:02:53,080
the cataclysmic impact.
1001
01:02:56,280 --> 01:02:58,560
Dinosaur fossils are not known
1002
01:02:58,560 --> 01:03:01,440
from the last years
of the Cretaceous.
1003
01:03:01,440 --> 01:03:04,040
And it was unclear whether
they were already extinct
1004
01:03:04,040 --> 01:03:05,920
or in decline
or what was going on.
1005
01:03:05,920 --> 01:03:07,760
So they were just sort of absent.
1006
01:03:11,320 --> 01:03:12,760
And this answers that question.
1007
01:03:12,760 --> 01:03:15,360
Were dinosaurs still there then?
1008
01:03:15,360 --> 01:03:19,480
Well, yes - this one likely
died in that surge.
1009
01:03:23,320 --> 01:03:27,920
For such big claims,
Robert needs verification.
1010
01:03:30,240 --> 01:03:32,520
He's brought the dinosaur leg
to London
1011
01:03:32,520 --> 01:03:35,200
to get a second opinion...
1012
01:03:35,200 --> 01:03:37,760
And then here are the pads
of the toes.
1013
01:03:37,760 --> 01:03:40,400
We see all those
beautiful scales lined up.
1014
01:03:40,400 --> 01:03:42,720
..from Professor Paul Barrett,
1015
01:03:42,720 --> 01:03:45,960
an expert
in ornithischian dinosaurs
1016
01:03:45,960 --> 01:03:48,840
from the Natural History Museum.
1017
01:03:48,840 --> 01:03:51,120
So what do you think
this might be?
1018
01:03:51,120 --> 01:03:54,000
When we look at the leg,
it has claws,
1019
01:03:54,000 --> 01:03:58,600
like the claws we see in small,
agile, bipedal, running dinosaurs
1020
01:03:58,600 --> 01:04:01,000
that are plant-eaters.
1021
01:04:01,000 --> 01:04:03,000
We can rule out things
like triceratops,
1022
01:04:03,000 --> 01:04:05,400
partly just because
it's not big and stocky.
1023
01:04:05,400 --> 01:04:08,600
And the proportions of those legs
are also different
1024
01:04:08,600 --> 01:04:10,880
from some of
the other plant-eaters we see,
1025
01:04:10,880 --> 01:04:12,760
in that they have
this rather long ankle
1026
01:04:12,760 --> 01:04:16,120
and shin, compared with its
thighbone.
1027
01:04:16,120 --> 01:04:18,160
So as we narrow
those possibilities down,
1028
01:04:18,160 --> 01:04:19,640
what we're left with, probably,
1029
01:04:19,640 --> 01:04:21,480
is an animal called a thescelosaur.
1030
01:04:21,480 --> 01:04:23,000
SQUEAKS
1031
01:04:30,440 --> 01:04:33,160
Thescelosaurs lived next to rivers
1032
01:04:33,160 --> 01:04:36,200
where there was plenty
of rich vegetation to feed on.
1033
01:04:38,680 --> 01:04:40,960
They had leaf-shaped teeth,
1034
01:04:40,960 --> 01:04:43,000
common amongst herbivores,
1035
01:04:43,000 --> 01:04:45,080
and claws
on their short front limbs -
1036
01:04:45,080 --> 01:04:47,240
excellent for digging.
1037
01:04:57,600 --> 01:04:58,960
SQUEAKS
1038
01:05:01,000 --> 01:05:02,880
CRUNCHING
1039
01:05:04,680 --> 01:05:07,880
But how did
Robert's thescelosaur die?
1040
01:05:09,480 --> 01:05:12,400
Could it have been killed
by another dinosaur?
1041
01:05:12,400 --> 01:05:14,120
It's a possibility.
1042
01:05:14,120 --> 01:05:16,200
This is a relatively agile animal.
1043
01:05:16,200 --> 01:05:18,360
And that turn of speed
would've been
1044
01:05:18,360 --> 01:05:22,360
its primary defence against the
large predators living alongside it.
1045
01:05:27,760 --> 01:05:31,640
So, to escape a hungry T-rex,
1046
01:05:31,640 --> 01:05:34,040
a thescelosaur's first line
of defence...
1047
01:05:34,040 --> 01:05:35,360
BARKS
1048
01:05:35,360 --> 01:05:36,880
..would've been to run.
1049
01:05:39,560 --> 01:05:43,800
But it may have had
another defensive trick.
1050
01:05:47,600 --> 01:05:49,440
ROARS
1051
01:05:52,280 --> 01:05:53,840
Living next to rivers,
1052
01:05:53,840 --> 01:05:57,640
it's possible thescelosaurs
were able to swim.
1053
01:06:11,040 --> 01:06:13,480
It doesn't seem to me
like there is any evidence
1054
01:06:13,480 --> 01:06:15,160
that this animal was predated -
1055
01:06:15,160 --> 01:06:17,800
none of the obvious tooth marks
1056
01:06:17,800 --> 01:06:19,960
or leftover bits
of carnivore teeth
1057
01:06:19,960 --> 01:06:22,040
to suggest it's been eaten.
1058
01:06:22,040 --> 01:06:24,600
So how do you think it died?
1059
01:06:24,600 --> 01:06:27,560
It didn't have any particularly
nasty diseases when it died,
1060
01:06:27,560 --> 01:06:30,280
as we can see
that the bones look OK.
1061
01:06:30,280 --> 01:06:32,240
So this is an animal
that was probably living
1062
01:06:32,240 --> 01:06:35,480
and healthy at the time
that this happened to it.
1063
01:06:35,480 --> 01:06:40,600
Could this be a victim
of the meteor strike?
1064
01:06:40,600 --> 01:06:42,000
I think it's entirely possible.
1065
01:06:42,000 --> 01:06:44,200
This is actually a shoulder bone,
1066
01:06:44,200 --> 01:06:46,160
and this bone in a living animal
1067
01:06:46,160 --> 01:06:48,200
would actually be way over here.
1068
01:06:48,200 --> 01:06:50,000
And similarly, this little bone here
1069
01:06:50,000 --> 01:06:52,800
would've been from about
maybe a third of the way
1070
01:06:52,800 --> 01:06:54,760
along the tail, maybe halfway down.
1071
01:06:54,760 --> 01:06:59,320
So somehow these two bones
have been telescoped together.
1072
01:06:59,320 --> 01:07:01,760
So maybe this animal's
been tumbled around.
1073
01:07:01,760 --> 01:07:04,400
We've ruled out
a lot of other possible
1074
01:07:04,400 --> 01:07:06,360
causes of death for this animal.
1075
01:07:06,360 --> 01:07:09,320
So it could well be
that this is an animal
1076
01:07:09,320 --> 01:07:11,080
that was there, being tumbled around
1077
01:07:11,080 --> 01:07:12,760
in its death throes, in that river,
1078
01:07:12,760 --> 01:07:14,520
as a result of the asteroid impact.
1079
01:07:15,880 --> 01:07:18,440
Well, it is exactly analogous
1080
01:07:18,440 --> 01:07:21,600
to those human bodies
found in Pompeii.
1081
01:07:21,600 --> 01:07:24,840
It's very similar in terms of
you get that quick entombment.
1082
01:07:24,840 --> 01:07:26,880
Yes. And it's almost as evocative.
1083
01:07:26,880 --> 01:07:29,160
That's absolutely true.
1084
01:07:29,160 --> 01:07:31,440
You've got literally
the blink of an eye
1085
01:07:31,440 --> 01:07:33,320
at the end of the Cretaceous,
1086
01:07:33,320 --> 01:07:35,480
snapped up into history,
and there it is,
1087
01:07:35,480 --> 01:07:38,920
ready to be dug up. Wow.
1088
01:07:35,480 --> 01:07:38,920
LAUGHS
1089
01:07:50,320 --> 01:07:52,600
After years of investigation,
1090
01:07:52,600 --> 01:07:54,880
Robert has found out a great deal
1091
01:07:54,880 --> 01:07:57,000
about the creatures
which lived at Tanis,
1092
01:07:57,000 --> 01:08:01,600
and he knows that many of them were
alive on that fateful day
1093
01:08:01,600 --> 01:08:04,680
when the asteroid
devastated our planet.
1094
01:08:05,800 --> 01:08:08,000
But how exactly did they die?
1095
01:08:09,000 --> 01:08:12,840
Robert's finds now allow us
to tell the story of that day
1096
01:08:12,840 --> 01:08:15,320
and finally answer that question.
1097
01:08:19,640 --> 01:08:22,600
One of the most important days
in Earth's history
1098
01:08:22,600 --> 01:08:26,520
probably started much like any
other late spring morning.
1099
01:08:31,640 --> 01:08:36,520
We know the season because Robert
found fossils of young fish that
1100
01:08:36,520 --> 01:08:39,200
died at the size they reach
at that time of year.
1101
01:08:39,200 --> 01:08:41,840
This agrees
with evidence already found
1102
01:08:41,840 --> 01:08:43,880
by other scientists.
1103
01:08:46,320 --> 01:08:49,960
Perhaps this day, that would end
with so much death,
1104
01:08:49,960 --> 01:08:52,560
began with something different.
1105
01:08:54,360 --> 01:08:55,960
A new life.
1106
01:08:58,040 --> 01:09:00,400
SQUEAKING
1107
01:09:06,200 --> 01:09:08,080
SQUAWKS
1108
01:09:19,440 --> 01:09:22,760
No-one can be certain
of the exact timings of the day
1109
01:09:22,760 --> 01:09:25,880
when the asteroid collided
with our planet.
1110
01:09:25,880 --> 01:09:30,240
But it's estimated that within
just 40 minutes of the impact,
1111
01:09:30,240 --> 01:09:32,800
the consequences
for the creatures of Tanis
1112
01:09:32,800 --> 01:09:34,360
would have been profound.
1113
01:09:38,480 --> 01:09:39,880
Based on Robert's finds
1114
01:09:39,880 --> 01:09:42,680
and the latest evidence
from other scientists,
1115
01:09:42,680 --> 01:09:46,160
this is how the catastrophe
might have unfolded.
1116
01:09:48,840 --> 01:09:52,360
The asteroid is around
seven miles across,
1117
01:09:52,360 --> 01:09:54,240
bigger than Mount Everest...
1118
01:09:55,800 --> 01:10:00,280
..and travelling at close
to 45,000mph.
1119
01:10:04,080 --> 01:10:06,280
The impact causes an explosion
1120
01:10:06,280 --> 01:10:10,440
bigger than a billion
Hiroshima atomic bombs.
1121
01:10:17,720 --> 01:10:20,600
At Tanis,
almost 2,000 miles away...
1122
01:10:22,200 --> 01:10:24,320
..it's completely silent.
1123
01:10:28,320 --> 01:10:30,240
But at the impact site...
1124
01:10:32,560 --> 01:10:34,480
..the asteroid vaporises.
1125
01:10:36,360 --> 01:10:38,880
More than three trillion
tonnes of rock
1126
01:10:38,880 --> 01:10:40,800
are ejected into space
1127
01:10:40,800 --> 01:10:43,440
in a blast
of super-heated violence.
1128
01:10:48,240 --> 01:10:51,160
Winds higher than 600mph.
1129
01:10:52,640 --> 01:10:57,320
A colossal earthquake, followed
by a ring of massive tsunamis.
1130
01:11:03,080 --> 01:11:05,440
RUMBLING
1131
01:11:05,440 --> 01:11:07,800
ANIMAL CALLS
1132
01:11:07,800 --> 01:11:09,800
All the while,
the creatures at Tanis
1133
01:11:09,800 --> 01:11:11,680
go about their business...
1134
01:11:11,680 --> 01:11:13,800
CACOPHONY OF
ANIMAL NOISES
1135
01:11:15,680 --> 01:11:18,120
..just like any other day.
1136
01:11:18,120 --> 01:11:21,160
COOING
1137
01:11:21,160 --> 01:11:23,080
CLICKING
1138
01:11:23,080 --> 01:11:24,440
WARBLES
1139
01:11:29,600 --> 01:11:32,080
SNEEZES
1140
01:11:32,080 --> 01:11:33,520
THUNDER RUMBLES
1141
01:11:35,120 --> 01:11:36,160
SQUAWKS
1142
01:11:36,160 --> 01:11:38,880
The evidence suggests
that baby pterosaurs
1143
01:11:38,880 --> 01:11:42,360
emerge from the egg
ready to fend for themselves.
1144
01:11:45,000 --> 01:11:46,880
And that includes...
1145
01:11:49,480 --> 01:11:50,880
..flying?
1146
01:11:52,360 --> 01:11:53,960
Well, almost.
1147
01:12:02,600 --> 01:12:06,840
Elsewhere, as the devastation
spreads out across North America
1148
01:12:06,840 --> 01:12:08,160
towards Tanis...
1149
01:12:09,800 --> 01:12:12,920
..dinosaurs and creatures
of all shapes and sizes
1150
01:12:12,920 --> 01:12:15,360
are obliterated by the blast.
1151
01:12:26,800 --> 01:12:30,320
At Tanis, for a few more
precious minutes,
1152
01:12:30,320 --> 01:12:32,040
life carries on as usual.
1153
01:12:34,120 --> 01:12:36,320
But the clock is ticking.
1154
01:12:43,480 --> 01:12:44,680
GRUNTING
1155
01:12:45,720 --> 01:12:48,560
DEEP BELLOWING
1156
01:12:49,840 --> 01:12:53,600
The blast from the impact
never reaches Tanis,
1157
01:12:53,600 --> 01:12:56,120
but seismic shock waves do.
1158
01:13:00,840 --> 01:13:02,680
RUMBLING
1159
01:13:04,200 --> 01:13:06,280
CHIRPS
1160
01:13:09,200 --> 01:13:11,200
They are far more powerful
1161
01:13:11,200 --> 01:13:13,640
than any earthquake
ever recorded.
1162
01:13:16,640 --> 01:13:20,720
DEEP BELLOWING
1163
01:13:20,720 --> 01:13:22,240
SHRIEKING
1164
01:13:22,240 --> 01:13:25,680
The thescelosaur might head
for a place of safety...
1165
01:13:30,440 --> 01:13:32,800
..but seismic waves
are now slowly shaking
1166
01:13:32,800 --> 01:13:37,200
the whole region, causing water
to slosh and churn.
1167
01:13:42,520 --> 01:13:45,600
At Tanis,
strange currents in the river
1168
01:13:45,600 --> 01:13:48,240
give a hint
of what is still to come.
1169
01:13:54,120 --> 01:13:55,760
THUNDER CRACKS
1170
01:13:57,240 --> 01:14:00,120
Next, it begins to rain.
1171
01:14:00,120 --> 01:14:02,240
PATTERING
1172
01:14:02,240 --> 01:14:05,480
Ejecta spherules
are falling back to Earth.
1173
01:14:13,360 --> 01:14:16,280
As the spherules
begin their fall...
1174
01:14:17,400 --> 01:14:20,720
..friction heats them
until they're red hot.
1175
01:14:27,160 --> 01:14:30,560
Then the heat transfers
to the air.
1176
01:14:32,040 --> 01:14:34,320
Temperatures rise with every second.
1177
01:14:42,760 --> 01:14:46,080
As the heat builds,
the creatures of Tanis
1178
01:14:46,080 --> 01:14:47,720
are fighting for their lives.
1179
01:14:49,480 --> 01:14:51,280
ROARS
1180
01:14:52,840 --> 01:14:55,320
And then, as seismic waves
1181
01:14:55,320 --> 01:14:58,120
continue to slowly rock
the whole region...
1182
01:15:01,640 --> 01:15:04,960
..a violent surge wave
ten metres high
1183
01:15:04,960 --> 01:15:07,280
rushes up the Tanis river.
1184
01:15:26,200 --> 01:15:28,680
Surviving the turbulence
of the surge
1185
01:15:28,680 --> 01:15:31,840
is a challenge
even for the best swimmers.
1186
01:15:43,760 --> 01:15:47,600
Then, the powerful rocking
of the river system
1187
01:15:47,600 --> 01:15:51,240
slowly begins to draw the water
back the way it came.
1188
01:16:00,880 --> 01:16:02,640
Swimming may have saved
1189
01:16:02,640 --> 01:16:05,320
the thescelosaur in the past,
1190
01:16:05,320 --> 01:16:07,120
but not this time.
1191
01:16:12,720 --> 01:16:15,320
A large, robust animal
like a T-rex
1192
01:16:15,320 --> 01:16:17,400
might have survived the surge.
1193
01:16:22,880 --> 01:16:25,240
As might a hard-shelled reptile.
1194
01:16:26,920 --> 01:16:29,760
But there is much more to come.
1195
01:16:29,760 --> 01:16:34,880
As billions of tonnes of superheated
spherules continue to fall,
1196
01:16:34,880 --> 01:16:37,200
the atmosphere gets even hotter...
1197
01:16:39,640 --> 01:16:43,760
..igniting dead leaves
and sparking wildfires.
1198
01:16:50,080 --> 01:16:51,680
Earthquakes,
1199
01:16:51,680 --> 01:16:53,640
fire...
1200
01:16:55,760 --> 01:16:57,240
..devastation.
1201
01:16:59,760 --> 01:17:01,800
Little would survive for long,
1202
01:17:01,800 --> 01:17:03,640
on land..
1203
01:17:03,640 --> 01:17:05,880
ROARS
1204
01:17:08,280 --> 01:17:10,080
..or in the air.
1205
01:17:13,080 --> 01:17:15,400
SHRIEKS
1206
01:17:16,520 --> 01:17:18,280
GRUNTS
1207
01:17:30,400 --> 01:17:34,280
As the air reaches the temperature
of an industrial oven...
1208
01:17:37,240 --> 01:17:39,320
..those that live
deep underground
1209
01:17:39,320 --> 01:17:40,880
may have a better chance.
1210
01:17:48,840 --> 01:17:52,360
As the slow sloshing of
the river system continues...
1211
01:17:55,280 --> 01:17:57,600
..another powerful surge hits.
1212
01:18:18,480 --> 01:18:21,080
There is no escaping
the destruction.
1213
01:18:24,240 --> 01:18:27,280
For many of the creatures
of Tanis,
1214
01:18:27,280 --> 01:18:29,680
their stories end underwater.
1215
01:18:45,280 --> 01:18:49,520
In less than two hours,
the world has changed forever.
1216
01:18:56,200 --> 01:18:58,960
The mud the surge waves leave behind
1217
01:18:58,960 --> 01:19:02,960
will gradually turn into the thick
layer of crumbly rock
1218
01:19:02,960 --> 01:19:05,880
entombing the creatures
which died here...
1219
01:19:08,760 --> 01:19:11,880
..until 66 million years later,
1220
01:19:11,880 --> 01:19:14,200
when they're finally unearthed.
1221
01:19:23,600 --> 01:19:27,920
Robert's finds have helped us
understand in remarkable detail
1222
01:19:27,920 --> 01:19:29,600
what happened at Tanis
1223
01:19:29,600 --> 01:19:33,120
in the minutes
after the asteroid impact.
1224
01:19:33,120 --> 01:19:35,280
But what about
the rest of the world?
1225
01:19:38,400 --> 01:19:41,240
The impact triggered catastrophic
events
1226
01:19:41,240 --> 01:19:44,120
such as earthquakes all over
the planet.
1227
01:19:45,760 --> 01:19:48,240
And as spherules
continued to fall...
1228
01:19:51,280 --> 01:19:54,560
..wildfires may have sprung up
around the globe.
1229
01:19:57,320 --> 01:20:00,600
As that horrific day
drew to a close,
1230
01:20:00,600 --> 01:20:04,400
many of the world's dinosaurs
were already dead.
1231
01:20:09,960 --> 01:20:14,440
Research shows that the angle
at which the asteroid hit
1232
01:20:14,440 --> 01:20:17,440
and the sulphur-rich rocks
at the impact site
1233
01:20:17,440 --> 01:20:19,720
amplified the devastation.
1234
01:20:19,720 --> 01:20:21,680
Billions of tonnes of sulphur
1235
01:20:21,680 --> 01:20:23,960
were ejected into the atmosphere,
1236
01:20:23,960 --> 01:20:25,840
blocking the sunlight.
1237
01:20:27,960 --> 01:20:32,800
Without light, most plants died,
and food became scarce.
1238
01:20:34,600 --> 01:20:37,280
As the weeks and months passed,
1239
01:20:37,280 --> 01:20:40,680
any dinosaur left alive
would've died of hunger.
1240
01:20:43,520 --> 01:20:46,240
In the oceans, it was the same.
1241
01:20:46,240 --> 01:20:49,560
Nearly all of the world's
plankton disappeared,
1242
01:20:49,560 --> 01:20:53,600
leading to the starvation
of most marine creatures.
1243
01:20:55,200 --> 01:20:58,720
It's thought that the nuclear
winter that followed
1244
01:20:58,720 --> 01:21:01,360
caused a global temperature drop
1245
01:21:01,360 --> 01:21:04,320
of at least
25 degrees centigrade.
1246
01:21:04,320 --> 01:21:08,320
The fossil record tells us that this
huge change in climate
1247
01:21:08,320 --> 01:21:12,200
marked the disappearance of three
quarters of all species,
1248
01:21:12,200 --> 01:21:14,040
including the dinosaurs.
1249
01:21:16,520 --> 01:21:21,080
The planet was in semi-darkness
for around a decade,
1250
01:21:21,080 --> 01:21:24,280
as dust and soot
slowly fell to Earth.
1251
01:21:26,080 --> 01:21:28,440
But then came something wonderful.
1252
01:21:30,320 --> 01:21:32,040
A new beginning.
1253
01:21:36,440 --> 01:21:39,160
Once the dust cleared
from the atmosphere
1254
01:21:39,160 --> 01:21:40,840
and the sunlight returned...
1255
01:21:42,360 --> 01:21:46,000
..plant life was gradually restored,
1256
01:21:46,000 --> 01:21:47,960
led by ferns,
1257
01:21:47,960 --> 01:21:52,160
the spores of which had lain
dormant deep underground,
1258
01:21:52,160 --> 01:21:56,160
and the world began
to turn green once more.
1259
01:21:58,360 --> 01:22:00,480
But what about the animals?
1260
01:22:03,160 --> 01:22:06,520
Back at Tanis,
Robert has unearthed something
1261
01:22:06,520 --> 01:22:09,320
that could have helped save
some of the creatures
1262
01:22:09,320 --> 01:22:11,920
from the devastating fires.
1263
01:22:11,920 --> 01:22:13,560
We saw a little thing
poking out,
1264
01:22:13,560 --> 01:22:15,560
so we kind of followed it back.
1265
01:22:15,560 --> 01:22:17,600
And I'm so glad that we did,
1266
01:22:17,600 --> 01:22:19,920
because what we have here
is a fossil burrow
1267
01:22:19,920 --> 01:22:22,680
from an animal 66 million years ago.
1268
01:22:24,280 --> 01:22:26,680
The only animals that
would've been around back then
1269
01:22:26,680 --> 01:22:28,960
that would likely build
a burrow like this
1270
01:22:28,960 --> 01:22:31,880
would be the small mammals,
roughly ferret-sized,
1271
01:22:31,880 --> 01:22:34,440
and also some reptiles.
1272
01:22:34,440 --> 01:22:38,680
If it is from a mammal,
this is sort of a window
1273
01:22:38,680 --> 01:22:41,560
into the lifestyle of some of
our oldest ancestors out here.
1274
01:22:42,600 --> 01:22:44,640
This guy would've burrowed
sideways,
1275
01:22:44,640 --> 01:22:46,080
right into the river bank.
1276
01:22:47,400 --> 01:22:49,480
We actually have
some scratch marks on there
1277
01:22:49,480 --> 01:22:51,680
from the interior
when they were digging it,
1278
01:22:51,680 --> 01:22:54,560
going back,
and he would've lived back here
1279
01:22:54,560 --> 01:22:56,360
and sought shelter
from the dinosaurs
1280
01:22:56,360 --> 01:22:58,640
cos they just did not
want to get eaten.
1281
01:23:05,000 --> 01:23:07,280
Burrows are part of the reason
1282
01:23:07,280 --> 01:23:10,320
that mammals survived
the great extinction.
1283
01:23:12,000 --> 01:23:13,880
During the nuclear winter,
1284
01:23:13,880 --> 01:23:16,080
a burrow would've provided warmth,
1285
01:23:16,080 --> 01:23:19,280
protection,
and a place to store food.
1286
01:23:26,520 --> 01:23:29,880
Mammals that survived
were resourceful omnivores,
1287
01:23:29,880 --> 01:23:33,680
and insects would've been
a plentiful source of food.
1288
01:23:39,360 --> 01:23:43,120
And they had another advantage -
their size.
1289
01:23:45,440 --> 01:23:49,240
If conditions are right,
many animal species get larger
1290
01:23:49,240 --> 01:23:52,200
as they evolve
over millions of years.
1291
01:23:52,200 --> 01:23:55,680
Take T-rex as an example.
1292
01:23:55,680 --> 01:23:58,960
This is a cast of the lower jaw
1293
01:23:58,960 --> 01:24:01,600
of a predecessor, called
gorgosaurus,
1294
01:24:01,600 --> 01:24:04,360
which lived
72 million years ago.
1295
01:24:04,360 --> 01:24:10,280
Whereas this is the cast
of the lower jaw of a T-rex,
1296
01:24:10,280 --> 01:24:12,880
which lived
five million years later.
1297
01:24:12,880 --> 01:24:16,800
Look at the difference in size.
1298
01:24:16,800 --> 01:24:18,200
But the bigger the creature,
1299
01:24:18,200 --> 01:24:20,760
the more energy they need
to stay alive.
1300
01:24:20,760 --> 01:24:24,600
So when catastrophe strikes
and food is scarce,
1301
01:24:24,600 --> 01:24:26,960
the largest tend to die out,
1302
01:24:26,960 --> 01:24:29,920
whilst the smallest
often survive.
1303
01:24:33,040 --> 01:24:34,960
That's one of the reasons
1304
01:24:34,960 --> 01:24:37,400
why many of the smaller mammals
1305
01:24:37,400 --> 01:24:40,200
lived through the great darkness.
1306
01:24:40,200 --> 01:24:42,240
And they weren't alone.
1307
01:24:44,760 --> 01:24:47,960
Robert's fossil turtle
may have been unlucky,
1308
01:24:47,960 --> 01:24:49,680
but many others survived.
1309
01:24:53,400 --> 01:24:56,000
As did crocodiles,
1310
01:24:56,000 --> 01:24:57,800
snakes,
1311
01:24:57,800 --> 01:25:00,720
and many fish species.
1312
01:25:00,720 --> 01:25:03,480
And as for the dinosaurs,
1313
01:25:03,480 --> 01:25:05,960
did the impact
really kill them all?
1314
01:25:05,960 --> 01:25:09,640
Well, this beautiful
fossilised feather
1315
01:25:09,640 --> 01:25:11,680
isn't from a bird,
1316
01:25:11,680 --> 01:25:13,840
but from a predatory dinosaur.
1317
01:25:13,840 --> 01:25:15,560
So we have to be careful
1318
01:25:15,560 --> 01:25:18,800
when we say
that dinosaurs are extinct,
1319
01:25:18,800 --> 01:25:22,880
because what we call birds
originally evolved
1320
01:25:22,880 --> 01:25:25,920
from the smallest
feathered dinosaurs.
1321
01:25:25,920 --> 01:25:28,160
So to be correct, we should say
1322
01:25:28,160 --> 01:25:32,120
all non-avian dinosaurs
are extinct.
1323
01:25:34,920 --> 01:25:37,080
Robert's finds have given us
1324
01:25:37,080 --> 01:25:39,400
a better idea
than ever before...
1325
01:25:41,000 --> 01:25:44,800
..about what happened on the day
that led to the extinction...
1326
01:25:46,840 --> 01:25:50,360
..of the largest beasts
ever to walk the Earth.
1327
01:25:53,760 --> 01:25:56,000
Dinosaurs were perhaps
1328
01:25:56,000 --> 01:25:59,440
some of nature's
most extraordinary creatures,
1329
01:25:59,440 --> 01:26:03,520
dominating the planet
for over 150 million years
1330
01:26:03,520 --> 01:26:05,480
before they became extinct.
1331
01:26:08,200 --> 01:26:11,040
But extinction
comes in different forms,
1332
01:26:11,040 --> 01:26:13,320
and many of the amazing creatures
1333
01:26:13,320 --> 01:26:16,760
and plants alive today
are also threatened.
1334
01:26:16,760 --> 01:26:19,760
It's possible that humanity
is having
1335
01:26:19,760 --> 01:26:22,120
as big an impact on the world
1336
01:26:22,120 --> 01:26:26,880
as the asteroid that ended
the age of the dinosaurs.
1337
01:26:26,880 --> 01:26:30,440
As human beings,
we are unique in our ability
1338
01:26:30,440 --> 01:26:33,520
to learn from the distant past.
1339
01:26:33,520 --> 01:26:38,640
Now we must use that ability
wisely and do our very best
1340
01:26:38,640 --> 01:26:41,040
to protect the millions of species
1341
01:26:41,040 --> 01:26:45,520
for whom, alongside us,
this planet is home.
97308
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