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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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something like
this little furry creature.
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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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…from triceratops…
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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 4 ½ billion-year history
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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…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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Re-sync: BLU DUAINE
blu.duaine@protonmail.com
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This landscape is full of fossils
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 in the past,
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or still does, 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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00:05:46,320 --> 00:05:49,880
Instead of rocky cliffs,
there were forests.
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And instead
of the life we know today…
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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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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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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.
87
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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…
98
00:07:02,720 --> 00:07:04,816
And there's more.
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I'm just going to go ahead and
plane down some of this rock.
100
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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.
103
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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.
105
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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.
111
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Look at that. That's amazing.
112
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Yeah, yeah, yeah, yeah, yeah.
That's what we want.
113
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OK. So it's coming
from this area here.
114
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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.
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00:08:08,760 --> 00:08:11,576
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.
123
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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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00:08:21,720 --> 00:08:24,216
you expect really, really hard
rocks and jackhammers
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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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this layer of rock is also
around a metre thick,
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which, along with
other unusual features, makes
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Robert think that something very
strange must have happened here.
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Maybe a flood or a mud flow,
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burying anything within it
in an instant.
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Oh, there's a beautiful…
Look at that one - beautiful.
135
00:08:58,400 --> 00:09:01,456
This could mean that anything
he finds in this layer
136
00:09:01,480 --> 00:09:04,176
would have been quickly entombed,
137
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like the bodies in
the volcanic ash of Pompeii.
138
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Robert knows from the geology
139
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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
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and could be so well preserved
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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.
151
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That is a critical part
of the story.
152
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Palaeontologists Dr David Burnham
153
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and Loren Gurche have been
digging with Robert for years.
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Oh, wow!
155
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See… see the brown? Yep.
156
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That might be a tubercle
right there.
157
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And it seems today is their
lucky day.
158
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Oh, my God! Look at that!
Look at that.
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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.
170
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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,
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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
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that this is from a triceratops.
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The brown colour contains
traces of organic material.
188
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So it might even be possible
from this
189
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to work out
which pigments were in it.
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Finding and studying
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such well-preserved fossils
as this
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helps palaeontologists build
193
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a much more detailed picture
of how these creatures lived.
194
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Combining this information
195
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with insights from scientists
around the world
196
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makes it possible to speculate
197
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about what life
in the Late Cretaceous
198
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might have been like.
199
00:12:23,760 --> 00:12:25,176
We know from bones
200
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that adult triceratops could
reach nine metres in length
201
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and three metres in height.
202
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Marks on the fossil also show us
203
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that this one was badly scarred.
204
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Triceratops were plant-eaters.
205
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Other fossils tell us
that they had sharp beaks
206
00:12:59,920 --> 00:13:03,896
and hundreds of teeth that enabled
them to shred tough plants
207
00:13:03,920 --> 00:13:05,800
such as these cycads.
208
00:13:15,640 --> 00:13:18,616
Almost all adult
triceratops fossils,
209
00:13:18,640 --> 00:13:21,880
including Robert's,
have been found on their own.
210
00:13:23,480 --> 00:13:26,416
So it's possible
that the adults were solitary,
211
00:13:26,440 --> 00:13:29,000
like modern-day male rhinos.
212
00:13:31,160 --> 00:13:33,376
So they were
probably territorial,
213
00:13:33,400 --> 00:13:35,640
chasing rivals away.
214
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And perhaps
marking their territories.
215
00:13:49,960 --> 00:13:52,256
If you weigh more
than an African elephant,
216
00:13:52,280 --> 00:13:54,360
there's not much
that can bother you…
217
00:13:58,960 --> 00:14:02,040
…except perhaps a little mammal.
218
00:14:18,560 --> 00:14:21,416
Robert found these jawbones
219
00:14:21,440 --> 00:14:24,816
in the fossilised burrow at Tanis.
220
00:14:24,840 --> 00:14:28,056
The shape of this tiny bone
and tooth
221
00:14:28,080 --> 00:14:31,376
means it's most likely come
from what's known
222
00:14:31,400 --> 00:14:34,456
as a pediomyid, an early mammal
223
00:14:34,480 --> 00:14:37,480
and a type of marsupial.
224
00:14:40,880 --> 00:14:44,176
Robert also discovered
fossilised nuts and seeds
225
00:14:44,200 --> 00:14:45,480
in the burrow.
226
00:14:46,800 --> 00:14:49,840
So we have an idea about
what it might have eaten.
227
00:14:57,560 --> 00:14:59,456
Robert's finds are adding
228
00:14:59,480 --> 00:15:01,936
to our knowledge
of the complex world
229
00:15:01,960 --> 00:15:05,056
at the very end
of the Late Cretaceous.
230
00:15:05,080 --> 00:15:08,496
And it's not just
the fossilised creatures.
231
00:15:08,520 --> 00:15:11,136
If you walk on damp sand,
232
00:15:11,160 --> 00:15:13,200
you'll leave a trace behind.
233
00:15:17,480 --> 00:15:18,520
A footprint.
234
00:15:19,920 --> 00:15:24,256
The same was true
66 million years ago.
235
00:15:24,280 --> 00:15:28,736
And very, very occasionally,
such traces were preserved.
236
00:15:28,760 --> 00:15:32,360
And that's exactly
what happened here at Tanis.
237
00:15:34,520 --> 00:15:36,856
You know, we won't foil a backside.
238
00:15:36,880 --> 00:15:38,936
Right, we'll just put…
Put plaster right on.
239
00:15:38,960 --> 00:15:40,096
That way you've got…
240
00:15:40,120 --> 00:15:42,616
Robert has discovered
a number of footprints.
241
00:15:42,640 --> 00:15:44,536
Yeah. Let's see.
242
00:15:44,560 --> 00:15:46,880
Looks like a good print. Yeah.
243
00:15:51,320 --> 00:15:53,896
Their shape gives him a clue
244
00:15:53,920 --> 00:15:56,520
as to what might have made them.
245
00:16:01,520 --> 00:16:02,816
If he's right,
246
00:16:02,840 --> 00:16:05,256
they were made by a winged creature,
247
00:16:05,280 --> 00:16:08,320
that might well have liked
a small mammal…
248
00:16:11,120 --> 00:16:12,320
…for lunch.
249
00:16:19,400 --> 00:16:21,856
The footprints are long and narrow
250
00:16:21,880 --> 00:16:23,440
with four toe prints.
251
00:16:24,840 --> 00:16:28,016
Two are slightly longer
than the others,
252
00:16:28,040 --> 00:16:31,000
and that suggests
they were made by…
253
00:16:33,640 --> 00:16:35,040
…a pterosaur.
254
00:16:44,280 --> 00:16:48,416
Pterosaurs are not dinosaurs,
but flying reptiles
255
00:16:48,440 --> 00:16:51,480
on a different branch
of the evolutionary tree.
256
00:17:05,800 --> 00:17:08,416
Male pterosaurs
usually had crests,
257
00:17:08,440 --> 00:17:10,216
while females didn't.
258
00:17:10,240 --> 00:17:13,840
So crests may have been
used in courtship displays.
259
00:17:23,400 --> 00:17:27,416
And we have an indication of
where females laid their eggs,
260
00:17:27,440 --> 00:17:31,336
because evidence suggests
one pterosaur laid hers
261
00:17:31,360 --> 00:17:35,080
in the soft, sandy banks
of the river at Tanis.
262
00:17:50,320 --> 00:17:53,256
And this is a fossilised egg
263
00:17:53,280 --> 00:17:56,200
of a pterosaur
that Robert found there.
264
00:17:57,640 --> 00:18:00,976
The only one ever discovered
in North America.
265
00:18:01,000 --> 00:18:03,376
If you look at it
with the naked eye,
266
00:18:03,400 --> 00:18:07,416
all you see
is a jumble of lines.
267
00:18:07,440 --> 00:18:10,416
But if you examine it
with the latest technology,
268
00:18:10,440 --> 00:18:14,496
you can find out
a wealth of information,
269
00:18:14,520 --> 00:18:16,696
from the chemistry of the bones
270
00:18:16,720 --> 00:18:18,696
to the composition of the shell.
271
00:18:18,720 --> 00:18:21,576
And that, in turn,
can tell us a lot about
272
00:18:21,600 --> 00:18:24,440
how these incredible creatures
lived.
273
00:18:30,440 --> 00:18:32,376
Robert has been given access
274
00:18:32,400 --> 00:18:36,440
to the Diamond Light Source
synchrotron in Oxfordshire.
275
00:18:38,160 --> 00:18:40,296
It's a very powerful research tool
276
00:18:40,320 --> 00:18:42,400
that acts like a giant microscope.
277
00:18:45,520 --> 00:18:49,176
By accelerating electrons
in this huge ring,
278
00:18:49,200 --> 00:18:51,256
the synchrotron creates
beams of light
279
00:18:51,280 --> 00:18:53,800
many times brighter than the sun.
280
00:19:00,400 --> 00:19:04,656
Robert and paleobiologist
Dr Victoria Egerton
281
00:19:04,680 --> 00:19:07,696
now want to turn that beam
onto the egg fossil
282
00:19:07,720 --> 00:19:11,136
to discover more
about its chemical make-up.
283
00:19:11,160 --> 00:19:13,776
We're pretty much lined up
on the skeleton,
284
00:19:13,800 --> 00:19:15,656
but we might have to move
the stage a little bit
285
00:19:15,680 --> 00:19:18,536
to get to the right part. Sure.
286
00:19:18,560 --> 00:19:23,616
Meanwhile, Robert can reveal
the creature inside.
287
00:19:23,640 --> 00:19:25,736
And this?
288
00:19:25,760 --> 00:19:28,976
Who made this wonderful thing?
289
00:19:29,000 --> 00:19:32,296
I got replicas of the bones
from inside that egg
290
00:19:32,320 --> 00:19:34,736
and I restored the remainder
291
00:19:34,760 --> 00:19:35,776
and put together
292
00:19:35,800 --> 00:19:38,136
what the skeleton would've
looked like when it hatched.
293
00:19:38,160 --> 00:19:40,216
That's how big the creature
would've been
294
00:19:40,240 --> 00:19:41,656
outside the egg, if it had hatched.
295
00:19:41,680 --> 00:19:46,656
So this is the baby.
How big was it going to grow?
296
00:19:46,680 --> 00:19:49,376
These very long neck vertebrae
here
297
00:19:49,400 --> 00:19:52,536
are what really gave part
of the story away to us,
298
00:19:52,560 --> 00:19:55,056
because those long bones
match very, very closely
299
00:19:55,080 --> 00:19:56,696
with the azhdarchid pterosaurs.
300
00:19:56,720 --> 00:19:58,376
That is the giant pterosaurs.
301
00:19:58,400 --> 00:20:00,496
Oh, they were the whoppers,
weren't they?
302
00:20:00,520 --> 00:20:03,576
I mean, what, 25 feet?
303
00:20:03,600 --> 00:20:05,096
Wingspan? Some of them.
304
00:20:05,120 --> 00:20:09,456
This probably had a wingspan,
maybe 15 feet, five metres.
305
00:20:09,480 --> 00:20:12,216
Well, it looks as though
it could take off, really.
306
00:20:12,240 --> 00:20:14,216
It's easy to picture
something like that
307
00:20:14,240 --> 00:20:16,376
just hatching out of the egg
and fluttering out,
308
00:20:16,400 --> 00:20:18,240
almost like a little bat.
309
00:20:23,120 --> 00:20:27,600
They've scanned the egg,
here and in America.
310
00:20:29,360 --> 00:20:31,880
Victoria has the results.
311
00:20:33,720 --> 00:20:36,936
So what have you learned
from the synchrotron image?
312
00:20:36,960 --> 00:20:39,336
What we have here is a chemical map
313
00:20:39,360 --> 00:20:43,176
of calcium directly within
the bones of this animal.
314
00:20:43,200 --> 00:20:47,296
That tells us that these bones
were already hardened.
315
00:20:47,320 --> 00:20:51,096
So it might be ready to fly
not long after it hatches.
316
00:20:51,120 --> 00:20:53,656
OK. Can you see any sign
of the shell,
317
00:20:53,680 --> 00:20:55,056
and what sort of shell was it?
318
00:20:55,080 --> 00:20:58,336
We can. What I can show you…
319
00:20:58,360 --> 00:20:59,736
Ah!
320
00:20:59,760 --> 00:21:02,816
…is we can see the rim
of the egg in sulphur.
321
00:21:02,840 --> 00:21:07,776
Does that tell you whether it was
a hard shell or a soft shell?
322
00:21:07,800 --> 00:21:09,376
We have been looking at this.
323
00:21:09,400 --> 00:21:14,576
We can see folding occurring,
and this unusual undulation.
324
00:21:14,600 --> 00:21:16,376
If it were a hard egg,
325
00:21:16,400 --> 00:21:19,296
we would expect splintered bits
and broken bits,
326
00:21:19,320 --> 00:21:21,416
just like a chicken egg.
327
00:21:21,440 --> 00:21:23,216
This helped to tell us
that it was soft.
328
00:21:23,240 --> 00:21:25,416
So it was perhaps like a turtle?
329
00:21:25,440 --> 00:21:26,736
Absolutely.
330
00:21:26,760 --> 00:21:29,256
That's not the case, is it,
with dinosaurs?
331
00:21:29,280 --> 00:21:32,336
Many dinosaurs laid
hard-shelled eggs. Yes.
332
00:21:32,360 --> 00:21:35,616
So this is a new discovery
about azhdarchid pterosaurs?
333
00:21:35,640 --> 00:21:37,976
Absolutely. This is something
334
00:21:38,000 --> 00:21:40,216
that we are confirming
for the first time.
335
00:21:40,240 --> 00:21:41,576
Huh!
336
00:21:41,600 --> 00:21:44,856
That flying pterosaurs
had eggs like turtles.
337
00:21:44,880 --> 00:21:45,936
Yes.
338
00:21:45,960 --> 00:21:48,576
Much more reptilianlike
than birdlike.
339
00:21:48,600 --> 00:21:50,936
And that can potentially
tell us more
340
00:21:50,960 --> 00:21:54,336
about the environment
in which these eggs were laid.
341
00:21:54,360 --> 00:21:56,160
How interesting. Yeah.
342
00:22:04,480 --> 00:22:08,376
Creatures that lay soft eggs
tend to bury them
343
00:22:08,400 --> 00:22:10,040
in order to protect them.
344
00:22:15,720 --> 00:22:18,256
So female pterosaurs
probably looked for
345
00:22:18,280 --> 00:22:21,520
places like Tanis
to lay their eggs…
346
00:22:24,200 --> 00:22:28,216
…because the sandy soil here
is just soft enough
347
00:22:28,240 --> 00:22:31,440
for the hatchling to dig itself out.
348
00:22:33,200 --> 00:22:36,696
Now the pterosaur
just has to make sure
349
00:22:36,720 --> 00:22:38,280
that the hole…
350
00:22:39,800 --> 00:22:41,280
…is perfect.
351
00:22:57,880 --> 00:22:59,440
Success!
352
00:23:00,920 --> 00:23:03,296
But it's not over yet.
353
00:23:03,320 --> 00:23:06,736
Pterosaurs had two ovaries,
354
00:23:06,760 --> 00:23:09,480
and they laid their eggs in pairs.
355
00:23:19,240 --> 00:23:21,256
Here on the sandbank,
356
00:23:21,280 --> 00:23:25,456
sandwiched between the river
and these glorious trees,
357
00:23:25,480 --> 00:23:28,456
life at Tanis
seemed to be thriving.
358
00:23:28,480 --> 00:23:30,456
Whoops!
359
00:23:30,480 --> 00:23:32,376
Never a dull moment.
360
00:23:32,400 --> 00:23:35,440
But all that was about to change.
361
00:23:42,760 --> 00:23:46,056
The chain of events that led to the
extinction of the dinosaurs
362
00:23:46,080 --> 00:23:51,200
began in the distant past,
deep in space.
363
00:23:55,640 --> 00:23:59,736
Most scientists think it all started
in a ring of dust,
364
00:23:59,760 --> 00:24:03,520
rocks, and debris
known as the asteroid belt.
365
00:24:06,760 --> 00:24:09,240
It's usually an uneventful place.
366
00:24:13,160 --> 00:24:16,296
But it's thought that many,
many millions of years ago,
367
00:24:16,320 --> 00:24:19,480
a rock was bumped
into a new orbit…
368
00:24:24,000 --> 00:24:27,960
…and diverted onto a collision
course with Planet Earth.
369
00:24:40,640 --> 00:24:43,416
Robert is building a vivid picture
370
00:24:43,440 --> 00:24:45,680
of Late Cretaceous life
at Tanis.
371
00:24:48,360 --> 00:24:52,080
And the team have found some more
well-preserved footprints.
372
00:24:53,400 --> 00:24:56,736
So these are animals that were
actually walking in the water?
373
00:24:56,760 --> 00:24:58,776
These guys would've been
essentially on
374
00:24:58,800 --> 00:25:00,296
a mushy river bank going down
375
00:25:00,320 --> 00:25:02,016
to drink at some point.
376
00:25:02,040 --> 00:25:05,176
You know, animals tend to
congregate around the rivers.
377
00:25:05,200 --> 00:25:07,920
This print is 30 centimetres long.
378
00:25:09,120 --> 00:25:11,456
So I think this is from
a type of dinosaur
379
00:25:11,480 --> 00:25:13,376
that we call a duck-billed dinosaur.
380
00:25:13,400 --> 00:25:17,016
And they would've been
very common in the Cretaceous.
381
00:25:17,040 --> 00:25:19,336
They ate the plants in the area
382
00:25:19,360 --> 00:25:21,880
and they got very large -
30 feet long.
383
00:25:23,520 --> 00:25:25,056
And there are more.
384
00:25:25,080 --> 00:25:28,816
This track, you see all the toes
are very well preserved.
385
00:25:28,840 --> 00:25:31,896
You even see a nail print
at the tips of the toes.
386
00:25:31,920 --> 00:25:34,216
So the little toenails
dug into the mud.
387
00:25:34,240 --> 00:25:35,480
I love this one.
388
00:25:40,200 --> 00:25:43,336
This is Robert's prized footprint.
389
00:25:43,360 --> 00:25:46,256
It has three toes,
390
00:25:46,280 --> 00:25:49,776
and it's longer than it is wide.
391
00:25:49,800 --> 00:25:54,376
So it's very likely to be
a carnivorous dinosaur.
392
00:25:54,400 --> 00:25:56,896
It's so well preserved
that you can see
393
00:25:56,920 --> 00:26:00,480
the mark left by
its sharp claw there.
394
00:26:01,720 --> 00:26:03,256
Hell Creek is well known
395
00:26:03,280 --> 00:26:07,200
for one carnivore in particular -
T-rex.
396
00:26:08,280 --> 00:26:12,696
This footprint is too small
for an adult T-rex,
397
00:26:12,720 --> 00:26:16,720
but it's possible that it was made
by a young one.
398
00:26:26,800 --> 00:26:30,536
Robert also found this at Tanis -
399
00:26:30,560 --> 00:26:33,016
the crown of a tooth.
400
00:26:33,040 --> 00:26:37,016
Its shape and its serrated edge
401
00:26:37,040 --> 00:26:39,416
are indications that it comes
402
00:26:39,440 --> 00:26:41,200
from an adult T-rex.
403
00:27:06,600 --> 00:27:09,216
Bite marks found on T-rex bones
404
00:27:09,240 --> 00:27:12,240
show that they ate other T-rexes.
405
00:27:13,880 --> 00:27:16,560
And a youngster
would make an easy catch.
406
00:27:22,080 --> 00:27:23,920
But not this time.
407
00:27:33,280 --> 00:27:36,536
Very few footprints
are preserved as fossils
408
00:27:36,560 --> 00:27:38,416
in Hell Creek.
409
00:27:38,440 --> 00:27:40,736
So if you find several
in one place,
410
00:27:40,760 --> 00:27:42,376
as Robert has done,
411
00:27:42,400 --> 00:27:43,936
it's a reasonable assumption
412
00:27:43,960 --> 00:27:47,360
that there would've been
many more nearby.
413
00:27:50,680 --> 00:27:53,376
And that supports the idea
414
00:27:53,400 --> 00:27:58,096
that dinosaurs and pterosaurs
were thriving at Tanis
415
00:27:58,120 --> 00:28:00,200
shortly before the impact.
416
00:28:07,720 --> 00:28:09,280
And if they were thriving…
417
00:28:12,000 --> 00:28:15,680
…they must have been reproducing.
418
00:28:22,320 --> 00:28:25,296
Fossils from dinosaurs
similar to T-rex
419
00:28:25,320 --> 00:28:28,496
show they may have laid
around 20 eggs
420
00:28:28,520 --> 00:28:30,520
in a circular nest.
421
00:28:36,080 --> 00:28:38,496
It's possible that, like crocodiles,
422
00:28:38,520 --> 00:28:41,920
they partly covered their eggs
to keep them warm.
423
00:28:57,480 --> 00:29:00,600
For one T-rex, a misfortune.
424
00:29:07,600 --> 00:29:10,320
But for all dinosaurs…
425
00:29:11,520 --> 00:29:14,560
…a disaster was looming.
426
00:29:27,560 --> 00:29:31,960
Deep in space,
the asteroid was approaching.
427
00:29:36,680 --> 00:29:38,656
Its journey would take it through
the orbit
428
00:29:38,680 --> 00:29:41,480
of our neighbouring planet, Mars.
429
00:29:47,120 --> 00:29:48,936
Had the two collided,
430
00:29:48,960 --> 00:29:52,040
a catastrophe on Earth
would've been avoided.
431
00:30:00,880 --> 00:30:02,800
But it was not to be…
432
00:30:04,360 --> 00:30:07,040
…and Earth's fate was sealed.
433
00:30:20,800 --> 00:30:22,776
As Robert's dig continues,
434
00:30:22,800 --> 00:30:24,856
his vision of what happened at Tanis
435
00:30:24,880 --> 00:30:27,720
is finally starting to come
together.
436
00:30:29,720 --> 00:30:32,536
It seems the sandbank was full
of life.
437
00:30:32,560 --> 00:30:35,056
T-rex, triceratops,
438
00:30:35,080 --> 00:30:36,296
little mammals,
439
00:30:36,320 --> 00:30:40,216
alongside the footprints of
other dinosaurs and pterosaurs,
440
00:30:40,240 --> 00:30:42,280
all in a very small area.
441
00:30:44,080 --> 00:30:46,016
You see the scales?
442
00:30:46,040 --> 00:30:48,056
I do. Oh, my God.
443
00:30:48,080 --> 00:30:50,320
That excites me just looking at it!
444
00:30:52,200 --> 00:30:55,800
Then Robert finds
something truly remarkable.
445
00:30:59,120 --> 00:31:01,816
See the cracks already forming?
Look at that.
446
00:31:01,840 --> 00:31:04,736
So we're going to have to really
monitor that before we glue it.
447
00:31:04,760 --> 00:31:07,096
Cos this is getting vulnerable
now.
448
00:31:07,120 --> 00:31:09,560
An almost complete creature.
449
00:31:12,680 --> 00:31:15,040
To get this block out,
we're freezing it.
450
00:31:21,680 --> 00:31:24,600
Robert is about to attempt
something tricky.
451
00:31:26,440 --> 00:31:29,000
Steady… Let's go.
452
00:31:30,880 --> 00:31:33,856
To get the fossil out
in one piece, they're trying
453
00:31:33,880 --> 00:31:36,336
to freeze it using liquid nitrogen
454
00:31:36,360 --> 00:31:39,520
at almost 200 degrees below zero.
455
00:31:45,320 --> 00:31:46,680
Watch your footing.
456
00:31:47,960 --> 00:31:50,096
Loren, I'm worried
about brittleness here.
457
00:31:50,120 --> 00:31:53,440
Get that hammer. Give this a couple
whacks with the hammer.
458
00:31:55,080 --> 00:31:58,040
OK. Move over five centimetres.
Good.
459
00:32:01,240 --> 00:32:04,816
It's cracked loose. Yep.
OK. It's loose.
460
00:32:04,840 --> 00:32:07,336
So we have to get this out
in one piece.
461
00:32:07,360 --> 00:32:10,400
One, two, three.
462
00:32:12,000 --> 00:32:13,720
Yeehaw!
463
00:32:14,920 --> 00:32:16,880
Total success. Total success.
464
00:32:18,360 --> 00:32:21,016
This is a technique
used in archaeology
465
00:32:21,040 --> 00:32:23,456
for digging up human remains.
466
00:32:23,480 --> 00:32:25,616
We've got enough time
to work with the fossil
467
00:32:25,640 --> 00:32:27,336
and not damage it.
468
00:32:27,360 --> 00:32:29,840
And I couldn't be happier.
469
00:32:32,600 --> 00:32:34,880
And the creature Robert found?
470
00:32:36,360 --> 00:32:37,720
A turtle.
471
00:32:39,800 --> 00:32:43,656
This is the fossil
now it's been cleaned up.
472
00:32:43,680 --> 00:32:46,296
It's lying on its side.
473
00:32:46,320 --> 00:32:49,200
Here's the outline of its shell.
474
00:32:50,520 --> 00:32:54,216
The shape of the shell
and the scalloped edges here
475
00:32:54,240 --> 00:32:56,960
tell us that this was
a baenid turtle.
476
00:33:00,480 --> 00:33:03,736
Robert's baenid turtle
looks very similar
477
00:33:03,760 --> 00:33:05,536
to modern cooter turtles
478
00:33:05,560 --> 00:33:08,960
and lived in the same sort
of freshwater environment.
479
00:33:16,000 --> 00:33:19,160
For a turtle,
Tanis would've been ideal.
480
00:33:23,040 --> 00:33:25,760
Warm, shallow water.
481
00:33:28,000 --> 00:33:29,320
Plenty to eat.
482
00:33:34,120 --> 00:33:37,016
And lots of safe places
in which to warm up
483
00:33:37,040 --> 00:33:39,200
in the Late Cretaceous sunshine.
484
00:33:43,960 --> 00:33:47,536
The turtle fossil Robert found
is almost complete.
485
00:33:47,560 --> 00:33:50,416
This is the underside,
486
00:33:50,440 --> 00:33:55,496
and this brown material up here
is fossilised wood.
487
00:33:55,520 --> 00:33:59,216
It's the end of a stick that passes
right through its body
488
00:33:59,240 --> 00:34:02,416
and comes out just here.
489
00:34:02,440 --> 00:34:04,216
So the evidence points towards
490
00:34:04,240 --> 00:34:06,520
this turtle having been impaled.
491
00:34:09,240 --> 00:34:12,336
A violent end to one of
the many creatures found
492
00:34:12,360 --> 00:34:15,640
in the crumbly rock layer at Tanis.
493
00:34:16,680 --> 00:34:18,296
When I look at the animals
494
00:34:18,320 --> 00:34:20,936
and plants preserved
in the sediments of Tanis
495
00:34:20,960 --> 00:34:22,656
and the footprints beneath it,
496
00:34:22,680 --> 00:34:25,296
I see a picture of
a vibrant ecosystem,
497
00:34:25,320 --> 00:34:29,480
many different dinosaurs,
and a thriving, thriving place.
498
00:34:32,800 --> 00:34:34,696
After ten years of digging,
499
00:34:34,720 --> 00:34:37,816
there is now enough evidence
to piece together
500
00:34:37,840 --> 00:34:39,656
much of the story of Tanis
501
00:34:39,680 --> 00:34:42,320
and the creatures which lived here.
502
00:34:45,840 --> 00:34:49,416
Robert has found so many fossils,
it looks as if,
503
00:34:49,440 --> 00:34:51,816
even at the very end
of the Late Cretaceous,
504
00:34:51,840 --> 00:34:53,920
Tanis was bursting with life.
505
00:34:55,840 --> 00:34:59,656
Full of the giant reptiles
that had dominated the planet
506
00:34:59,680 --> 00:35:02,760
for more than 150 million years.
507
00:35:08,680 --> 00:35:11,856
It's impossible to know
how much longer
508
00:35:11,880 --> 00:35:13,520
their reign would've continued…
509
00:35:17,000 --> 00:35:21,480
…because all this was about to end.
510
00:35:42,720 --> 00:35:44,640
The asteroid hit…
511
00:35:48,320 --> 00:35:52,520
…in what is now the Yucatan
peninsula in Mexico.
512
00:35:55,360 --> 00:35:58,016
It's called the Chicxulub asteroid
513
00:35:58,040 --> 00:36:00,960
after the town nearest
to the centre of its crater.
514
00:36:19,160 --> 00:36:23,400
Any living thing within 900 miles
of the impact…
515
00:36:25,520 --> 00:36:28,360
…was destroyed by the blast.
516
00:36:33,240 --> 00:36:36,056
But what effect
did the impact have on Tanis,
517
00:36:36,080 --> 00:36:38,600
nearly 2,000 miles away?
518
00:36:48,320 --> 00:36:49,856
To find out,
519
00:36:49,880 --> 00:36:53,936
Robert is looking for clues
that might link Tanis
520
00:36:53,960 --> 00:36:57,160
to the actual day the asteroid hit.
521
00:37:03,160 --> 00:37:04,536
We've got some wood,
522
00:37:04,560 --> 00:37:07,536
and pressed up against this
and all intertangled,
523
00:37:07,560 --> 00:37:09,416
we've got the carcasses of fish.
524
00:37:09,440 --> 00:37:10,760
OK.
525
00:37:12,000 --> 00:37:13,936
That's a beautifully preserved
tail,
526
00:37:13,960 --> 00:37:16,856
so that fish is going to be
absolutely gorgeous.
527
00:37:16,880 --> 00:37:19,416
So part of the detail work
that we're doing right now
528
00:37:19,440 --> 00:37:21,056
is going in and checking out
529
00:37:21,080 --> 00:37:24,816
all the individual elements
in this mass death layer.
530
00:37:24,840 --> 00:37:28,056
Some of the evidence
he's found so far
531
00:37:28,080 --> 00:37:31,640
has been hidden inside
the fish themselves.
532
00:37:34,720 --> 00:37:37,856
In more ways than one, it literally
is an operation of a Cretaceous
533
00:37:37,880 --> 00:37:40,856
fish, so we're performing surgery
on this thing.
534
00:37:40,880 --> 00:37:43,920
Robert needs to open this
fish's skull.
535
00:37:45,640 --> 00:37:48,936
And very carefully,
we want to separate this
536
00:37:48,960 --> 00:37:50,440
from the rest of the fish.
537
00:37:51,680 --> 00:37:53,000
OK.
538
00:37:56,560 --> 00:37:58,856
Here we go.
539
00:37:58,880 --> 00:38:01,096
Opening up the fish.
540
00:38:01,120 --> 00:38:03,320
Got a nice ant
that made a home in there.
541
00:38:04,440 --> 00:38:06,096
And beautiful, look at that.
542
00:38:06,120 --> 00:38:09,136
OK, here we have
the gill bars of the fish.
543
00:38:09,160 --> 00:38:11,800
Those are the bars that hold
the filaments of the gills.
544
00:38:13,000 --> 00:38:14,696
And between the gill bars,
545
00:38:14,720 --> 00:38:16,776
all of these clusters
of round objects,
546
00:38:16,800 --> 00:38:18,600
those are the ejecta spherules.
547
00:38:19,640 --> 00:38:24,056
Ejecta spherules are tiny balls
that were once molten rock.
548
00:38:24,080 --> 00:38:26,656
They could be evidence
of what Robert suspects -
549
00:38:26,680 --> 00:38:28,256
that creatures here died
550
00:38:28,280 --> 00:38:31,000
on the day
of the asteroid strike.
551
00:38:32,200 --> 00:38:35,096
Those ejecta spherules
last saw the light of day
552
00:38:35,120 --> 00:38:38,120
when they were flying through
the air 66 billion years ago.
553
00:38:48,640 --> 00:38:52,216
After a large asteroid impact,
554
00:38:52,240 --> 00:38:54,976
a mix of vaporised and molten rock
555
00:38:55,000 --> 00:38:57,120
is propelled into space.
556
00:39:00,080 --> 00:39:01,616
There, it cools,
557
00:39:01,640 --> 00:39:04,840
solidifying
into tiny glass droplets.
558
00:39:06,400 --> 00:39:09,520
Some carry on deeper into space.
559
00:39:11,680 --> 00:39:15,000
But most are pulled back
to Earth by gravity.
560
00:39:22,520 --> 00:39:25,336
After a major asteroid hit,
561
00:39:25,360 --> 00:39:30,056
trillions of ejecta spherules
would fall from the sky.
562
00:39:30,080 --> 00:39:32,256
Then, over millions of years,
563
00:39:32,280 --> 00:39:35,256
pressure and chemical reactions
in the ground
564
00:39:35,280 --> 00:39:38,416
would turn most of them to clay.
565
00:39:38,440 --> 00:39:41,000
They'd look something like this.
566
00:39:42,080 --> 00:39:46,176
So finding spherules
in the gills of a fish,
567
00:39:46,200 --> 00:39:48,496
as Robert has done at Tanis,
568
00:39:48,520 --> 00:39:50,896
suggests the fish sucked them in
569
00:39:50,920 --> 00:39:53,696
while the spherules
were still falling.
570
00:39:53,720 --> 00:39:55,496
So these creatures could have died
571
00:39:55,520 --> 00:39:58,400
at the time of an asteroid impact.
572
00:40:03,800 --> 00:40:07,176
Once Robert begins to look
for ejecta spherules,
573
00:40:07,200 --> 00:40:08,856
he finds more and more,
574
00:40:08,880 --> 00:40:13,256
and realises the thick,
crumbly layer of rock at Tanis
575
00:40:13,280 --> 00:40:14,680
is full of them.
576
00:40:18,000 --> 00:40:20,216
I mean, this stuff is go…
Oh, my God, look at that one.
577
00:40:20,240 --> 00:40:22,200
These things are just gorgeous.
578
00:40:23,680 --> 00:40:25,056
Ejecta spherules like this
579
00:40:25,080 --> 00:40:27,680
give us a fingerprint
of where they came from.
580
00:40:29,320 --> 00:40:31,336
If these spherules were connected
581
00:40:31,360 --> 00:40:33,096
to the Chicxulub impact,
582
00:40:33,120 --> 00:40:36,216
then the whole crumbly layer
could be full of evidence
583
00:40:36,240 --> 00:40:39,896
of what happened on the day
the asteroid hit.
584
00:40:39,920 --> 00:40:41,176
That's a good one.
585
00:40:41,200 --> 00:40:43,576
Oh, is that a droplet right there?
586
00:40:43,600 --> 00:40:45,536
To see if that's the case,
587
00:40:45,560 --> 00:40:49,176
Robert needs to find a spherule
that hasn't turned to clay.
588
00:40:49,200 --> 00:40:52,976
Oh, my God,
that's a beautiful droplet.
589
00:40:53,000 --> 00:40:54,896
OK.
590
00:40:54,920 --> 00:40:58,016
The small pieces of orange material
591
00:40:58,040 --> 00:40:59,856
that Robert and Loren are digging up
592
00:40:59,880 --> 00:41:02,016
may be able to help.
593
00:41:02,040 --> 00:41:05,056
They're amber.
594
00:41:05,080 --> 00:41:07,536
If there was anything flying
through the air at that time,
595
00:41:07,560 --> 00:41:09,400
this is where it's going to get
caught.
596
00:41:11,720 --> 00:41:15,016
The amber they're collecting
was once sticky resin
597
00:41:15,040 --> 00:41:18,160
oozing out of
a Late Cretaceous tree trunk.
598
00:41:19,960 --> 00:41:22,336
It's a way for the tree
to protect itself,
599
00:41:22,360 --> 00:41:25,160
like a scab forming on a cut.
600
00:41:33,360 --> 00:41:36,176
Anything covered by the resin
would be frozen
601
00:41:36,200 --> 00:41:38,240
in an amber time capsule.
602
00:41:44,720 --> 00:41:47,056
If they find a spherule
preserved in amber,
603
00:41:47,080 --> 00:41:49,616
it could be analysed
604
00:41:49,640 --> 00:41:52,800
to see if it comes from
the Chicxulub asteroid impact.
605
00:41:55,880 --> 00:41:57,296
So during this batch,
606
00:41:57,320 --> 00:42:00,856
we were incredibly lucky
that we came across
607
00:42:00,880 --> 00:42:03,320
two completely unaltered spherules.
608
00:42:04,800 --> 00:42:08,176
This spherule could be
something amazing.
609
00:42:08,200 --> 00:42:12,840
Evidence preserved well enough
to analyse for chemical clues.
610
00:42:15,720 --> 00:42:17,096
If so,
611
00:42:17,120 --> 00:42:21,656
it could link Tanis directly
with the Chicxulub impact
612
00:42:21,680 --> 00:42:24,160
and the last day of the dinosaurs.
613
00:42:31,760 --> 00:42:34,376
To investigate, Robert is joined
614
00:42:34,400 --> 00:42:36,456
at the Diamond Light Source
615
00:42:36,480 --> 00:42:39,336
by Professor of Natural History
Phil Manning,
616
00:42:39,360 --> 00:42:41,656
of the University of Manchester.
617
00:42:41,680 --> 00:42:44,136
They've already run initial tests
618
00:42:44,160 --> 00:42:46,136
on the spherules in America.
619
00:42:46,160 --> 00:42:48,016
What have you found out so far?
620
00:42:48,040 --> 00:42:51,776
These little glass spherules,
these globs
621
00:42:51,800 --> 00:42:53,736
of molten material
from the impact site
622
00:42:53,760 --> 00:42:57,176
have a chemical signal that ties it
with where they came from.
623
00:42:57,200 --> 00:42:58,696
Cos when an asteroid hits,
624
00:42:58,720 --> 00:43:00,896
it melts the ground that it hits,
625
00:43:00,920 --> 00:43:03,136
but also that glass has
626
00:43:03,160 --> 00:43:05,736
a little bit of contamination
from the asteroid itself.
627
00:43:05,760 --> 00:43:09,136
And that gives you a unique
geochemical fingerprint.
628
00:43:09,160 --> 00:43:10,656
We can see once we've scanned it,
629
00:43:10,680 --> 00:43:13,496
and looking at spherules from
other sites in North Dakota,
630
00:43:13,520 --> 00:43:15,176
we can get a baseline
631
00:43:15,200 --> 00:43:19,416
for what the ejecta should look
like when it's related to
632
00:43:19,440 --> 00:43:21,096
the Chicxulub crater.
633
00:43:21,120 --> 00:43:22,656
And you can see each element here
634
00:43:22,680 --> 00:43:24,696
and the ratios of those elements.
635
00:43:24,720 --> 00:43:27,936
And when we look at Tanis,
it's a match.
636
00:43:27,960 --> 00:43:30,696
I mean, it perfectly overlays.
637
00:43:30,720 --> 00:43:33,696
So I think
this is powerful evidence
638
00:43:33,720 --> 00:43:37,296
supporting that Tanis
and Chicxulub are linked.
639
00:43:37,320 --> 00:43:39,336
And what do these findings mean
640
00:43:39,360 --> 00:43:42,256
for the rest of the fossils
that you're finding in Tanis?
641
00:43:42,280 --> 00:43:45,296
This data is key for the
entire site,
642
00:43:45,320 --> 00:43:47,576
because once you have that link
643
00:43:47,600 --> 00:43:50,336
and you know
what impact affected Tanis,
644
00:43:50,360 --> 00:43:53,976
then you essentially know
that every object in that site,
645
00:43:54,000 --> 00:43:56,856
all the animals and the plants
and everything buried
646
00:43:56,880 --> 00:43:58,216
in those sediments,
647
00:43:58,240 --> 00:44:00,880
are linked to the last day
of the Cretaceous.
648
00:44:02,800 --> 00:44:05,696
And the synchrotron here in the UK
649
00:44:05,720 --> 00:44:08,280
reveals something even more
remarkable.
650
00:44:10,680 --> 00:44:15,216
So this is showing
a beautiful synchrotron scan
651
00:44:15,240 --> 00:44:17,616
of the half of one spherule.
652
00:44:17,640 --> 00:44:20,456
The glass is
a good geochemical fingerprint,
653
00:44:20,480 --> 00:44:24,136
and we've got calcium, some iron,
654
00:44:24,160 --> 00:44:26,176
we've got strontium,
655
00:44:26,200 --> 00:44:27,976
but when we look at the
entire thing,
656
00:44:28,000 --> 00:44:30,936
we see something quite unexpected.
657
00:44:30,960 --> 00:44:33,096
That's your entire spherule.
658
00:44:33,120 --> 00:44:34,496
What's this?
659
00:44:34,520 --> 00:44:37,496
In this, we've got
a little bit of a nugget.
660
00:44:37,520 --> 00:44:39,736
There was a little particle
right there.
661
00:44:39,760 --> 00:44:40,976
So we scan it.
662
00:44:41,000 --> 00:44:43,456
And that's a lot of iron
in there.
663
00:44:43,480 --> 00:44:46,296
Over here, we've got chromium,
a big peak in chromium.
664
00:44:46,320 --> 00:44:49,376
Over here, we've got
a big peak in nickel.
665
00:44:49,400 --> 00:44:52,176
And the abundances
of iron, nickel and chromium,
666
00:44:52,200 --> 00:44:53,616
all together,
667
00:44:53,640 --> 00:44:56,336
that matches what you expect
to see in a meteoric body.
668
00:44:56,360 --> 00:44:59,336
That does not match what you
would normally have down here.
669
00:44:59,360 --> 00:45:02,936
So this is
extraterrestrial material?
670
00:45:02,960 --> 00:45:05,176
If you were to sort of grind up
671
00:45:05,200 --> 00:45:10,536
and stuff into a spherule
a piece of meteorite,
672
00:45:10,560 --> 00:45:12,416
that's what it's going to look
like.
673
00:45:12,440 --> 00:45:15,776
This could be a piece of
the Chicxulub asteroid.
674
00:45:15,800 --> 00:45:17,976
A piece of the bullet
that killed the dinosaurs.
675
00:45:18,000 --> 00:45:19,400
No!
676
00:45:25,960 --> 00:45:27,536
Robert could have found
677
00:45:27,560 --> 00:45:30,896
a fragment of the asteroid itself
in Tanis,
678
00:45:30,920 --> 00:45:36,656
physical evidence linking this site
to the Chicxulub impact.
679
00:45:36,680 --> 00:45:39,896
But Tanis is almost 2,000 miles away
680
00:45:39,920 --> 00:45:41,816
from where the asteroid hit.
681
00:45:41,840 --> 00:45:45,640
So exactly how did it cause
the creatures' deaths?
682
00:45:49,320 --> 00:45:51,416
To answer that question,
683
00:45:51,440 --> 00:45:55,120
Robert is searching
in the mass death layer.
684
00:45:57,760 --> 00:46:01,496
Right here, we've got
this intertangled mass of fish.
685
00:46:01,520 --> 00:46:04,016
There's one fish here,
another sturgeon goes this way,
686
00:46:04,040 --> 00:46:06,016
underneath the body of a paddlefish.
687
00:46:06,040 --> 00:46:07,896
There's another sturgeon
that goes this way,
688
00:46:07,920 --> 00:46:11,456
underneath this log, and continues
out the other side.
689
00:46:11,480 --> 00:46:13,616
And his head hit that log
690
00:46:13,640 --> 00:46:17,000
and has deflected downward
at a 90-degree angle.
691
00:46:19,000 --> 00:46:24,056
Robert uncovered a tangled mass of
fossilised creatures and logs
692
00:46:24,080 --> 00:46:26,256
surrounded by spherules
693
00:46:26,280 --> 00:46:30,696
and crushed together
in what's known as a logjam.
694
00:46:30,720 --> 00:46:33,496
He has a theory that
the creatures were swept
695
00:46:33,520 --> 00:46:36,976
to their death in some kind
of turbulent surge of water
696
00:46:37,000 --> 00:46:39,336
and quickly entombed in sediment,
697
00:46:39,360 --> 00:46:42,176
which is why
they're so well preserved.
698
00:46:42,200 --> 00:46:44,960
But what could have caused the wave?
699
00:46:48,800 --> 00:46:51,440
One theory is a tsunami.
700
00:46:55,600 --> 00:46:58,096
The asteroid hit at sea.
701
00:46:58,120 --> 00:46:59,656
Recent studies show
702
00:46:59,680 --> 00:47:03,720
it may have caused a wave
almost a mile high.
703
00:47:16,640 --> 00:47:19,496
The height of the wave
would've gradually reduced
704
00:47:19,520 --> 00:47:21,760
as it spread across the oceans.
705
00:47:23,240 --> 00:47:24,696
In the Late Cretaceous,
706
00:47:24,720 --> 00:47:27,816
North America was divided
by a narrow sea
707
00:47:27,840 --> 00:47:31,056
that's been called
the Western Interior Seaway.
708
00:47:31,080 --> 00:47:33,856
The tsunami could have
travelled up this,
709
00:47:33,880 --> 00:47:35,480
towards Tanis.
710
00:47:38,920 --> 00:47:41,680
But there's a big question
about the tsunami idea.
711
00:47:43,280 --> 00:47:45,216
The timing.
712
00:47:45,240 --> 00:47:48,136
Oh, which fish is that?
713
00:47:48,160 --> 00:47:51,256
That's a new…
It's a new contact. New one. Yeah.
714
00:47:51,280 --> 00:47:54,136
If a tsunami killed the fish,
715
00:47:54,160 --> 00:47:56,176
it would have to have hit
716
00:47:56,200 --> 00:47:58,000
while ejecta spherules
were falling…
717
00:47:59,320 --> 00:48:03,400
…because spherules were found
in the fish's gills.
718
00:48:05,120 --> 00:48:10,416
So how long after impact did
the spherules arrive at Tanis?
719
00:48:10,440 --> 00:48:12,896
Pretend this ball of foil
is a piece of ejecta
720
00:48:12,920 --> 00:48:16,056
coming out of the crater. It would
then go on an arc path,
721
00:48:16,080 --> 00:48:18,056
ballistic trajectory,
out of the crater
722
00:48:18,080 --> 00:48:20,640
and to wherever it lands -
in this case, Tanis.
723
00:48:22,720 --> 00:48:25,216
If we know the distance
between myself
724
00:48:25,240 --> 00:48:28,576
and the landing site, and if we know
the size of that ball,
725
00:48:28,600 --> 00:48:31,800
we can accurately calculate how long
it would take to get there.
726
00:48:35,800 --> 00:48:37,696
The result is surprising.
727
00:48:37,720 --> 00:48:40,176
Robert and his team calculated
728
00:48:40,200 --> 00:48:43,536
that these ejecta spherules
landed at Tanis
729
00:48:43,560 --> 00:48:47,920
between 13 minutes
and two hours after the impact.
730
00:48:50,520 --> 00:48:52,536
If a wave killed the fish,
731
00:48:52,560 --> 00:48:55,920
it must also have reached Tanis
within two hours.
732
00:49:00,000 --> 00:49:02,256
Data from recent tsunamis show
733
00:49:02,280 --> 00:49:05,616
even a powerful one would take much
longer than that
734
00:49:05,640 --> 00:49:09,416
to travel almost 2,000 miles
from the impact site
735
00:49:09,440 --> 00:49:10,880
to Tanis.
736
00:49:11,880 --> 00:49:14,496
So if it wasn't a tsunami,
737
00:49:14,520 --> 00:49:17,280
what could have caused
a surge of water at Tanis?
738
00:49:26,560 --> 00:49:30,560
Professor Stein Bondevik
is an expert in tsunamis.
739
00:49:36,040 --> 00:49:38,960
The fjords in Norway
are very special.
740
00:49:40,360 --> 00:49:44,336
We have tall mountains
surrounding bodies of water.
741
00:49:44,360 --> 00:49:47,616
So the water is usually very calm.
742
00:49:47,640 --> 00:49:52,336
In 2011, something very strange
happened.
743
00:49:52,360 --> 00:49:56,696
The water in the fjord
began to move violently.
744
00:49:56,720 --> 00:50:01,296
The height of the water increased
by one and a half metre,
745
00:50:01,320 --> 00:50:05,296
like a maelstrom
with the turbulent water.
746
00:50:05,320 --> 00:50:08,040
Someone said
that the fjord was boiling.
747
00:50:09,640 --> 00:50:11,456
News started to roll in -
748
00:50:11,480 --> 00:50:15,760
there'd been an earthquake
5,000 miles away in Japan.
749
00:50:18,680 --> 00:50:21,456
A journalist from
the local newspaper called me,
750
00:50:21,480 --> 00:50:24,376
and he said that
people were observing waves
751
00:50:24,400 --> 00:50:25,800
here, in the fjords.
752
00:50:27,920 --> 00:50:30,376
I got a video clip of the waves.
753
00:50:30,400 --> 00:50:33,816
I saw immediately that they looked
like a tsunami wave.
754
00:50:33,840 --> 00:50:35,656
So later in the afternoon,
755
00:50:35,680 --> 00:50:38,840
you can see that the fjord is
perfectly calm.
756
00:50:40,480 --> 00:50:41,696
But at the beach here,
757
00:50:41,720 --> 00:50:44,816
you could see that the water
is sloshing back and forth,
758
00:50:44,840 --> 00:50:47,800
and no-one had ever seen
anything like it.
759
00:50:49,160 --> 00:50:52,360
And some people
got very upset and afraid.
760
00:50:55,560 --> 00:51:00,776
A magnitude nine earthquake had
devastated the northeast of Japan,
761
00:51:00,800 --> 00:51:02,800
around Fukushima.
762
00:51:05,680 --> 00:51:09,520
But how did that affect a fjord
so far away?
763
00:51:12,160 --> 00:51:15,056
So no-one in Norway
could feel the earthquake,
764
00:51:15,080 --> 00:51:18,616
but I could see that
the times matched
765
00:51:18,640 --> 00:51:21,440
the arrival of the waves here,
in the fjord.
766
00:51:25,160 --> 00:51:28,416
Eventually,
Stein and his team realised
767
00:51:28,440 --> 00:51:33,176
that this might have something
to do with seismic waves -
768
00:51:33,200 --> 00:51:36,336
shock waves that pass quickly
through the Earth
769
00:51:36,360 --> 00:51:37,920
during an earthquake.
770
00:51:39,320 --> 00:51:42,776
So it took only 12 minutes
before the first signal
771
00:51:42,800 --> 00:51:45,456
of the earthquake in Japan
reached all the way here,
772
00:51:45,480 --> 00:51:46,840
to western Norway.
773
00:51:49,360 --> 00:51:51,136
So it was the seismic waves
774
00:51:51,160 --> 00:51:53,936
that caused the normally calm
water in the fjord
775
00:51:53,960 --> 00:51:56,920
to slosh turbulently
back and forth.
776
00:51:58,720 --> 00:52:03,680
Just thinking of that,
scientifically, it's fantastic.
777
00:52:09,800 --> 00:52:13,576
Could something similar
have happened in Tanis?
778
00:52:13,600 --> 00:52:16,920
A large weather front's
coming through the northwest…
779
00:52:18,360 --> 00:52:20,216
Trying to find out
780
00:52:20,240 --> 00:52:23,456
is geophysicist professor
Mark Richards,
781
00:52:23,480 --> 00:52:27,040
who's been studying the site at
Tanis for several years.
782
00:52:28,160 --> 00:52:30,496
He's working with Robert
to discover
783
00:52:30,520 --> 00:52:33,360
what could have caused
a surge of water here.
784
00:52:40,480 --> 00:52:43,760
A tsunami can't get here
in less than minimum 12 hours.
785
00:52:45,640 --> 00:52:49,456
But seismic waves travelling
from the Yucatan impact site
786
00:52:49,480 --> 00:52:52,360
to North Dakota
can arrive here fairly quickly.
787
00:52:54,640 --> 00:52:58,536
In the Late Cretaceous,
the Western Interior Seaway
788
00:52:58,560 --> 00:53:02,656
that divided North America could
have been connected to Tanis
789
00:53:02,680 --> 00:53:04,600
through a system of rivers.
790
00:53:09,840 --> 00:53:12,296
If you have
a very large body of water,
791
00:53:12,320 --> 00:53:15,296
like the Western Interior Seaway,
792
00:53:15,320 --> 00:53:17,576
and you can shake it back and forth,
793
00:53:17,600 --> 00:53:20,816
you can generate
a large water wave
794
00:53:20,840 --> 00:53:23,440
coming up this river at Tanis.
795
00:53:27,920 --> 00:53:31,616
So seismic waves from the impact
could have caused
796
00:53:31,640 --> 00:53:34,560
surges of water
in the Tanis river system.
797
00:53:35,640 --> 00:53:38,776
The seismic waves
get here quickly enough,
798
00:53:38,800 --> 00:53:41,136
coming up the Tanis river,
799
00:53:41,160 --> 00:53:43,536
inundating this area,
arriving at the same time
800
00:53:43,560 --> 00:53:46,240
these spherules are
still falling out of the air.
801
00:53:49,080 --> 00:53:50,656
The mystery of the wave
802
00:53:50,680 --> 00:53:54,976
and the thick layer of crumbly rock
has been solved.
803
00:53:55,000 --> 00:53:57,496
Seismic waves travelling
through the Earth
804
00:53:57,520 --> 00:54:01,360
could have caused powerful surges of
water at Tanis…
805
00:54:04,000 --> 00:54:06,456
…possibly carrying mud
and marine creatures,
806
00:54:06,480 --> 00:54:10,560
like ammonites, from the Western
Interior Seaway…
807
00:54:13,400 --> 00:54:17,896
…dumping them on the Tanis sandbank
and burying everything
808
00:54:17,920 --> 00:54:20,840
at the same time as spherules fell.
809
00:54:29,240 --> 00:54:30,456
Over millions of years,
810
00:54:30,480 --> 00:54:34,680
the mud would turn into
the layer of crumbly rock.
811
00:54:36,440 --> 00:54:38,496
And that's the beauty of Tanis.
812
00:54:38,520 --> 00:54:41,616
What you're seeing is a deposit
813
00:54:41,640 --> 00:54:45,976
that is literally recording
the last, say,
814
00:54:46,000 --> 00:54:49,840
45 minutes to an hour and a half
of the Cretaceous.
815
00:55:00,000 --> 00:55:03,176
If the extinction
of the dinosaurs was a crime,
816
00:55:03,200 --> 00:55:07,456
the detective solving it
would have plenty of evidence.
817
00:55:07,480 --> 00:55:09,376
They would see
that the asteroid was
818
00:55:09,400 --> 00:55:11,976
in the right place
at the right time.
819
00:55:12,000 --> 00:55:14,576
They would see
that no dinosaurs survived
820
00:55:14,600 --> 00:55:16,040
after the hit.
821
00:55:17,040 --> 00:55:19,336
They would have a piece
of the murder weapon -
822
00:55:19,360 --> 00:55:21,416
a fragment of the asteroid.
823
00:55:21,440 --> 00:55:25,376
But they would be missing
one very important thing -
824
00:55:25,400 --> 00:55:26,960
a body.
825
00:55:31,520 --> 00:55:35,216
No-one has ever found
the fossil of a dinosaur
826
00:55:35,240 --> 00:55:39,576
that was killed by the effects
of the asteroid impact.
827
00:55:39,600 --> 00:55:43,176
But Robert did find
part of a triceratops
828
00:55:43,200 --> 00:55:45,496
in the crumbly layer at Tanis.
829
00:55:45,520 --> 00:55:47,696
So could that be the remains
830
00:55:47,720 --> 00:55:50,576
of a dinosaur
that died on that day?
831
00:55:50,600 --> 00:55:52,096
I'm still dubious about the horn.
832
00:55:52,120 --> 00:55:54,096
I kind of want to keep
the horn in the jacket.
833
00:55:54,120 --> 00:55:55,336
I think if you took it off,
834
00:55:55,360 --> 00:55:56,976
at least take this section off,
835
00:55:57,000 --> 00:55:58,616
to see what's going on under here.
836
00:55:58,640 --> 00:55:59,776
Yeah?
837
00:55:59,800 --> 00:56:04,616
To find out, the team needs to
establish cause of death,
838
00:56:04,640 --> 00:56:07,976
which can be difficult when you only
have a piece of skin
839
00:56:08,000 --> 00:56:10,120
and a horn to go on.
840
00:56:12,240 --> 00:56:16,336
This is the horn
after they've cleaned it up.
841
00:56:16,360 --> 00:56:20,816
The team is particularly
interested in these lines here.
842
00:56:20,840 --> 00:56:23,416
And they found that the fractures go
843
00:56:23,440 --> 00:56:26,016
right through the horn.
844
00:56:26,040 --> 00:56:29,296
So rather than dying
as a result of the impact,
845
00:56:29,320 --> 00:56:32,680
they wondered whether
it had been killed in a fight.
846
00:56:38,400 --> 00:56:40,776
But when they looked at
the fractures in more detail,
847
00:56:40,800 --> 00:56:43,680
they found signs
of new bone growth here.
848
00:56:44,720 --> 00:56:48,096
An indication that
the bone had started to heal.
849
00:56:48,120 --> 00:56:50,656
So it looked as though
the triceratops survived
850
00:56:50,680 --> 00:56:53,120
the event that broke its horn.
851
00:56:57,760 --> 00:57:00,496
Could this triceratops
have survived
852
00:57:00,520 --> 00:57:03,216
until the day of the impact?
853
00:57:03,240 --> 00:57:06,856
The team found evidence,
including sagging in the skin,
854
00:57:06,880 --> 00:57:10,616
which suggested that
there was decay underneath.
855
00:57:10,640 --> 00:57:13,016
That means its body had started
to rot
856
00:57:13,040 --> 00:57:16,936
before it was entombed
and preserved by the surge.
857
00:57:16,960 --> 00:57:21,976
So it seems that this dinosaur
didn't die as a result
858
00:57:22,000 --> 00:57:23,960
of the asteroid impact.
859
00:57:25,640 --> 00:57:28,736
Perhaps, in the months
before the impact,
860
00:57:28,760 --> 00:57:30,816
the broken horn put the triceratops
861
00:57:30,840 --> 00:57:33,280
at a disadvantage over its rivals.
862
00:57:49,000 --> 00:57:51,720
And that might have led
to starvation.
863
00:58:13,840 --> 00:58:17,096
Robert has still not found
direct evidence
864
00:58:17,120 --> 00:58:20,080
of a dinosaur that was killed
by the asteroid.
865
00:58:21,280 --> 00:58:23,336
We've got all these bones
in the ground right now.
866
00:58:23,360 --> 00:58:26,136
But the one thing
that we would just dream
867
00:58:26,160 --> 00:58:28,096
of finding is that one dinosaur
868
00:58:28,120 --> 00:58:30,760
that died on the day of the impact.
869
00:58:34,640 --> 00:58:37,800
And the weather
isn't helping his search.
870
00:58:55,680 --> 00:58:57,856
That therapod print is toasted.
871
00:58:57,880 --> 00:59:00,016
Yeah, it was in a low corner.
872
00:59:00,040 --> 00:59:03,056
Look, it's full mud.
It's full of mud and water.
873
00:59:03,080 --> 00:59:05,216
The problem is it's wet, look.
874
00:59:05,240 --> 00:59:07,960
See… If we're not careful,
we're going to lose the print.
875
00:59:09,280 --> 00:59:11,400
And that's the biggest
theropod print we've got.
876
00:59:12,440 --> 00:59:15,040
I see some areas that could use
glue right now, too.
877
00:59:17,560 --> 00:59:20,856
The team is racing
to excavate the footprints,
878
00:59:20,880 --> 00:59:23,296
along with dozens of fish fossils
879
00:59:23,320 --> 00:59:28,040
tangled together in a logjam,
before storms wash them away.
880
00:59:29,400 --> 00:59:30,976
We're up against the clock here.
881
00:59:31,000 --> 00:59:32,816
This stuff that could be
exposed right now
882
00:59:32,840 --> 00:59:34,680
is going to get ruined by the rain.
883
00:59:37,240 --> 00:59:39,816
But then,
Robert comes across something
884
00:59:39,840 --> 00:59:41,496
that looks very unusual.
885
00:59:41,520 --> 00:59:43,280
That's going there.
886
00:59:44,880 --> 00:59:46,536
What is going on right there?
887
00:59:46,560 --> 00:59:48,896
Are we sure
this isn't crocodilian?
888
00:59:48,920 --> 00:59:50,896
That's not crocodilian. No.
889
00:59:50,920 --> 00:59:53,496
Right, let me try
this piece right here.
890
00:59:53,520 --> 00:59:56,136
I'll go in from the top
and then twist up,
891
00:59:56,160 --> 00:59:57,736
and it separates right on that line.
892
00:59:57,760 --> 01:00:00,256
Oh, that's skin right there.
893
01:00:00,280 --> 01:00:02,736
That's actually scaly skin.
Oh, my God.
894
01:00:02,760 --> 01:00:04,576
No, no, no, no, no.
Look, look, look.
895
01:00:04,600 --> 01:00:06,536
Look at that pattern
right there.
896
01:00:06,560 --> 01:00:09,296
Have you ever seen elongated
scales like that before, Dave?
897
01:00:09,320 --> 01:00:11,536
That's insane.
Scuttelates - in birds.
898
01:00:11,560 --> 01:00:13,296
Just careful.
899
01:00:13,320 --> 01:00:15,656
Oh, my God.
It's changing again.
900
01:00:15,680 --> 01:00:17,200
It's changing again.
Oh, my God.
901
01:00:18,480 --> 01:00:21,976
We're seeing it for the first time
in 66 million years.
902
01:00:22,000 --> 01:00:23,960
I think we've got ourselves
a dinosaur.
903
01:00:28,560 --> 01:00:30,216
A dinosaur fossil!
904
01:00:30,240 --> 01:00:33,336
And, unlike the triceratops,
905
01:00:33,360 --> 01:00:37,576
this is located in the logjam,
the mass death layer,
906
01:00:37,600 --> 01:00:41,920
surrounded by the fish
with spherules in their gills.
907
01:00:44,800 --> 01:00:47,656
This is the most incredible thing
that we could possibly imagine here.
908
01:00:47,680 --> 01:00:49,296
The best-case scenario.
909
01:00:49,320 --> 01:00:52,376
We're excavating
this mass death layer of fish
910
01:00:52,400 --> 01:00:55,256
from the surge
sent up by the impact,
911
01:00:55,280 --> 01:00:57,336
and we've got dinosaur remains.
912
01:00:57,360 --> 01:01:00,616
The one thing that we would always
want to find at this site,
913
01:01:00,640 --> 01:01:02,936
and here we've got it.
914
01:01:02,960 --> 01:01:06,656
This is unreal. I-I-I cannot
process this in my brain.
915
01:01:06,680 --> 01:01:09,296
No, I am absolutely blown away
by this.
916
01:01:09,320 --> 01:01:11,736
Just my heart is literally
pumping out of my chest
917
01:01:11,760 --> 01:01:13,136
wondering what is behind there,
918
01:01:13,160 --> 01:01:15,336
just a couple of centimetres
back in the outcrop.
919
01:01:15,360 --> 01:01:17,000
What is waiting for us back there?
920
01:01:18,720 --> 01:01:20,536
Get it out…
921
01:01:20,560 --> 01:01:22,136
This is…
922
01:01:22,160 --> 01:01:23,456
The team keeps digging.
923
01:01:23,480 --> 01:01:25,416
The scales get big again
over on this side.
924
01:01:25,440 --> 01:01:26,976
So this could be a ribcage,
925
01:01:27,000 --> 01:01:29,136
it could be laying against ribs
that are curved.
926
01:01:29,160 --> 01:01:30,696
There's something here.
927
01:01:30,720 --> 01:01:32,176
That's hard. A bit more bone.
928
01:01:32,200 --> 01:01:34,136
That's bone right next
to the skin.
929
01:01:34,160 --> 01:01:36,176
Yeah, that's an articular
surface right there,
930
01:01:36,200 --> 01:01:38,640
so this is either a hip
or a shoulder element.
931
01:01:42,640 --> 01:01:45,800
After hours
of painstaking work…
932
01:01:49,000 --> 01:01:51,376
And we can go
from the thigh of the animal.
933
01:01:51,400 --> 01:01:53,016
There's the knee.
934
01:01:53,040 --> 01:01:55,736
And then you've got
the little calf muscles
935
01:01:55,760 --> 01:01:57,616
of the dinosaur,
they're bulging out,
936
01:01:57,640 --> 01:02:00,576
and you go down
to the anklebones,
937
01:02:00,600 --> 01:02:03,376
and these are the toes
of the feet.
938
01:02:03,400 --> 01:02:05,416
We have got nails
at the tips of the toes.
939
01:02:05,440 --> 01:02:07,256
It's a beautifully preserved leg,
940
01:02:07,280 --> 01:02:09,120
all articulated, covered with skin.
941
01:02:10,240 --> 01:02:14,056
The complete leg of a dinosaur.
942
01:02:14,080 --> 01:02:16,096
In my wildest dreams,
943
01:02:16,120 --> 01:02:18,336
I never expected to find
a dinosaur leg in this deposit.
944
01:02:18,360 --> 01:02:21,696
Yeah. I mean, and then
it's got skin and tissue.
945
01:02:21,720 --> 01:02:24,176
It does look
just like a drumstick.
946
01:02:24,200 --> 01:02:26,056
It looks like
a Thanksgiving turkey,
947
01:02:26,080 --> 01:02:27,816
just laid out in the ground.
948
01:02:27,840 --> 01:02:31,696
And this weird scale pattern
on the thigh of the animal,
949
01:02:31,720 --> 01:02:34,456
which we've never seen
in a dinosaur before.
950
01:02:34,480 --> 01:02:37,216
Well, thescelosaurs don't have
any form of defence,
951
01:02:37,240 --> 01:02:39,456
so they have to have camouflage
or something.
952
01:02:39,480 --> 01:02:40,896
That's a good point.
953
01:02:40,920 --> 01:02:44,456
So this could have been some
sort of a camouflage marking. Yeah.
954
01:02:44,480 --> 01:02:48,216
Robert thinks he has found
the body in question -
955
01:02:48,240 --> 01:02:52,456
a dinosaur that might itself
have witnessed
956
01:02:52,480 --> 01:02:54,320
the cataclysmic impact.
957
01:02:57,520 --> 01:02:59,776
Dinosaur fossils are not known
958
01:02:59,800 --> 01:03:02,656
from the last years
of the Cretaceous.
959
01:03:02,680 --> 01:03:05,256
And it was unclear whether
they were already extinct
960
01:03:05,280 --> 01:03:07,136
or in decline
or what was going on.
961
01:03:07,160 --> 01:03:09,000
So they were just sort of absent.
962
01:03:12,560 --> 01:03:13,976
And this answers that question.
963
01:03:14,000 --> 01:03:16,576
Were dinosaurs still there then?
964
01:03:16,600 --> 01:03:20,720
Well, yes - this one likely
died in that surge.
965
01:03:24,560 --> 01:03:29,160
For such big claims,
Robert needs verification.
966
01:03:31,480 --> 01:03:33,736
He's brought the dinosaur leg
to London
967
01:03:33,760 --> 01:03:36,416
to get a second opinion…
968
01:03:36,440 --> 01:03:38,976
And then here are the pads
of the toes.
969
01:03:39,000 --> 01:03:41,616
We see all those
beautiful scales lined up.
970
01:03:41,640 --> 01:03:43,936
…from Professor Paul Barrett,
971
01:03:43,960 --> 01:03:47,176
an expert
in ornithischian dinosaurs
972
01:03:47,200 --> 01:03:50,056
from the Natural History Museum.
973
01:03:50,080 --> 01:03:52,336
So what do you think
this might be?
974
01:03:52,360 --> 01:03:55,216
When we look at the leg,
it has claws,
975
01:03:55,240 --> 01:03:59,816
like the claws we see in small,
agile, bipedal, running dinosaurs
976
01:03:59,840 --> 01:04:02,216
that are plant-eaters.
977
01:04:02,240 --> 01:04:04,216
We can rule out things
like triceratops,
978
01:04:04,240 --> 01:04:06,616
partly just because
it's not big and stocky.
979
01:04:06,640 --> 01:04:09,816
And the proportions of those legs
are also different
980
01:04:09,840 --> 01:04:12,096
from some of
the other plant-eaters we see,
981
01:04:12,120 --> 01:04:13,976
in that they have
this rather long ankle
982
01:04:14,000 --> 01:04:17,336
and shin, compared with its
thighbone.
983
01:04:17,360 --> 01:04:19,376
So as we narrow
those possibilities down,
984
01:04:19,400 --> 01:04:20,856
what we're left with, probably,
985
01:04:20,880 --> 01:04:22,720
is an animal called a thescelosaur.
986
01:04:31,680 --> 01:04:34,376
Thescelosaurs lived next to rivers
987
01:04:34,400 --> 01:04:37,440
where there was plenty
of rich vegetation to feed on.
988
01:04:39,920 --> 01:04:42,176
They had leaf-shaped teeth,
989
01:04:42,200 --> 01:04:44,216
common amongst herbivores,
990
01:04:44,240 --> 01:04:46,296
and claws
on their short front limbs -
991
01:04:46,320 --> 01:04:48,480
excellent for digging.
992
01:05:05,920 --> 01:05:09,120
But how did
Robert's thescelosaur die?
993
01:05:10,720 --> 01:05:13,616
Could it have been killed
by another dinosaur?
994
01:05:13,640 --> 01:05:15,336
It's a possibility.
995
01:05:15,360 --> 01:05:17,416
This is a relatively agile animal.
996
01:05:17,440 --> 01:05:19,576
And that turn of speed
would've been
997
01:05:19,600 --> 01:05:23,600
its primary defence against the
large predators living alongside it.
998
01:05:29,000 --> 01:05:32,856
So, to escape a hungry T-rex,
999
01:05:32,880 --> 01:05:35,280
a thescelosaur's first line
of defence…
1000
01:05:36,600 --> 01:05:38,120
…would've been to run.
1001
01:05:40,800 --> 01:05:45,040
But it may have had
another defensive trick.
1002
01:05:53,520 --> 01:05:55,056
Living next to rivers,
1003
01:05:55,080 --> 01:05:58,880
it's possible thescelosaurs
were able to swim.
1004
01:06:12,280 --> 01:06:14,696
It doesn't seem to me
like there is any evidence
1005
01:06:14,720 --> 01:06:16,376
that this animal was predated -
1006
01:06:16,400 --> 01:06:19,016
none of the obvious tooth marks
1007
01:06:19,040 --> 01:06:21,176
or leftover bits
of carnivore teeth
1008
01:06:21,200 --> 01:06:23,256
to suggest it's been eaten.
1009
01:06:23,280 --> 01:06:25,816
So how do you think it died?
1010
01:06:25,840 --> 01:06:28,776
It didn't have any particularly
nasty diseases when it died,
1011
01:06:28,800 --> 01:06:31,496
as we can see
that the bones look OK.
1012
01:06:31,520 --> 01:06:33,456
So this is an animal
that was probably living
1013
01:06:33,480 --> 01:06:36,696
and healthy at the time
that this happened to it.
1014
01:06:36,720 --> 01:06:41,816
Could this be a victim
of the meteor strike?
1015
01:06:41,840 --> 01:06:43,216
I think it's entirely possible.
1016
01:06:43,240 --> 01:06:45,416
This is actually a shoulder bone,
1017
01:06:45,440 --> 01:06:47,376
and this bone in a living animal
1018
01:06:47,400 --> 01:06:49,416
would actually be way over here.
1019
01:06:49,440 --> 01:06:51,216
And similarly, this little bone here
1020
01:06:51,240 --> 01:06:54,016
would've been from about
maybe a third of the way
1021
01:06:54,040 --> 01:06:55,976
along the tail, maybe halfway down.
1022
01:06:56,000 --> 01:07:00,536
So somehow these two bones
have been telescoped together.
1023
01:07:00,560 --> 01:07:02,976
So maybe this animal's
been tumbled around.
1024
01:07:03,000 --> 01:07:05,616
We've ruled out
a lot of other possible
1025
01:07:05,640 --> 01:07:07,576
causes of death for this animal.
1026
01:07:07,600 --> 01:07:10,536
So it could well be
that this is an animal
1027
01:07:10,560 --> 01:07:12,296
that was there, being tumbled around
1028
01:07:12,320 --> 01:07:13,976
in its death throes, in that river,
1029
01:07:14,000 --> 01:07:15,760
as a result of the asteroid impact.
1030
01:07:17,120 --> 01:07:19,656
Well, it is exactly analogous
1031
01:07:19,680 --> 01:07:22,816
to those human bodies
found in Pompeii.
1032
01:07:22,840 --> 01:07:26,056
It's very similar in terms of
you get that quick entombment.
1033
01:07:26,080 --> 01:07:28,096
Yes. And it's almost as evocative.
1034
01:07:28,120 --> 01:07:30,376
That's absolutely true.
1035
01:07:30,400 --> 01:07:32,656
You've got literally
the blink of an eye
1036
01:07:32,680 --> 01:07:34,536
at the end of the Cretaceous,
1037
01:07:34,560 --> 01:07:36,696
snapped up into history,
and there it is,
1038
01:07:36,720 --> 01:07:40,160
ready to be dug up. Wow.
1039
01:07:51,560 --> 01:07:53,816
After years of investigation,
1040
01:07:53,840 --> 01:07:56,096
Robert has found out a great deal
1041
01:07:56,120 --> 01:07:58,216
about the creatures
which lived at Tanis,
1042
01:07:58,240 --> 01:08:02,816
and he knows that many of them were
alive on that fateful day
1043
01:08:02,840 --> 01:08:05,920
when the asteroid
devastated our planet.
1044
01:08:07,040 --> 01:08:09,240
But how exactly did they die?
1045
01:08:10,240 --> 01:08:14,056
Robert's finds now allow us
to tell the story of that day
1046
01:08:14,080 --> 01:08:16,560
and finally answer that question.
1047
01:08:20,880 --> 01:08:23,816
One of the most important days
in Earth's history
1048
01:08:23,840 --> 01:08:27,760
probably started much like any
other late spring morning.
1049
01:08:32,880 --> 01:08:37,736
We know the season because Robert
found fossils of young fish that
1050
01:08:37,760 --> 01:08:40,416
died at the size they reach
at that time of year.
1051
01:08:40,440 --> 01:08:43,056
This agrees
with evidence already found
1052
01:08:43,080 --> 01:08:45,120
by other scientists.
1053
01:08:47,560 --> 01:08:51,176
Perhaps this day, that would end
with so much death,
1054
01:08:51,200 --> 01:08:53,800
began with something different.
1055
01:08:55,600 --> 01:08:57,200
A new life.
1056
01:09:20,680 --> 01:09:23,976
No-one can be certain
of the exact timings of the day
1057
01:09:24,000 --> 01:09:27,096
when the asteroid collided
with our planet.
1058
01:09:27,120 --> 01:09:31,456
But it's estimated that within
just 40 minutes of the impact,
1059
01:09:31,480 --> 01:09:34,016
the consequences
for the creatures of Tanis
1060
01:09:34,040 --> 01:09:35,600
would have been profound.
1061
01:09:39,720 --> 01:09:41,096
Based on Robert's finds
1062
01:09:41,120 --> 01:09:43,896
and the latest evidence
from other scientists,
1063
01:09:43,920 --> 01:09:47,400
this is how the catastrophe
might have unfolded.
1064
01:09:50,080 --> 01:09:53,576
The asteroid is around
seven miles across,
1065
01:09:53,600 --> 01:09:55,480
bigger than Mount Everest…
1066
01:09:57,040 --> 01:10:01,520
…and travelling at close
to 45,000mph.
1067
01:10:05,320 --> 01:10:07,496
The impact causes an explosion
1068
01:10:07,520 --> 01:10:11,680
bigger than a billion
Hiroshima atomic bombs.
1069
01:10:18,960 --> 01:10:21,840
At Tanis,
almost 2,000 miles away…
1070
01:10:23,440 --> 01:10:25,560
…it's completely silent.
1071
01:10:29,560 --> 01:10:31,480
But at the impact site…
1072
01:10:33,800 --> 01:10:35,720
…the asteroid vaporises.
1073
01:10:37,600 --> 01:10:40,096
More than three trillion
tonnes of rock
1074
01:10:40,120 --> 01:10:42,016
are ejected into space
1075
01:10:42,040 --> 01:10:44,680
in a blast
of super-heated violence.
1076
01:10:49,480 --> 01:10:52,400
Winds higher than 600mph.
1077
01:10:53,880 --> 01:10:58,560
A colossal earthquake, followed
by a ring of massive tsunamis.
1078
01:11:09,040 --> 01:11:11,016
All the while,
the creatures at Tanis
1079
01:11:11,040 --> 01:11:12,896
go about their business…
1080
01:11:16,920 --> 01:11:19,360
…just like any other day.
1081
01:11:37,400 --> 01:11:40,096
The evidence suggests
that baby pterosaurs
1082
01:11:40,120 --> 01:11:43,600
emerge from the egg
ready to fend for themselves.
1083
01:11:46,240 --> 01:11:48,120
And that includes…
1084
01:11:50,720 --> 01:11:52,120
…flying?
1085
01:11:53,600 --> 01:11:55,200
Well, almost.
1086
01:12:03,840 --> 01:12:08,056
Elsewhere, as the devastation
spreads out across North America
1087
01:12:08,080 --> 01:12:09,400
towards Tanis…
1088
01:12:11,040 --> 01:12:14,136
…dinosaurs and creatures
of all shapes and sizes
1089
01:12:14,160 --> 01:12:16,600
are obliterated by the blast.
1090
01:12:28,040 --> 01:12:31,536
At Tanis, for a few more
precious minutes,
1091
01:12:31,560 --> 01:12:33,280
life carries on as usual.
1092
01:12:35,360 --> 01:12:37,560
But the clock is ticking.
1093
01:12:51,080 --> 01:12:54,816
The blast from the impact
never reaches Tanis,
1094
01:12:54,840 --> 01:12:57,360
but seismic shock waves do.
1095
01:13:10,440 --> 01:13:12,416
They are far more powerful
1096
01:13:12,440 --> 01:13:14,880
than any earthquake
ever recorded.
1097
01:13:23,480 --> 01:13:26,920
The thescelosaur might head
for a place of safety…
1098
01:13:31,680 --> 01:13:34,016
…but seismic waves
are now slowly shaking
1099
01:13:34,040 --> 01:13:38,440
the whole region, causing water
to slosh and churn.
1100
01:13:43,760 --> 01:13:46,816
At Tanis,
strange currents in the river
1101
01:13:46,840 --> 01:13:49,480
give a hint
of what is still to come.
1102
01:13:58,480 --> 01:14:01,360
Next, it begins to rain.
1103
01:14:03,480 --> 01:14:06,720
Ejecta spherules
are falling back to Earth.
1104
01:14:14,600 --> 01:14:17,520
As the spherules
begin their fall…
1105
01:14:18,640 --> 01:14:21,960
…friction heats them
until they're red hot.
1106
01:14:28,400 --> 01:14:31,800
Then the heat transfers
to the air.
1107
01:14:33,280 --> 01:14:35,560
Temperatures rise with every second.
1108
01:14:44,000 --> 01:14:47,296
As the heat builds,
the creatures of Tanis
1109
01:14:47,320 --> 01:14:48,960
are fighting for their lives.
1110
01:14:54,080 --> 01:14:56,536
And then, as seismic waves
1111
01:14:56,560 --> 01:14:59,360
continue to slowly rock
the whole region…
1112
01:15:02,880 --> 01:15:06,176
…a violent surge wave
ten metres high
1113
01:15:06,200 --> 01:15:08,520
rushes up the Tanis river.
1114
01:15:27,440 --> 01:15:29,896
Surviving the turbulence
of the surge
1115
01:15:29,920 --> 01:15:33,080
is a challenge
even for the best swimmers.
1116
01:15:45,000 --> 01:15:48,816
Then, the powerful rocking
of the river system
1117
01:15:48,840 --> 01:15:52,480
slowly begins to draw the water
back the way it came.
1118
01:16:02,120 --> 01:16:03,856
Swimming may have saved
1119
01:16:03,880 --> 01:16:06,536
the thescelosaur in the past,
1120
01:16:06,560 --> 01:16:08,360
but not this time.
1121
01:16:13,960 --> 01:16:16,536
A large, robust animal
like a T-rex
1122
01:16:16,560 --> 01:16:18,640
might have survived the surge.
1123
01:16:24,120 --> 01:16:26,480
As might a hard-shelled reptile.
1124
01:16:28,160 --> 01:16:30,976
But there is much more to come.
1125
01:16:31,000 --> 01:16:36,096
As billions of tonnes of superheated
spherules continue to fall,
1126
01:16:36,120 --> 01:16:38,440
the atmosphere gets even hotter…
1127
01:16:40,880 --> 01:16:45,000
…igniting dead leaves
and sparking wildfires.
1128
01:16:51,320 --> 01:16:52,896
Earthquakes,
1129
01:16:52,920 --> 01:16:54,880
fire…
1130
01:16:57,000 --> 01:16:58,480
…devastation.
1131
01:17:01,000 --> 01:17:03,016
Little would survive for long,
1132
01:17:03,040 --> 01:17:04,880
on land…
1133
01:17:09,520 --> 01:17:11,320
…or in the air.
1134
01:17:31,640 --> 01:17:35,520
As the air reaches the temperature
of an industrial oven…
1135
01:17:38,480 --> 01:17:40,536
…those that live
deep underground
1136
01:17:40,560 --> 01:17:42,120
may have a better chance.
1137
01:17:50,080 --> 01:17:53,600
As the slow sloshing of
the river system continues…
1138
01:17:56,520 --> 01:17:58,840
…another powerful surge hits.
1139
01:18:19,720 --> 01:18:22,320
There is no escaping
the destruction.
1140
01:18:25,480 --> 01:18:28,496
For many of the creatures
of Tanis,
1141
01:18:28,520 --> 01:18:30,920
their stories end underwater.
1142
01:18:46,520 --> 01:18:50,760
In less than two hours,
the world has changed forever.
1143
01:18:57,440 --> 01:19:00,176
The mud the surge waves leave behind
1144
01:19:00,200 --> 01:19:04,176
will gradually turn into the thick
layer of crumbly rock
1145
01:19:04,200 --> 01:19:07,120
entombing the creatures
which died here…
1146
01:19:10,000 --> 01:19:13,096
…until 66 million years later,
1147
01:19:13,120 --> 01:19:15,440
when they're finally unearthed.
1148
01:19:24,840 --> 01:19:29,136
Robert's finds have helped us
understand in remarkable detail
1149
01:19:29,160 --> 01:19:30,816
what happened at Tanis
1150
01:19:30,840 --> 01:19:34,336
in the minutes
after the asteroid impact.
1151
01:19:34,360 --> 01:19:36,520
But what about
the rest of the world?
1152
01:19:39,640 --> 01:19:42,456
The impact triggered catastrophic
events
1153
01:19:42,480 --> 01:19:45,360
such as earthquakes all over
the planet.
1154
01:19:47,000 --> 01:19:49,480
And as spherules
continued to fall…
1155
01:19:52,520 --> 01:19:55,800
…wildfires may have sprung up
around the globe.
1156
01:19:58,560 --> 01:20:01,816
As that horrific day
drew to a close,
1157
01:20:01,840 --> 01:20:05,640
many of the world's dinosaurs
were already dead.
1158
01:20:11,200 --> 01:20:15,656
Research shows that the angle
at which the asteroid hit
1159
01:20:15,680 --> 01:20:18,656
and the sulphur-rich rocks
at the impact site
1160
01:20:18,680 --> 01:20:20,936
amplified the devastation.
1161
01:20:20,960 --> 01:20:22,896
Billions of tonnes of sulphur
1162
01:20:22,920 --> 01:20:25,176
were ejected into the atmosphere,
1163
01:20:25,200 --> 01:20:27,080
blocking the sunlight.
1164
01:20:29,200 --> 01:20:34,040
Without light, most plants died,
and food became scarce.
1165
01:20:35,840 --> 01:20:38,496
As the weeks and months passed,
1166
01:20:38,520 --> 01:20:41,920
any dinosaur left alive
would've died of hunger.
1167
01:20:44,760 --> 01:20:47,456
In the oceans, it was the same.
1168
01:20:47,480 --> 01:20:50,776
Nearly all of the world's
plankton disappeared,
1169
01:20:50,800 --> 01:20:54,840
leading to the starvation
of most marine creatures.
1170
01:20:56,440 --> 01:20:59,936
It's thought that the nuclear
winter that followed
1171
01:20:59,960 --> 01:21:02,576
caused a global temperature drop
1172
01:21:02,600 --> 01:21:05,536
of at least
25 degrees centigrade.
1173
01:21:05,560 --> 01:21:09,536
The fossil record tells us that this
huge change in climate
1174
01:21:09,560 --> 01:21:13,416
marked the disappearance of three
quarters of all species,
1175
01:21:13,440 --> 01:21:15,280
including the dinosaurs.
1176
01:21:17,760 --> 01:21:22,296
The planet was in semi-darkness
for around a decade,
1177
01:21:22,320 --> 01:21:25,520
as dust and soot
slowly fell to Earth.
1178
01:21:27,320 --> 01:21:29,680
But then came something wonderful.
1179
01:21:31,560 --> 01:21:33,280
A new beginning.
1180
01:21:37,680 --> 01:21:40,376
Once the dust cleared
from the atmosphere
1181
01:21:40,400 --> 01:21:42,080
and the sunlight returned…
1182
01:21:43,600 --> 01:21:47,216
…plant life was gradually restored,
1183
01:21:47,240 --> 01:21:49,176
led by ferns,
1184
01:21:49,200 --> 01:21:53,376
the spores of which had lain
dormant deep underground,
1185
01:21:53,400 --> 01:21:57,400
and the world began
to turn green once more.
1186
01:21:59,600 --> 01:22:01,720
But what about the animals?
1187
01:22:04,400 --> 01:22:07,736
Back at Tanis,
Robert has unearthed something
1188
01:22:07,760 --> 01:22:10,536
that could have helped save
some of the creatures
1189
01:22:10,560 --> 01:22:13,136
from the devastating fires.
1190
01:22:13,160 --> 01:22:14,776
We saw a little thing
poking out,
1191
01:22:14,800 --> 01:22:16,776
so we kind of followed it back.
1192
01:22:16,800 --> 01:22:18,816
And I'm so glad that we did,
1193
01:22:18,840 --> 01:22:21,136
because what we have here
is a fossil burrow
1194
01:22:21,160 --> 01:22:23,920
from an animal 66 million years ago.
1195
01:22:25,520 --> 01:22:27,896
The only animals that
would've been around back then
1196
01:22:27,920 --> 01:22:30,176
that would likely build
a burrow like this
1197
01:22:30,200 --> 01:22:33,096
would be the small mammals,
roughly ferret-sized,
1198
01:22:33,120 --> 01:22:35,656
and also some reptiles.
1199
01:22:35,680 --> 01:22:39,896
If it is from a mammal,
this is sort of a window
1200
01:22:39,920 --> 01:22:42,800
into the lifestyle of some of
our oldest ancestors out here.
1201
01:22:43,840 --> 01:22:45,856
This guy would've burrowed
sideways,
1202
01:22:45,880 --> 01:22:47,320
right into the river bank.
1203
01:22:48,640 --> 01:22:50,696
We actually have
some scratch marks on there
1204
01:22:50,720 --> 01:22:52,896
from the interior
when they were digging it,
1205
01:22:52,920 --> 01:22:55,776
going back,
and he would've lived back here
1206
01:22:55,800 --> 01:22:57,576
and sought shelter
from the dinosaurs
1207
01:22:57,600 --> 01:22:59,880
cos they just did not
want to get eaten.
1208
01:23:06,240 --> 01:23:08,496
Burrows are part of the reason
1209
01:23:08,520 --> 01:23:11,560
that mammals survived
the great extinction.
1210
01:23:13,240 --> 01:23:15,096
During the nuclear winter,
1211
01:23:15,120 --> 01:23:17,296
a burrow would've provided warmth,
1212
01:23:17,320 --> 01:23:20,520
protection,
and a place to store food.
1213
01:23:27,760 --> 01:23:31,096
Mammals that survived
were resourceful omnivores,
1214
01:23:31,120 --> 01:23:34,920
and insects would've been
a plentiful source of food.
1215
01:23:40,600 --> 01:23:44,360
And they had another advantage -
their size.
1216
01:23:46,680 --> 01:23:50,456
If conditions are right,
many animal species get larger
1217
01:23:50,480 --> 01:23:53,416
as they evolve
over millions of years.
1218
01:23:53,440 --> 01:23:56,896
Take T-rex as an example.
1219
01:23:56,920 --> 01:24:00,176
This is a cast of the lower jaw
1220
01:24:00,200 --> 01:24:02,816
of a predecessor, called
gorgosaurus,
1221
01:24:02,840 --> 01:24:05,576
which lived
72 million years ago.
1222
01:24:05,600 --> 01:24:11,496
Whereas this is the cast
of the lower jaw of a T-rex,
1223
01:24:11,520 --> 01:24:14,096
which lived
five million years later.
1224
01:24:14,120 --> 01:24:18,016
Look at the difference in size.
1225
01:24:18,040 --> 01:24:19,416
But the bigger the creature,
1226
01:24:19,440 --> 01:24:21,976
the more energy they need
to stay alive.
1227
01:24:22,000 --> 01:24:25,816
So when catastrophe strikes
and food is scarce,
1228
01:24:25,840 --> 01:24:28,176
the largest tend to die out,
1229
01:24:28,200 --> 01:24:31,160
whilst the smallest
often survive.
1230
01:24:34,280 --> 01:24:36,176
That's one of the reasons
1231
01:24:36,200 --> 01:24:38,616
why many of the smaller mammals
1232
01:24:38,640 --> 01:24:41,416
lived through the great darkness.
1233
01:24:41,440 --> 01:24:43,480
And they weren't alone.
1234
01:24:46,000 --> 01:24:49,176
Robert's fossil turtle
may have been unlucky,
1235
01:24:49,200 --> 01:24:50,920
but many others survived.
1236
01:24:54,640 --> 01:24:57,216
As did crocodiles,
1237
01:24:57,240 --> 01:24:59,016
snakes,
1238
01:24:59,040 --> 01:25:01,936
and many fish species.
1239
01:25:01,960 --> 01:25:04,696
And as for the dinosaurs,
1240
01:25:04,720 --> 01:25:07,176
did the impact
really kill them all?
1241
01:25:07,200 --> 01:25:10,856
Well, this beautiful
fossilised feather
1242
01:25:10,880 --> 01:25:12,896
isn't from a bird,
1243
01:25:12,920 --> 01:25:15,056
but from a predatory dinosaur.
1244
01:25:15,080 --> 01:25:16,776
So we have to be careful
1245
01:25:16,800 --> 01:25:20,016
when we say
that dinosaurs are extinct,
1246
01:25:20,040 --> 01:25:24,096
because what we call birds
originally evolved
1247
01:25:24,120 --> 01:25:27,136
from the smallest
feathered dinosaurs.
1248
01:25:27,160 --> 01:25:29,376
So to be correct, we should say
1249
01:25:29,400 --> 01:25:33,360
all non-avian dinosaurs
are extinct.
1250
01:25:36,160 --> 01:25:38,296
Robert's finds have given us
1251
01:25:38,320 --> 01:25:40,640
a better idea
than ever before…
1252
01:25:42,240 --> 01:25:46,040
…about what happened on the day
that led to the extinction…
1253
01:25:48,080 --> 01:25:51,600
…of the largest beasts
ever to walk the Earth.
1254
01:25:55,000 --> 01:25:57,216
Dinosaurs were perhaps
1255
01:25:57,240 --> 01:26:00,656
some of nature's
most extraordinary creatures,
1256
01:26:00,680 --> 01:26:04,736
dominating the planet
for over 150 million years
1257
01:26:04,760 --> 01:26:06,720
before they became extinct.
1258
01:26:09,440 --> 01:26:12,256
But extinction
comes in different forms,
1259
01:26:12,280 --> 01:26:14,536
and many of the amazing creatures
1260
01:26:14,560 --> 01:26:17,976
and plants alive today
are also threatened.
1261
01:26:18,000 --> 01:26:20,976
It's possible that humanity
is having
1262
01:26:21,000 --> 01:26:23,336
as big an impact on the world
1263
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as the asteroid that ended
the age of the dinosaurs.
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As human beings,
we are unique in our ability
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01:26:31,680 --> 01:26:34,736
to learn from the distant past.
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Now we must use that ability
wisely and do our very best
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to protect the millions of species
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for whom, alongside us,
this planet is home.
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01:27:04,740 --> 01:27:08,240
Re-sync: BLU DUAINE
blu.duaine@protonmail.com
99351
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