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The sunlit waters of a shallow sea.
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Life here is rich and varied.
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Jellyfish, sea gooseberries and all kinds
of larvae drift in the dappled waters.
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On the bottom, sea anemones wave among the
rocks and small worms wriggle within crannies.
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Everywhere you look,
there seems to be life of some kind.
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Creatures like these
have a very ancient ancestry.
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They were among the first
forms of life to appear on earth
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and they existed for several hundred million
years before the development of fish,
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the first animals with backbones.
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But when such creatures with no bones
in them die, what remains of them?
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Almost nothing. Their soft tissues
simply disintegrate and dissolve in the water,
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and there's hardly anything left of them
but a little slime in the mud.
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Only a minority, a few molluscs with hard shells,
crustaceans like crabs with external skeletons,
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only they leave any signs of their existence
after their flesh has vanished.
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So of all that multitude of creatures,
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only one or two could leave behind in the mud
any evidence that they had ever existed.
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This, too, was once mud at the bottom of a sea
but that was over 500 million years ago
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and now it's mudstone
and high in the Canadian Rockies.
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And these rocks, too, contain the remains
of the hard parts of sea animals,
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and very extraordinary animals, too.
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They're now totally extinct
and we call them trilobites.
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But there's virtually nothing else
but trilobites in these rocks,
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so what did the trilobites live on
and, maybe, what hunted the trilobites?
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The answers to questions like those
could only be guesswork
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until, that is, the year 1901.
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In that year, an American geologist,
Charles Walcott,
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was exploring here in the Rocky Mountains
of British Columbia,
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travelling on horseback
with a train of pack mules.
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He was in his 60th year and coming towards
the end of a long and distinguished career
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in which he had made a special study of the
ancient fossil-bearing rocks of North America.
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When he got to this precise point on the trail,
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where this slip of loose rocks crosses it,
one of his horses stumbled.
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Walcott dismounted to clear the path,
and when he did so,
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he hit one of the boulders with his hammer,
as he must have done ten thousand times before.
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Only this time, when the boulder fell apart
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it revealed a fossil the like of which he had
never seen before in all his experience.
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To his amazement,
he saw that it had its soft parts preserved:
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Tentacles, the head and a row of small legs
on either side of its body.
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If he didn't do so then,
he must have realised very soon afterwards
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that this was the most important
discovery of his life.
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So the next season,
he and his sons returned to this place
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to try and find out
where that boulder had come from.
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They climbed up the rock tip,
looking for fossils as they went
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and knowing that the highest level at which
they found any fragments with fossils in them
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must be the place
from which all the fossils were coming.
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And that proved to be just here,
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and this place has been
the site of research ever since.
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A band of these shales just seven foot thick
produced all the fossils.
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Walcott came here for the next eight seasons,
and in that time he collected 61,000 specimens,
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and two-thirds of the species that he found
proved to be new to science.
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Animals such as these, with delicate legs,
with tiny gills and threadlike antennae,
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must have been living throughout the seas
of this very ancient period.
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They had never been seen before
because everywhere else, being soft-bodied,
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they had simply dissolved
and disappeared without trace.
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Only here, for some extraordinary reason,
had they been preserved,
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and preserved, what's more, in amazing detail.
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This was some kind of worm,
presumably a burrower in the mud,
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with an extendible proboscis.
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And here a most remarkable find,
a worm with fleshy legs,
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a possible link between true worms
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and more complex invertebrates
such as centipedes and insects.
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These rocks are known as the Burgess Shales.
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How is it that one thin band of them
on this particular mountainside
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preserved signs of life
that are found nowhere else in the world?
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That was one of the questions Walcott and his
successors spent a long time trying to answer.
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The latest group of scientists
to work on the site here
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come from the Royal Ontario Museum
and are led by Des Collins.
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530 million years ago, this was
a muddy sea floor about 400 feet deep
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and was directly in front of a massive, sheer cliff
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that you can see
in this light-coloured material here.
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The reef front rose
in a sheer cliff about 300 feet high.
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You can see at the top the bedded rock,
which is where the animals lived in a lagoon
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about 100 feet deep or less.
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Every so often, the mud at the top
would come down in a slump,
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picking up the animals, bringing them down here,
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killing them and burying them
and preserving them in the mud.
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This happened at a time when
complex animals had only just appeared,
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so the ultimate ancestors of all life today
must therefore be among them.
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This worm, with an internal rod
running along its length,
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may be the ancestor of all backboned animals.
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And this, with five pairs of claws on its head,
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may be the creature from which scorpions
and spiders have evolved,
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for it shares some of their
most significant characters.
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This, with what seems a protrudable proboscis,
is more of a puzzle.
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It may be related to certain kinds of living worms.
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And this bizarre creature
is quite unlike anything alive today.
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It had seven pairs of legs,
seven tentacles on its back, each with a mouth.
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It seems to have been one of evolution's
experiments that simply didn't work very well,
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and it's left no descendants.
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By examining the best of these specimens,
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it's possible to deduce from the flattened outlines
what it was like before it was squashed flat,
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and to reconstruct it in three dimensions.
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The liquid mud often penetrated
the insides of the animals,
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separating each tiny organ from the other
by a microscopic film of mud particles,
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and then it's possible to work out
details of internal anatomy.
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This creature swam by waving flaps beneath it
and it sensed its food with long feelers.
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But some specimens are so strange,
it's difficult to make head or tail of them.
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This, for example, three or four inches long,
looks like some kind of shrimp,
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except that none
has ever been found with a head.
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And this, rather like a slice of pineapple.
Could this be some kind of jellyfish?
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Though there are still some speculations,
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we now have a picture
of a large and varied community.
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But if there were so many
of these mud munchers and filter feeders,
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there must surely have been some hunter
that preyed on them. What was that?
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That question troubled a British palaeontologist,
Harry Whittington,
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as he worked on some of Walcott's specimens.
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Searching through many thousands of them,
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he found one in which that pineapple slice
seemed to be attached to some other structure.
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What is more, there were
several other specimens rather like it,
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including one that was
not completely cleared of matrix,
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and he started very carefully to investigate it.
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...if you think this is the underside of the body,
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to look and see, is there anything perhaps
attached to the underside
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that goes down into the rock?
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And there was a little area here.
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And using a little drill, you could
very delicately work along the edge here
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and remove flakes of rock.
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And gradually this thing became exposed
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and I realised, particularly when I got to this end
and saw the characteristic spines on it,
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that was this thing
that had been described many years before,
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anomalocaris, the strange shrimp,
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and people thought this was part of an animal
and envisaged it having a little shell here,
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but no whole one had ever been found.
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Now here was one
attached under the front end of this animal.
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Was that an accident? If there was one
one side, there ought to be one the other.
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Indeed, there was a layer in the rock here
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and I exposed parts of that chiselling around here,
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and there exposed is part of the companion one
that was attached there.
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That predator was revealed.
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The headless shrimps were its claws
and the pineapple slice was its muscular mouth.
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This was the terror of the trilobites.
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So now we have an even more complete picture
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of the life that flourished on the sea floor
530 million years ago.
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We knew it must have contained
the ancestors of all subsequent life,
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but now we have some idea
of what they looked like.
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The next exceptionally detailed glimpse
we get of the progress of life
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comes from this valley in southern Germany,
near a village called Solnhofen.
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140 million years ago, that's 400 million years
after the time of the Burgess Shales,
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this part of Europe lay under the sea,
as we know because it's covered by limestone,
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but this valley is lined by cliffs of a special kind.
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When you examine the rock
of these huge towers,
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you see that it's composed
not of thin, horizontal layers of sediment,
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but of curving plates.
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And these are, in fact, the fossilised remains
of sponges and other reef-building organisms
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which, growing one on top of the other,
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over centuries
slowly built these huge, pillar-like reefs.
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While they were living, beneath the sea,
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they sheltered the water
lying between them and the shore
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from the waves and currents of the open ocean
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and they created a shallow lagoon.
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Conditions then must have been rather like
they are today in other shallow tropical lagoons
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where the water evaporates so fast
that it becomes extremely salty,
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and calcium carbonate in solution
starts to precipitate
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as an extremely fine, limy mud, layer upon layer.
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Over millions of years,
the mud compacted and turned to stone.
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The land level rose and the sea drained away.
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The river in the Solnhofen valley eroded
much of it, exposing those coral cliffs again.
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But elsewhere, the limestone remains.
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And now, as stone, those layers
can be separated, where it's weathered,
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into plates almost as thin as paper.
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And where it's not weathered,
it formed a magnificent building stone
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that's been worked in places like these
since Roman times.
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If the rock splits into plates an inch or so thick,
it can be used for roofing.
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Where it's more massive, it's cut into blocks
for masonry of such quality
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that it has been used all over Germany.
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In the 19th century, a local man
discovered yet another use for it.
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If you draw a picture on it with wax pencil,
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you can, using a special ink, take
an almost unlimited number of copies from it.
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He called the process lithography,
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and it was widely used to print illustrations
for a hundred years or more, all over Europe.
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But every now and again,
when the quarrymen come to split a block,
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they open it and find that there's an illustration
already printed within it,
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an illustration that's 140 million years old,
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like this one
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A fish.
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Fossils are not abundant, for few animals could
live in this inhospitable, near-sterile lagoon.
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These fish were swept into it,
past the reefs, by sudden storms.
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But though there are few of them,
their preservation is near-perfect,
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for the storm that carried them in
also stirred up the mud
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and, as they died, that settled back
and covered them like a shroud.
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A fish with grinding teeth,
like a parrot-fish of today,
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which presumably fed in the same way,
pulverising coral to extract the little polyps.
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A kind of garfish.
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A bottom-living ray,
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a species that seems to have survived
almost unaltered until today.
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This lobster, too, had ancestors
that strayed into the Solnhofen lagoon.
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Crustaceans, with their hard external skeletons,
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make excellent subjects for preservation
under these conditions.
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And backboned animals, too,
with their skeletons of bone,
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are also beautifully preserved.
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A turtle, its flesh gone but its bones very clear.
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Another reptile, with an amazingly long body
and an even longer tail.
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Yet, because of the infrequency
of the currents in the lagoon,
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all its bones remained perfectly positioned
while the flesh decayed around them.
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And because of that extreme stillness,
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even a jellyfish settling gently on the limy mud
has left the delicate impress of its soft body.
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Tracks on the lagoon floor
have also remained clear.
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This one was obviously made
by an animal with several long legs.
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The scratches between the footprints
suggest that it also had a spiky tail.
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And it seems to have been lost,
for it's wandering aimlessly about.
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We're looking at the story of one small death
that took place 140 million years ago,
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for here's the body,
complete with that trailing tail.
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It's a horseshoe crab,
virtually identical with the horseshoe crabs
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that still today swim
in the seas off North America.
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Other tracks are not so easily interpreted.
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What about, for example, this extremely rare
but rather mysterious mark?
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Is it perhaps some kind of worm?
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00:17:29,127 --> 00:17:32,756
Well, it seems to have been caused
by an empty ammonite shell
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that fell down into the mud, making a dent,
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and then, carried by a current,
rolled until it came to the mouth again,
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which caused it to leap up, fall again,
and then roll again.
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Insects flying over the lagoon
sometimes flopped into the water and sank.
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A dragonfly.
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A winged grasshopper.
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00:18:01,727 --> 00:18:05,197
And a much bigger flying animal, a pterosaur,
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the membrane of its skinny wings plainly visible.
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But there's one animal in particular,
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whose remains drifted down through the salty
water and settled on the mud of the lagoon,
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00:18:22,927 --> 00:18:27,045
that has made the name Solnhofen
famous worldwide.
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Its remains are so excessively rare,
and so important to science,
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00:18:32,527 --> 00:18:36,998
that they've been called
"the most valuable fossils in the world".
222
00:18:36,847 --> 00:18:40,556
The most perfect of them,
which is kept here in East Berlin,
223
00:18:41,167 --> 00:18:46,366
is so valuable that it's kept locked away
in a safe, away from public view,
224
00:18:46,447 --> 00:18:49,519
and exhibited only as a replica.
225
00:18:49,327 --> 00:18:54,117
This is a rare privilege to see the real thing.
226
00:19:00,207 --> 00:19:05,281
Archaeopteryx, a creature that represents
a link between reptiles and birds.
227
00:19:09,327 --> 00:19:13,764
It's birdlike because it's covered
not by fur but by feathers.
228
00:19:14,127 --> 00:19:19,121
Their intricate structure, each with a central quill
and barbs coming off it on either side,
229
00:19:19,207 --> 00:19:21,198
can be clearly seen.
230
00:19:21,127 --> 00:19:24,722
They are virtually identical to modern feathers.
231
00:19:26,887 --> 00:19:29,321
Its wings are modified front legs,
232
00:19:29,767 --> 00:19:33,123
but not as greatly altered
as the wings of modern birds,
233
00:19:33,127 --> 00:19:36,483
for three of their five toes
still have claws at their tips,
234
00:19:36,607 --> 00:19:39,883
projecting from the front edge of the wings.
235
00:19:44,807 --> 00:19:50,040
The feet had backward-pointing big toes,
which gave the animal a firm grip on a branch,
236
00:19:50,567 --> 00:19:52,956
and that, too, is characteristic of birds.
237
00:19:52,967 --> 00:19:55,765
The head, however, is not at all birdlike.
238
00:19:55,887 --> 00:20:00,438
It had no beak,
but a bony, reptilian jaw lined with teeth.
239
00:20:04,087 --> 00:20:10,276
And here, reptilian and bird characteristics
combined in one feature, the tail.
240
00:20:10,327 --> 00:20:13,319
No bird has bones in its tail like this,
241
00:20:13,687 --> 00:20:17,475
and while reptiles do,
none of them has feathers on it.
242
00:20:17,567 --> 00:20:21,719
In recent years, the question was raised
as to whether these really were feathers,
243
00:20:21,887 --> 00:20:25,084
but the closest examination
of another specimen in London
244
00:20:25,247 --> 00:20:28,284
has proved conclusively that they certainly are.
245
00:20:29,087 --> 00:20:33,205
So, thanks to the limy burial shrouds
of Solnhofen
246
00:20:33,407 --> 00:20:35,398
we can make a detailed reconstruction
247
00:20:35,807 --> 00:20:40,039
of this key creature
in the history of the evolution of life.
248
00:20:45,887 --> 00:20:49,357
But reptiles were still, at this time,
the dominant animals.
249
00:20:49,247 --> 00:20:53,240
Gigantic seagoing crocodiles like this one
roamed the seas.
250
00:20:53,567 --> 00:20:57,355
Huge pterosaurs bigger than any eagle
soared through the air.
251
00:20:57,407 --> 00:21:00,524
And on land, there were the dinosaurs.
252
00:21:00,767 --> 00:21:04,680
The reason we know so much about dinosaurs
is that many were very big,
253
00:21:05,087 --> 00:21:08,636
with tough bones that could survive
being washed down by the rivers
254
00:21:08,447 --> 00:21:11,280
and buried in the deposits of the delta.
255
00:21:11,807 --> 00:21:16,483
But 67 million years ago,
the last of the dinosaurs died.
256
00:21:16,607 --> 00:21:19,644
For some time, the land
was comparatively underpopulated,
257
00:21:19,487 --> 00:21:22,160
but then the early mammals began to spread.
258
00:21:22,367 --> 00:21:25,165
But they were not big creatures
with tough bones
259
00:21:25,247 --> 00:21:29,798
but small animals with delicate skeletons
that were easily destroyed.
260
00:21:30,047 --> 00:21:33,437
Neither did they live in a lagoon
where there were regular deposits,
261
00:21:33,887 --> 00:21:37,243
but on land, where there was virtually none.
262
00:21:37,247 --> 00:21:41,320
So they were comparatively
poor candidates for fossilisation
263
00:21:41,567 --> 00:21:45,162
and we knew very little about them until, at last,
264
00:21:45,407 --> 00:21:49,446
another of these extraordinary
fossil sites was discovered.
265
00:21:50,687 --> 00:21:55,317
At Messel, near Frankfurt, in Germany,
there's a deposit of shales so rich in oil
266
00:21:55,687 --> 00:22:00,078
that quite spontaneously,
they catch fire and burn underground.
267
00:22:00,007 --> 00:22:03,079
The oil comes from the tissues
of animals and plants
268
00:22:03,247 --> 00:22:06,922
living in the lake
that lay here 48 million years ago.
269
00:22:07,087 --> 00:22:10,079
The shales were once
worked commercially for their oil,
270
00:22:10,527 --> 00:22:13,917
but they contain
much more valuable things than that.
271
00:22:15,687 --> 00:22:21,045
48 million years is a comparatively short time
for mud to turn to rock.
272
00:22:21,327 --> 00:22:26,321
Solnhofen limestone is three times as old,
the Burgess Shales over ten times,
273
00:22:26,607 --> 00:22:30,316
and these shales are still soft and moist.
274
00:22:30,407 --> 00:22:33,399
The excavators have spotted
the remains of a fish,
275
00:22:33,287 --> 00:22:38,805
but it mustn't be fully exposed to the air
because if it dries out, it'll disintegrate,
276
00:22:39,047 --> 00:22:43,438
so the slab is carefully cut out
and taken to a laboratory.
277
00:22:46,487 --> 00:22:53,438
There it's kept moist while the compressed mud
is delicately scraped from the flank of the fish.
278
00:23:07,687 --> 00:23:13,637
Once that side has been cleaned
as far as possible, liquid resin is poured over it.
279
00:23:28,087 --> 00:23:31,204
When that sets, it's perfectly transparent,
280
00:23:31,127 --> 00:23:35,837
so now specimens treated in this way
can be worked on from the other side.
281
00:23:43,367 --> 00:23:46,677
Eventually, virtually all the mud can be removed,
282
00:23:46,767 --> 00:23:52,205
and the fragile bones are held firmly
in a block of transparent plastic.
283
00:23:55,487 --> 00:23:59,924
This is one of the early mammals
for which Messel is now famous,
284
00:23:59,807 --> 00:24:04,403
a tiny horse that was no bigger than a spaniel.
285
00:24:12,967 --> 00:24:16,642
Gerhard Storch,
from the Senckenberg Museum in Frankfurt,
286
00:24:16,807 --> 00:24:19,401
is one of the team working on these finds.
287
00:24:19,567 --> 00:24:25,836
Unlike recent horses,
they possess four digits in the forefeet,
288
00:24:25,887 --> 00:24:28,720
one, two, three, four.
289
00:24:28,767 --> 00:24:33,602
- Both legs are there, aren't they?
- Yeah, there are both legs, side by side.
290
00:24:34,047 --> 00:24:38,757
- And perfect little hooves.
- And perfect little hooves, yeah.
291
00:24:38,807 --> 00:24:43,483
The grinding teeth are not tall and high
in the jaw like those of a modern horse,
292
00:24:43,607 --> 00:24:47,998
but low, indicating that the animal
ate soft leaves and fruit,
293
00:24:47,927 --> 00:24:51,556
and that's confirmed by examining the stomach.
294
00:24:52,047 --> 00:24:58,600
With a scanning microscope,
we can investigate the last diet of these horses.
295
00:24:58,727 --> 00:25:05,917
In this specimen,
the gut contained soft leaves from tropical plants.
296
00:25:05,927 --> 00:25:12,605
- So it was living, what, in the woodlands?
- It was living in a dense, tropical forest.
297
00:25:12,807 --> 00:25:17,198
And there are even stranger things in the muds
of Messel than spaniel-sized horses.
298
00:25:17,327 --> 00:25:22,959
This is a mammal that belongs
to a very archaic group close to insectivores
299
00:25:23,087 --> 00:25:25,726
and this group became extinct.
300
00:25:26,567 --> 00:25:30,560
The forelimbs are very small, very reduced.
301
00:25:30,407 --> 00:25:32,875
The hind limbs are long, elongated.
302
00:25:33,287 --> 00:25:37,200
The tail is very long.
It's a world record for mammals.
303
00:25:37,287 --> 00:25:42,042
It consists of about 50 single vertebrae.
304
00:25:42,087 --> 00:25:45,397
And all of these body proportions tell us
305
00:25:45,447 --> 00:25:49,360
that this animal was moving on its hind limbs,
306
00:25:49,847 --> 00:25:55,126
but not in a way that is familiar to us
from kangaroos or jerboas,
307
00:25:55,087 --> 00:26:00,878
running fast and very manoeuvrable
on the hind limbs but with alternating steps.
308
00:26:01,327 --> 00:26:03,887
(ATTENBOROUGH) So really
there's no equivalent alive today?
309
00:26:03,727 --> 00:26:06,639
(STORCH) There is no analogue today.
310
00:26:09,887 --> 00:26:13,516
There is also, believe it or not,
an ancestor of hedgehogs.
311
00:26:13,607 --> 00:26:16,280
The texture of bone on the front of the skull
312
00:26:16,487 --> 00:26:20,116
shows that the flesh there
was particularly thick with blood vessels,
313
00:26:20,287 --> 00:26:24,360
which suggests that there was
some kind of gland or shield on its forehead.
314
00:26:25,287 --> 00:26:28,085
And there are true birds, many kinds,
315
00:26:28,167 --> 00:26:34,003
some so excellently preserved that almost
the only detail you can't make out is their colour.
316
00:26:34,007 --> 00:26:39,559
And not only birds, but bats,
and several kinds of them as well.
317
00:26:42,967 --> 00:26:47,483
But why should so many flying animals
have fallen dead into the lake?
318
00:26:47,967 --> 00:26:54,122
Something must have happened to these bats
while they were hunting on the wing,
319
00:26:54,207 --> 00:26:59,884
and my idea is that there were
poisonous gases on the Messel lake
320
00:26:59,807 --> 00:27:04,403
and a bat which went down drinking
came to such a gas bubble
321
00:27:04,607 --> 00:27:06,837
and fell down to the water's surface.
322
00:27:09,887 --> 00:27:13,721
So, because of those freakish conditions
40 million years ago,
323
00:27:14,207 --> 00:27:16,516
the vanished lake of Messel
now yields evidence
324
00:27:16,607 --> 00:27:20,680
about not only the animals
that swam in its waters and lived in its forests,
325
00:27:20,927 --> 00:27:23,441
but even those that populated the skies.
326
00:27:26,767 --> 00:27:28,758
Los Angeles, in America.
327
00:27:28,687 --> 00:27:32,282
Hardly world-famous for its fossils,
but it should be,
328
00:27:32,527 --> 00:27:35,360
for in the heart of this most modern of cities
329
00:27:35,887 --> 00:27:41,598
is a site that gives another wholly
exceptional picture of a vanished world.
330
00:27:44,527 --> 00:27:46,518
40,000 years ago,
331
00:27:46,927 --> 00:27:51,318
this was the appearance of the land
on which hotels and freeways now stand.
332
00:27:51,247 --> 00:27:55,638
Firm evidence for every single detail
in this most detailed painting
333
00:27:56,047 --> 00:28:01,440
comes from a small park close by
one of the city's main avenues, La Brea.
334
00:28:03,207 --> 00:28:06,324
In one corner of it, through the harmless grass,
335
00:28:06,567 --> 00:28:12,039
oozes a substance that kills - la brea, tar.
336
00:28:16,567 --> 00:28:20,719
It wells up from the ground here
to form these black pools.
337
00:28:20,887 --> 00:28:23,355
When it rains, water lies on top of it,
338
00:28:23,767 --> 00:28:26,645
and it looks like a place
where you might get a drink.
339
00:28:26,647 --> 00:28:31,084
But any animal that came here to do so
would be lucky to escape alive.
340
00:28:30,967 --> 00:28:36,963
Feet sink into the tar, feathers get entangled in it,
and the animal is fatally trapped.
341
00:28:37,207 --> 00:28:40,756
That's been happening
for 40,000 years and more,
342
00:28:41,167 --> 00:28:44,284
and it's still happening today.
343
00:28:53,887 --> 00:28:58,119
Tar, like oil, is derived
from the bodies of animals and plants
344
00:28:58,207 --> 00:29:00,198
that accumulated in swamps.
345
00:29:00,127 --> 00:29:03,722
The sand that was deposited on top of them
squeezed their remains
346
00:29:03,967 --> 00:29:07,198
so that droplets of oil
were expelled from their tissues.
347
00:29:07,327 --> 00:29:11,605
That accumulated in basins
within the texture of the porous sandstone
348
00:29:12,127 --> 00:29:17,485
and then, where there is a fault,
this substance is forced up to the surface.
349
00:29:19,327 --> 00:29:22,717
The earlier flows of tar,
containing the most ancient animals,
350
00:29:22,687 --> 00:29:25,042
have now been covered by later flows,
351
00:29:25,087 --> 00:29:28,921
so to reach them,
you have to dig down into the tar pit,
352
00:29:29,407 --> 00:29:32,763
and excavations which started
back at the beginning of this century
353
00:29:32,767 --> 00:29:35,600
are now being carried on some 30 feet down,
354
00:29:35,647 --> 00:29:39,640
while the tar still rises
around the excavating platform.
355
00:29:40,567 --> 00:29:43,320
The work is supervised by trained scientists,
356
00:29:43,447 --> 00:29:47,565
but most of the team
is made up of local volunteers.
357
00:29:47,727 --> 00:29:51,766
(MAN) 0K. This is ready to go. Got the bag?
(W0MAN) Yes, I do.
358
00:29:52,167 --> 00:29:55,125
(MAN) That's a sabre-toothed cat femur.
(W0MAN) Right or left?
359
00:29:55,527 --> 00:29:57,597
(MAN) That's a right.
360
00:29:57,927 --> 00:30:00,725
(W0MAN) And without his epiphysis.
(MAN) Right.
361
00:30:00,487 --> 00:30:05,117
(MAN) What you got over there, Jerry?
(JERRY) I've got this ulna uncovered here.
362
00:30:05,447 --> 00:30:10,202
- What's it lying on top of?
- It's lying right across a sabre-tooth cat skull.
363
00:30:10,247 --> 00:30:14,923
The finds have been put on display
in a museum recently built on the site,
364
00:30:15,407 --> 00:30:17,443
and very spectacular they are.
365
00:30:28,127 --> 00:30:31,199
In addition to this magnificent imperial mammoth,
366
00:30:31,487 --> 00:30:34,923
the biggest of all the prehistoric elephants
that lived in North America,
367
00:30:35,327 --> 00:30:40,845
there were extinct horses and camels
which grazed on these plains.
368
00:30:43,927 --> 00:30:47,124
Huge, long-horned bison.
369
00:30:49,287 --> 00:30:53,360
There were over 20 species
of eagles and falcons.
370
00:30:54,327 --> 00:30:58,081
Ground sloths the size of small elephants.
371
00:30:58,167 --> 00:31:01,204
These huge animals are now totally extinct.
372
00:31:01,527 --> 00:31:04,963
They browsed the trees and,
like the rest of these plant-eaters,
373
00:31:04,887 --> 00:31:08,357
only rarely and accidentally
strayed into the tar pits.
374
00:31:08,727 --> 00:31:11,639
But once an animal like this
was mired and stuck,
375
00:31:11,607 --> 00:31:15,805
it made the pits a positive attraction
to packs of wolves.
376
00:31:18,847 --> 00:31:22,442
These dire wolves were
about the same size as living wolves
377
00:31:22,487 --> 00:31:24,318
but with more massive heads.
378
00:31:24,407 --> 00:31:28,195
Struggling, trapped animals
were obviously something they couldn't resist,
379
00:31:28,247 --> 00:31:32,604
for wolves, in fact, are the commonest
of all the victims of the tar pits.
380
00:31:34,887 --> 00:31:38,084
The most frequently trapped
grass-eaters were the bison,
381
00:31:38,247 --> 00:31:40,681
so there were probably big herds of them,
382
00:31:40,647 --> 00:31:44,686
but, again, the pits contain more bones
of the animal that preyed on them,
383
00:31:44,967 --> 00:31:47,083
the American lion.
384
00:31:55,287 --> 00:31:58,802
The females were about the same size
as African lions,
385
00:31:59,127 --> 00:32:02,597
but the males were 25% bigger.
386
00:32:09,207 --> 00:32:13,678
And there was an even more impressive cat,
the sabre-tooth.
387
00:32:14,967 --> 00:32:19,245
At one time it was thought that these
extraordinary teeth were daggers for stabbing,
388
00:32:19,447 --> 00:32:24,282
but now it's believed that they were used
to slit open the belly of the prey.
389
00:32:24,247 --> 00:32:28,081
You might wonder how the animal
managed even to close its jaws,
390
00:32:28,407 --> 00:32:32,480
and I asked a scientist at the museum,
George Jefferson, to explain.
391
00:32:32,727 --> 00:32:37,323
I think we can illustrate that best with
the specimen here that was preserved closed.
392
00:32:37,447 --> 00:32:41,360
That will give us an idea
what that mouth looked like.
393
00:32:41,287 --> 00:32:48,477
As you can see, the incisors actually interlaced,
allowing the jaw to fully close.
394
00:32:48,847 --> 00:32:51,042
I'm surprised how much space there is
395
00:32:51,247 --> 00:32:54,796
between those huge sabre teeth
and the lower jaw.
396
00:32:55,007 --> 00:33:01,037
That gap is the same gap as between
the meat-slicing teeth on the side of the face.
397
00:33:00,767 --> 00:33:05,079
What that meant is,
the animal would disengage the incisors,
398
00:33:05,567 --> 00:33:08,843
drop the jaw down, move it slightly sideways,
399
00:33:08,927 --> 00:33:11,725
and guide the slicing blades here
400
00:33:11,767 --> 00:33:17,000
by running the inside of this flange
against the canine tooth.
401
00:33:17,047 --> 00:33:20,244
- Is that a new discovery?
- It is. In fact,
402
00:33:20,607 --> 00:33:25,078
we didn't know this gap was that way
until we found this specimen.
403
00:33:27,327 --> 00:33:32,640
As well as big animals, the tar preserved
a whole range of organisms that lived here.
404
00:33:32,607 --> 00:33:35,075
Even pollen grains can be obtained from it,
405
00:33:35,487 --> 00:33:39,719
and it's they that have enabled the artist
who painted the reconstructed landscape
406
00:33:39,807 --> 00:33:45,120
to show the correct species
of flowering bush, Californian sage.
407
00:33:48,927 --> 00:33:52,203
The museum's laboratory
is surrounded by glass windows,
408
00:33:52,287 --> 00:33:56,519
so that those working on the finds
become exhibits themselves.
409
00:33:57,087 --> 00:33:59,840
I think this rib's going in like that,
410
00:34:00,327 --> 00:34:03,444
and if you look at the top,
the way it angles round,
411
00:34:03,687 --> 00:34:08,238
- I think there's probably a little edge.
- So it's going back under.
412
00:34:08,007 --> 00:34:12,603
Once you've discovered what animals
were present, why go on digging up more?
413
00:34:12,887 --> 00:34:16,562
Well, the museum has over 200 jaws of bison.
414
00:34:16,927 --> 00:34:20,966
As George Jefferson explained,
their sheer number gives new information.
415
00:34:20,767 --> 00:34:22,758
With these three specimens here,
416
00:34:23,167 --> 00:34:27,285
we can see an animal three years old,
two years old and one year old.
417
00:34:28,927 --> 00:34:33,205
We can tell that
from the eruption stage of the teeth.
418
00:34:33,327 --> 00:34:38,162
Here we see this tooth being pushed out -
this animal is three years old.
419
00:34:38,127 --> 00:34:41,005
We don't have specimens
representing intermediate ages
420
00:34:41,007 --> 00:34:45,603
between three years old and two years old,
nor two and one year old.
421
00:34:46,087 --> 00:34:50,763
That tells us that these animals are coming here
periodically at a certain time of year.
422
00:34:50,887 --> 00:34:55,915
We can determine that season by comparing
the stage of wear on these teeth
423
00:34:56,167 --> 00:34:59,637
with modern bison who have
a very restricted calving period.
424
00:34:59,527 --> 00:35:01,438
They're here in the late springtime.
425
00:35:01,927 --> 00:35:03,519
- So they're migrating?
- Yes.
426
00:35:05,087 --> 00:35:09,126
The multitudes of jaws, therefore,
prove that once in California,
427
00:35:08,927 --> 00:35:12,283
great herds of bison
made long migratory journeys,
428
00:35:12,767 --> 00:35:17,443
and that every year, after the rains, when the
grass began to sprout on the Hollywood hills,
429
00:35:17,567 --> 00:35:20,843
there was great carnage around the tar pits.
430
00:35:31,447 --> 00:35:35,918
The sheer abundance of the dire-wolf skulls
also yields information.
431
00:35:36,167 --> 00:35:41,480
They are not, of course, all the same,
and the differences are not all due to age.
432
00:35:41,327 --> 00:35:47,038
The lumps and distortions that are apparent,
compared to the smooth forehead on this animal,
433
00:35:47,647 --> 00:35:50,878
indicate an infection
in the frontal sinuses of the forehead,
434
00:35:51,447 --> 00:35:55,486
probably as the result
of being kicked in the face,
435
00:35:55,527 --> 00:35:58,325
maybe by a bison or a camel.
436
00:35:58,647 --> 00:36:02,196
This animal was obviously
going after its prey and getting injured.
437
00:36:02,967 --> 00:36:05,561
We also see injuries in the sabre cats.
438
00:36:06,807 --> 00:36:09,526
We see chronic injuries to the back.
439
00:36:11,127 --> 00:36:15,245
Here we have three lumbar or back vertebrae
440
00:36:15,327 --> 00:36:19,286
that have been fused together
by a mass of bony tissue.
441
00:36:19,527 --> 00:36:24,442
This bony tissue grows along the ligaments
and muscles where they're injured and stretched
442
00:36:24,327 --> 00:36:26,966
while this animal is lunging for its prey.
443
00:36:30,967 --> 00:36:32,958
In this hip...
444
00:36:34,407 --> 00:36:38,480
...we have a fairly normal hip socket here,
445
00:36:38,247 --> 00:36:43,640
but on this side you can see a lot of knobbly bone,
446
00:36:44,007 --> 00:36:46,805
a distortion and break,
447
00:36:46,887 --> 00:36:50,641
there are flanges of extra bone in here.
448
00:36:50,727 --> 00:36:55,039
This animal was obviously in a lot of pain
while this healing was going on.
449
00:36:55,527 --> 00:36:59,202
We think it may have been butted
by a bison, hit very hard,
450
00:36:59,367 --> 00:37:01,927
or even, possibly, by a mammoth elephant.
451
00:37:01,767 --> 00:37:04,076
- So he's really a cripple.
- Yes.
452
00:37:04,647 --> 00:37:07,081
It's astounding it lived as long as it did.
453
00:37:07,047 --> 00:37:10,517
Some researchers believe this is evidence
454
00:37:10,527 --> 00:37:16,477
that the injured and infirm were being tolerated
within the population and possibly cared for.
455
00:37:16,767 --> 00:37:19,964
- So social behaviour among the sabre cats?
- Social behaviour.
456
00:37:22,167 --> 00:37:25,239
It seems almost miraculous
that any remains of animals
457
00:37:25,527 --> 00:37:30,555
could survive for tens of thousands of years,
let alone hundreds of millions.
458
00:37:30,607 --> 00:37:35,840
In exceptional circumstances, like the tar pits
of La Brea or the volcanic lake of Messel,
459
00:37:36,367 --> 00:37:41,885
the hot lagoons of Solnhofen and the muddy
submarine avalanches of the Burgess Shales,
460
00:37:42,007 --> 00:37:45,238
they leave clues that tell us
not only about their appearance,
461
00:37:45,367 --> 00:37:51,681
but their detailed internal anatomy,
their daily habits, even their social life.
462
00:37:51,607 --> 00:37:54,997
Fossils have been forming
ever since life appeared on this planet
463
00:37:55,447 --> 00:37:58,007
and lie in the earth all around us.
464
00:37:57,847 --> 00:38:03,524
They provide us with irrefutable and wonderful
evidence of what existed before we did.
465
00:38:05,527 --> 00:38:09,679
Sometimes the latest high-tech apparatus
is needed to reveal it,
466
00:38:09,847 --> 00:38:13,362
sometimes it needs nothing more
than a simple blow from a hammer
467
00:38:13,207 --> 00:38:15,482
and logical, clear-minded thought.
468
00:38:16,087 --> 00:38:17,884
But slowly, piece by piece,
469
00:38:18,007 --> 00:38:21,716
we're putting together
the history of the long procession of life
470
00:38:21,847 --> 00:38:25,078
that preceded mankind's appearance
upon this planet,
471
00:38:25,207 --> 00:38:28,279
and of which, indeed, we are a part.