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{\an8}Dinosaurs ruled the planet
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{\an8}for over 150 million years.
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They occupied almost every corner
of the globe
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and came in almost
every shape and size imaginable.
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Some were truly extraordinary.
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We now know that T. rex was
a powerful swimmer.
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Velociraptors were cunning,
feathered hunters,
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and that some dinosaurs had
the most bizarre behavior.
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But new discoveries
are being made almost every day
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that tell us more about life
on this planet 66 million years ago.
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This time on Prehistoric Planet,
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we reveal new animals...
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and new insight
into their quest to find a partner,
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the challenges faced by raising a family...
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and their titanic battles.
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Journey to a time
when nature put on its greatest show.
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This is Prehistoric Planet 2.
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The coast of the vast inland sea
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that almost splits North America in half.
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Here in the south, as the tide falls,
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giants are drawn to the shoreline.
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These Alamosaurs are a hundred feet long
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and weigh some 80 tons.
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They are the largest dinosaurs
on the continent.
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So huge that no predator can tackle them.
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Some live to a great age.
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This male is around 70 years old.
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Many in the herd
are likely to be his offspring.
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But his long life is now coming to an end.
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His immense body is beginning to fail him.
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He may not survive the night.
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Dawn.
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And these troodontids
have picked up a scent.
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They're quick to investigate anything new...
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especially if it might be worth eating.
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But biting through a three-inch-thick hide
is beyond their power.
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Very frustrating.
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Tyrannosaurus rex...
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North America's top predator.
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With his six-inch-long teeth,
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tearing through an Alamosaur's
tough skin is not a problem.
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T. Rex might be able to bully troodontids,
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but a carcass as big as this
soon attracts more formidable competition.
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Quetzalcoatlus, a giant pterosaur.
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One of the few creatures
that will challenge an adult tyrannosaur.
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One strike from its six-foot-long beak
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could easily cost T. rex an eye.
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Even so,
it seems that he's not going to back down.
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But the arrival
of a second Quetzalcoatlus...
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changes the odds.
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After all,
two beaks are deadlier than one.
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For T. rex, this is now too dangerous.
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Some fights just aren't worth the risk.
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For now, the flying giants have won.
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They quickly eat all they can.
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But T. rex will almost certainly be back
to claim his share
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once his flying rivals leave.
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In the waters that surround North America,
there are other giant predators.
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But they have no rivals.
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Mosasaurs.
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They may look like huge sharks,
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but they are in fact
a kind of aquatic lizard.
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Size, speed and powerful jaws mean
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that very few creatures
in the ocean are safe from these hunters.
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In the Gulf of Mexico,
this Globidens mosasaur is searching
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for one particular kind of prey.
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Tiger ammonites, Sphenodiscus.
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Every year, huge shoals of females come up
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from deep water
and travel towards the coast.
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They have all recently mated and each is
now carrying hundreds of fertilized eggs.
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The eggs must be laid in the shallows.
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And that is where the mosasaur is waiting.
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Tiger ammonites are themselves hunters.
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The combination of a streamlined profile
and a powerful siphon enables them
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to shoot through the water at great speed.
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But so can the mosasaur.
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Globidens has broad, rounded teeth
that easily crack the ammonites' shell,
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releasing the air that keeps them buoyant.
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Without it,
they sink helplessly to the seabed.
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Before the ammonites can escape,
the mosasaur disables as many as it can.
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Finally, time to tuck in.
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Globidens may have killed dozens...
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but even this makes only a small impact
on the overall numbers of ammonites.
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Most of the shoal have survived
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and continue on their journey
to their spawning grounds.
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The rocky seabed here
has many cracks and crevices,
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ideal places for attaching
the ammonites' precious egg sacs.
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The females then abandon them.
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But safe in this coastal nursery,
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these eggs will produce
the next generation.
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These coastal seas are full of life.
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Yet on land,
and only a few hundred miles away,
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there is desolation.
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Here, powerful movements deep
in the earth's crust are beginning
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to raise the Rocky Mountains.
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The immense changes in the landscape
have cut off this lake from nearby rivers.
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Its waters evaporate in the strong winds
and intense summer sun.
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And the minerals that are dissolved in it
are beginning to reach toxic levels.
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For most, this water is simply
too poisonous to drink.
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Even so, every year this place is visited
by all kinds of animals.
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Flocks of Styginetta,
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a primitive relative of ducks,
stop here on their travels.
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And they're not alone.
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Dinosaurs are here too.
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A family of Pectinodon.
They're feathered but flightless.
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And they're led by their father.
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These dinosaurs
and the Styginetta are both drawn here
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by a strange seasonal bonanza.
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Flies.
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The larvae of these insects are able
to filter out the lake's toxic salts,
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and, as a consequence,
they thrive in immense numbers.
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Now they're hatching into adults...
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in their millions.
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They are a rich and abundant source
of protein for all the lake's visitors.
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Pectinodon are
particularly intelligent dinosaurs.
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It doesn't take them long to work out
the best way to collect flies.
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But their father has
his eyes on a bigger prize.
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Pectinodon are not only intelligent,
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they're also very skillful hunters.
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The Styginetta are
unaware of his approach.
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Success.
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A rather more
substantial meal for the family,
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and just as well.
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The flies will only be here for so long.
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And the dinosaur family
will be forced to find food elsewhere.
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Further north,
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the Rocky Mountains
are still slowly rising.
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And as they do,
they create higher, cooler landscapes
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where vast pine forests flourish.
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As spring arrives,
strange calls echo through the trees.
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The mating season has arrived
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for one of North America's
most heavily armed dinosaurs.
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Triceratops.
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Every year, large numbers
of these giants gather in clearings.
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The females have come to choose a mate.
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The six-ton males fight
and display their strength.
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This young male
looks to be in prime condition.
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Showing off
his spectacular meter-long horns...
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and his colorful head-frill.
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His horns appear perfect.
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Not yet damaged by battle.
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To a female, however,
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the absence of any wear and tear might
suggest a potentially critical weakness.
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A lack of experience.
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These gatherings are crucial events
in the lives of Triceratops.
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They provide the best chance in the whole
year for the adults to become parents.
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And young hopefuls are not
the only ones here.
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A 30-year-old male
weighing more than ten tons.
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If there's one thing
that he has in spades,
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it's decades of wear and tear.
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He may be old,
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but he's still strong enough
to challenge a young rival, however fit.
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The stakes are high,
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and neither is willing to back down.
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The veteran
has a four-ton weight advantage...
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and the skill to make it count.
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The youngster's horns
are no longer perfect.
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The old bull's fighting prowess
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certainly seems to have impressed
this female.
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For the loser, the mating season is over.
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However, his newly won battle scars
might be just enough to attract a female
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next time the herds gather here to mate.
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For plant-eating dinosaurs
like Triceratops,
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the vast forests that cover much of
North America offer plenty to eat
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all year round.
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But for those that live in
the cold far north of the Americas,
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food is much harder to come by.
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Here within the Arctic Circle,
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for three months of the year,
the sun barely rises.
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When its warmth finally returns
after the long winter...
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feathered Ornithomimus
are quick to take advantage.
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These fleet-footed travelers are among
the fastest runners of all dinosaurs.
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Capable of covering vast distances
in search of fresh vegetation.
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They're so fast that they're
very difficult for predators to catch.
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After a tough winter,
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this female Nanuqsaur
needs to make a kill soon.
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A smaller relative of T. rex,
but more agile and, critically, faster.
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There is nowhere to hide,
so a surprise attack is impossible.
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Instead, she resorts to creating panic.
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She needs to pick out a single target...
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and stick with it.
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The Ornithomimus' bursts of speed
just give them the edge.
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Each failed hunt
uses up more precious energy...
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bringing her ever closer to starvation.
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It may be spring,
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but this far north, freezing winds
can quickly cause temperatures to fall.
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Flurries of snow and a rocky outcrop
could give the Nanuqsaur a second chance.
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Now she's harder to spot.
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Every inch forward
brings her closer to success.
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She selects her target.
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This prize is not only for her.
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She is a mother.
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Fresh meat for her youngsters.
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Perhaps the first for many weeks.
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If her babies are to thrive,
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she will have to repeat today's success
over and over again.
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Until her young are old enough
to join her in the hunt
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and eventually fend for themselves.
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Here, in this remote
and perhaps most challenging frontier
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of the North American continent,
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66 million years ago.
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This is one of the most dramatic skulls
from our prehistoric planet.
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It belonged to a plant-eating dinosaur
called Triceratops.
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This dinosaur is instantly recognizable
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from the massive frill
at the back of its head.
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But 140 years after
the first fossil was found,
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scientists are still asking,
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"What was the frill for?"
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These were enormous structures,
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{\an8}so it's an enormous investment
in bone and in tissue
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{\an8}and also in the muscular effort
to hold these structures up.
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All of this investment must mean
that these features are very important
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to the animal's way of life.
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But how?
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Evidence of injury
on Triceratops fossils suggests
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that the frills were important
in defense and combat.
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{\an8}We can see lesions on the skull
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{\an8}which are areas where
the skull has been damaged and healed.
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We can also see where a predator
has taken a chunk out of a frill.
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That might indicate that we're looking
at some sort of defensive structure.
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But the story doesn't end there.
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Another possibility is that the frill
was used to attract prospective mates.
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We see this in living animals
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where structures like horns
show off how healthy they are
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and who's a good prospect
for producing lots of young.
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For a moose,
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having large antlers makes
the male more attractive.
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Vital when it reaches sexual maturity.
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Could the same apply to
the Triceratops' frill?
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If it was only for defense,
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then we would expect to see them develop
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to the same degree
in juveniles as in adults, but we don't.
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{\an8}We see them being much smaller
in the juveniles
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{\an8}and not really developing
into the very, very large structures
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{\an8}of the adults until much later.
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{\an8}This isn't the only evidence
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{\an8}that they were used in sexual display.
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The surfaces of the frills
are very heavily grooved.
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These grooves probably carried nerves
and blood vessels
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that would have supplied
the skin growing over those frills.
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This may have been very brightly colored,
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a big surface area for the animal
to show off to potential mates.
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Scientists now believe that
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the Triceratops' best-known feature
was truly multipurpose.
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Very useful for attack and defense...
246
00:35:59,952 --> 00:36:03,080
but also ideal for attracting a mate.
247
00:36:09,545 --> 00:36:14,591
It would have been
an awe-inspiring sight to friend or foe.