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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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[grunts]
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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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[bellowing, rumbling]
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[David Attenborough]
This time on Prehistoric Planet,
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- we reveal new animals...
- [roars]
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...and new insight
into their quest to find a partner...
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[chirps]
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...the challenges faced by raising a family...
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[bellows]
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...and their titanic battles.
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[rumbling]
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[bellows]
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[roars]
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- [roars]
- [squawking]
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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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[animal grunting]
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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.
- [animal bellowing]
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[grunts]
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[rumbling]
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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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[rumbling]
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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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[groans]
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[breathing heavily]
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He may not survive the night.
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[bellowing]
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[animal grunting]
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Dawn.
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And these troodontids
have picked up a scent.
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[sniffing]
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They're quick to investigate anything new...
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- [grunting]
- ...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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- [grunts]
- [Attenborough] Very frustrating.
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[animal rumbling]
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[shrieks]
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Tyrannosaurus rex...
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[grunts, growls]
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...North America's top predator.
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[tyrannosaur grunts, bites]
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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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[tyrannosaur rumbles]
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[grunts]
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[snarls]
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[grunting]
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[roars]
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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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[rumbles]
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[roars]
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[hisses, snarls]
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Quetzalcoatlus, a giant pterosaur.
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[grunts, roaring]
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One of the few creatures
that will challenge an adult tyrannosaur.
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[snarls]
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[grunting]
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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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[grunts]
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[growls]
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Even so,
it seems that he's not going to back down.
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- [rumbling]
- [pterosaur 2 growls]
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[grunts]
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But the arrival
of a second Quetzalcoatlus...
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[growls]
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...changes the odds.
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[rumbling]
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- [pterosaur growls]
- [snarls]
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After all,
two beaks are deadlier than one.
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[all snarling]
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For T. rex, this is now too dangerous.
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[tyrannosaur rumbles]
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[growling]
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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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[birds squawking]
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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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[squawking]
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And they're not alone.
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Dinosaurs are here too.
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[grunting]
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A family of Pectinodon.
They're feathered but flightless.
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[growls, grunting]
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And they're led by their father.
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[grunting]
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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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[buzzing]
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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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[grunting]
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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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[buzzing]
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[grunting]
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[whistling]
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[both grunt]
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But their father has
his eyes on a bigger prize.
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- [troodontid growls]
- [squawks]
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Pectinodon are not only intelligent,
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they're also very skillful hunters.
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[squawking]
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The Styginetta are
unaware of his approach.
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[groaning]
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- Success.
- [grunting]
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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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[animals growling]
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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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[distant bellowing]
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As spring arrives,
strange calls echo through the trees.
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[bellowing continues]
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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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[dinosaur bellowing]
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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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[bellowing]
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The six-ton males fight
and display their strength.
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[bellows]
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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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00:22:18,672 --> 00:22:22,926
These gatherings are crucial events
in the lives of Triceratops.
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00:22:25,637 --> 00:22:30,642
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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[grunting, rumbling]
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[bellows]
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A 30-year-old male
weighing more than ten tons.
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00:22:59,963 --> 00:23:02,382
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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00:23:05,886 --> 00:23:08,388
[bellowing]
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00:23:11,475 --> 00:23:12,559
He may be old,
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00:23:12,559 --> 00:23:16,563
but he's still strong enough
to challenge a young rival, however fit.
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[grunting]
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00:23:20,776 --> 00:23:22,110
[bellowing]
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00:23:24,404 --> 00:23:25,739
[huffs]
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00:23:29,952 --> 00:23:31,161
The stakes are high,
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00:23:32,913 --> 00:23:35,541
and neither is willing to back down.
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00:23:45,968 --> 00:23:47,427
[bellowing]
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00:23:57,312 --> 00:23:59,273
[grunting]
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00:24:06,321 --> 00:24:09,741
The veteran
has a four-ton weight advantage...
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00:24:09,741 --> 00:24:10,909
[bellowing]
227
00:24:12,536 --> 00:24:14,580
...and the skill to make it count.
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00:24:17,708 --> 00:24:18,792
[huffs]
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00:24:19,918 --> 00:24:23,380
The youngster's horns
are no longer perfect.
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00:24:29,052 --> 00:24:30,637
[bellows]
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00:24:34,808 --> 00:24:36,894
[bellowing]
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00:24:54,953 --> 00:24:57,414
The old bull's fighting prowess
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00:24:57,414 --> 00:25:00,584
certainly seems to have impressed
this female.
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00:25:16,099 --> 00:25:19,645
For the loser, the mating season is over.
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00:25:23,190 --> 00:25:28,362
However, his newly won battle scars
might be just enough to attract a female
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00:25:28,362 --> 00:25:31,865
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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[huffs]
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00:26:56,992 --> 00:26:58,702
After a tough winter,
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00:26:58,702 --> 00:27:02,998
this female Nanuqsaur
needs to make a kill soon.
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00:27:08,545 --> 00:27:14,051
A smaller relative of T. rex,
but more agile and, critically, faster.
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00:27:18,514 --> 00:27:22,768
There is nowhere to hide,
so a surprise attack is impossible.
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00:27:30,275 --> 00:27:34,279
Instead, she resorts to creating panic.
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00:27:53,507 --> 00:27:56,093
She needs to pick out a single target...
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00:27:58,887 --> 00:28:00,430
and stick with it.
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00:28:13,902 --> 00:28:18,073
The Ornithomimus' bursts of speed
just give them the edge.
258
00:28:20,325 --> 00:28:21,994
[bellows]
259
00:28:24,037 --> 00:28:27,749
Each failed hunt
uses up more precious energy...
260
00:28:31,336 --> 00:28:34,173
bringing her ever closer to starvation.
261
00:28:40,596 --> 00:28:41,680
It may be spring,
262
00:28:41,680 --> 00:28:46,894
but this far north, freezing winds
can quickly cause temperatures to fall.
263
00:29:15,506 --> 00:29:21,595
Flurries of snow and a rocky outcrop
could give the Nanuqsaur a second chance.
264
00:29:29,186 --> 00:29:31,396
Now she's harder to spot.
265
00:29:36,401 --> 00:29:39,947
Every inch forward
brings her closer to success.
266
00:29:46,912 --> 00:29:48,747
[muffled footsteps approaching]
267
00:29:52,417 --> 00:29:53,627
[Ornithomimus screeches]
268
00:30:18,360 --> 00:30:20,445
She selects her target.
269
00:31:07,367 --> 00:31:10,078
This prize is not only for her.
270
00:31:12,164 --> 00:31:14,166
[chittering]
271
00:31:19,046 --> 00:31:20,631
She is a mother.
272
00:31:29,223 --> 00:31:31,391
Fresh meat for her youngsters.
273
00:31:33,310 --> 00:31:35,562
Perhaps the first for many weeks.
274
00:31:46,698 --> 00:31:48,867
If her babies are to thrive,
275
00:31:48,867 --> 00:31:53,664
she will have to repeat today's success
over and over again.
276
00:31:58,043 --> 00:32:01,964
Until her young are old enough
to join her in the hunt
277
00:32:01,964 --> 00:32:05,467
and eventually fend for themselves.
278
00:32:12,057 --> 00:32:16,854
Here, in this remote
and perhaps most challenging frontier
279
00:32:17,354 --> 00:32:19,648
of the North American continent,
280
00:32:20,232 --> 00:32:22,568
66 million years ago.
281
00:32:44,047 --> 00:32:49,386
This is one of the most dramatic skulls
from our prehistoric planet.
282
00:32:50,095 --> 00:32:55,475
It belonged to a plant-eating dinosaur
called Triceratops.
283
00:32:56,560 --> 00:32:59,980
[rumbling, bellowing]
284
00:33:00,647 --> 00:33:03,817
This dinosaur is instantly recognizable
285
00:33:04,735 --> 00:33:07,821
from the massive frill
at the back of its head.
286
00:33:11,366 --> 00:33:14,912
But 140 years after
the first fossil was found,
287
00:33:14,912 --> 00:33:17,206
scientists are still asking,
288
00:33:18,707 --> 00:33:21,084
"What was the frill for?"
289
00:33:23,128 --> 00:33:24,546
[professor]
These were enormous structures,
290
00:33:24,546 --> 00:33:27,549
{\an8}so it's an enormous investment
in bone and in tissue
291
00:33:27,549 --> 00:33:30,636
{\an8}and also in the muscular effort
to hold these structures up.
292
00:33:31,595 --> 00:33:34,515
All of this investment must mean
that these features are very important
293
00:33:34,515 --> 00:33:35,933
to the animal's way of life.
294
00:33:37,142 --> 00:33:38,143
[Attenborough] But how?
295
00:33:38,143 --> 00:33:39,520
[grunts]
296
00:33:41,396 --> 00:33:45,108
Evidence of injury
on Triceratops fossils suggests
297
00:33:45,108 --> 00:33:49,196
that the frills were important
in defense and combat.
298
00:33:51,281 --> 00:33:53,867
{\an8}We can see, um, lesions on the skull
299
00:33:53,867 --> 00:33:56,662
{\an8}which are areas where
the skull has been damaged and healed.
300
00:33:58,497 --> 00:34:03,001
We can also see where a predator
has taken a chunk out of a frill.
301
00:34:03,752 --> 00:34:07,714
That might indicate that we're looking
at some sort of defensive structure.
302
00:34:11,844 --> 00:34:13,594
But the story doesn't end there.
303
00:34:17,224 --> 00:34:22,980
Another possibility is that the frill
was used to attract prospective mates.
304
00:34:25,815 --> 00:34:27,650
We see this in living animals
305
00:34:27,650 --> 00:34:30,821
where structures like horns
show off how healthy they are
306
00:34:30,821 --> 00:34:34,032
and who's a good prospect
for producing lots of young.
307
00:34:34,032 --> 00:34:35,534
[bellowing]
308
00:34:37,536 --> 00:34:38,620
[Attenborough] For a moose,
309
00:34:38,620 --> 00:34:42,623
having large antlers makes
the male more attractive.
310
00:34:43,166 --> 00:34:46,043
Vital when it reaches sexual maturity.
311
00:34:49,672 --> 00:34:52,967
Could the same apply to
the Triceratops' frill?
312
00:34:55,094 --> 00:34:56,679
[Maidment] If it was only for defense,
313
00:34:56,679 --> 00:34:58,849
then we would expect to see them develop
314
00:34:58,849 --> 00:35:02,352
to the same degree
in juveniles as in adults, but we don't.
315
00:35:03,937 --> 00:35:05,814
{\an8}We see them being much smaller
in the juveniles
316
00:35:05,814 --> 00:35:08,859
{\an8}and not really developing
into the very, very large structures
317
00:35:08,859 --> 00:35:10,527
{\an8}of the adults until much later.
318
00:35:12,821 --> 00:35:14,907
{\an8}[Attenborough]
This isn't the only evidence
319
00:35:14,907 --> 00:35:17,409
{\an8}that they were used in sexual display.
320
00:35:18,827 --> 00:35:21,914
The surfaces of the frills
are very heavily grooved.
321
00:35:22,456 --> 00:35:25,125
These grooves probably carried nerves
and blood vessels
322
00:35:25,125 --> 00:35:28,253
that would have supplied
the skin growing over those frills.
323
00:35:30,047 --> 00:35:31,673
This may have been very brightly colored,
324
00:35:31,673 --> 00:35:35,719
a big surface area for the animal
to show off to potential mates.
325
00:35:42,851 --> 00:35:45,020
[Attenborough] Scientists now believe that
326
00:35:45,020 --> 00:35:50,234
the Triceratops' best-known feature
was truly multipurpose.
327
00:35:52,444 --> 00:35:54,655
Very useful for attack and defense...
328
00:35:59,952 --> 00:36:03,080
but also ideal for attracting a mate.
329
00:36:07,960 --> 00:36:09,461
[bellows]
330
00:36:09,461 --> 00:36:14,591
It would have been
an awe-inspiring sight to friend or foe.
331
00:36:17,052 --> 00:36:19,471
[grunting, rumbling]
332
00:36:22,432 --> 00:36:24,935
[bellows]