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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 vast swamplands of northeast Asia.
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Within this low-lying flooded territory,
there are countless islands.
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Each of them is surrounded
by slow-moving waters...
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and that makes them potential sanctuaries
for new life.
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A young pterosaur, an azhdarchid.
Just a few hours old.
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Being on an island
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means that she's able to take
her first tentative steps in safety.
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Having found her feet,
it's time to try out her wings.
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Getting them to work properly
will take some practice.
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Although she's only 1-foot tall,
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she will grow into a giant
with a 30-foot wingspan.
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And to do that
will require plenty of food...
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something this tiny island can't provide.
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She will have to leave
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to feed in the swampy forests
that surround her island.
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Maiden flights are always tricky,
especially when they're over open water.
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Today there is a light breeze.
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That will help by giving some extra lift.
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But this youngster
is not yet strong enough.
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Shamosuchus. Fifteen-feet-long predators.
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This island might offer safety,
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but the surrounding waters
certainly do not.
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If the takeoff isn't perfect,
it's difficult to gain height.
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And this is not high enough.
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Some of the stronger flyers
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have almost reached the safety
of the forest.
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Others have still to make their attempt.
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A near-miraculous escape.
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And now the chance to collect her rewards.
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In these rich swamp forests,
there's all the food she needs.
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Here in the wetlands of South America,
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long summer days
are fueling a greater feast.
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These swamps are teeming
with animals of all kinds.
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And hunters are gathering.
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The ferocious three-foot-long garfish.
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Lunch for a giant Austroraptor.
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They are relatives of Velociraptors
but much, much bigger.
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Twenty feet from head to tail
and weighing over 800 pounds.
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And with teeth
not unlike those of a crocodile,
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these dinosaurs are very skilled
at catching fish.
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For most of the year,
they're solitary hunters.
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But as the number of fish increases
during summer,
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so does the number of Austroraptors.
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The biggest try to keep
the best fishing spots for themselves.
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They won't tolerate rivals.
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For those not yet in their prime,
it's a challenging time of year.
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This young male,
still in his juvenile colors,
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has little hope
of securing a good place to fish.
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However, there are other ways
of getting a meal here.
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With so much food around,
the adults are very wasteful feeders.
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They often eat
only the choicest parts of the fish.
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And for a youngster,
any leftovers will do very nicely.
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But it's risky.
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To succeed, he will have to be sneaky.
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Bruised and empty-handed.
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But with the adults
still feasting around him,
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there might be another opportunity.
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Two adults fighting
over the best fishing spot.
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Time for the youngster to make a move...
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and time to leave.
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Success.
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And more than just scraps.
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A lesson learnt.
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And when the good conditions
return next year,
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perhaps he'll be able to challenge
for a fishing spot of his own.
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In northern Madagascar,
conditions are already changing.
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The first rain in months
is reviving the parched land.
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As pools and channels refill,
the animals return.
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And they're not all dinosaurs.
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Lurking in these muddy pools...
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is a monster.
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Beelzebufo, the devil toad.
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It's so big it can swallow
a small dinosaur whole.
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But this male isn't here to hunt.
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He is looking for a mate.
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Female devil toads are fussy,
so he needs to find a good spot.
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Only then will he be able
to entice them in.
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His deep croaks travel far and wide.
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This isn't quite what he was hoping for.
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Fifty-foot-long rapetosaurs.
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They have been attracted here
by the promise of a mud bath.
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For Beelzebufo,
their timing couldn't be much worse.
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His pools now lie
beneath 70 tons of sauropod.
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Time is short.
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Female devil toads will only mate
at the start of the rainy season.
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He needs a new pool.
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There's one.
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Reaching it will be dangerous.
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Finally he's got there...
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but he's been noticed.
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He's not known as a devil toad
for nothing.
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Time to try more singing...
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but he can't make himself heard
above the sound of satisfied sauropods.
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Luckily for him,
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there's one thing that rapetosaurs enjoy
even more than wallowing in mud...
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and that is food.
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The hungry herd moves on...
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although, not without leaving
something useful behind.
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Dozens of giant footprints, full of water.
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Perfect for a Beelzebufo
to continue his quest for a mate.
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A devil toad can only survive here
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because every year
the land is flooded by seasonal rains.
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However, there are places
where changing climate
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means the rains are less certain.
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This inland basin in North America was,
in the past, several feet deep in water.
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But after a decade of drought,
it's now bone dry.
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Nonetheless,
some dinosaurs still linger here.
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A herd of pachycephalosaurs,
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bizarre creatures with thick,
dome-shaped skulls.
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They prefer to feed on fruit and leaves...
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but now they are forced
to make do with roots and insects.
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The herd is led by a large male.
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He keeps order, so everyone
is able to search for food in peace.
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But trouble is brewing within the herd.
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The young male
is throwing his weight around.
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It's time for the dominant male
to put him in his place or kick him out.
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He flaunts his colorful headgear...
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trying to intimidate the youngster.
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But he's not going to back down
that easily.
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Ten-inch-thick skulls enable them
to survive powerful, head-on collisions.
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The older male is heavier,
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but the younger is more agile
and has more stamina,
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and that tips the balance in his favor.
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A bellow of victory.
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But too soon.
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The loser has to pay a heavy price.
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Exile.
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Alone,
it will be a struggle to fend for himself.
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But life here will not be easy
for the winner either
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unless the water returns
to this land and soon.
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Across this vast continent,
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there are over 100,000 square miles
of swamplands...
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and most of them
remain flooded all year round.
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Here in spring,
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new plant growth creates excellent
feeding grounds for the gathering herds.
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But where there are large numbers
of plant eaters...
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there are great hunters.
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T. Rex...
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the most powerful land predators
on the planet.
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They usually ambush their prey...
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but with so many watching eyes...
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this is not the right time to attack.
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As darkness falls,
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some of the herds
that had been grazing out in the open
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retreat into the forest for shelter.
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Now the odds switch in favor
of the predators.
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Tyrannosaurs have the largest eyes
of any dinosaur,
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which gives them superb low-light vision.
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And they're able to move
through the forest in near silence,
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thanks to cushioned pads on their feet.
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A group of edmontosaurs.
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They lack armor,
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but they're as big as T. rex
and twice as fast.
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To catch one needs cunning.
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Each of the hunters
carefully moves into position.
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Then one deliberately makes a noise.
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The edmontosaurs are alarmed.
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They now know hunters are close,
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but they don't know exactly
where they are.
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Time to spring the trap.
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One T. Rex rushes out.
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The herd panics and bolts to where
the other T. Rex is waiting in ambush.
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A perfectly executed plan...
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by one of the greatest land predators
that have ever lived...
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in the swamps of our prehistoric planet.
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This is the skull of a pachycephalosaur,
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a 16-foot-long plant eater.
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Despite years of research,
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we're still trying to understand
why it had this bizarre-shaped head.
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{\an8}The most distinctive feature
about the pachycephalosaurs, of course,
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{\an8}is this really weird dome
that they have on their head.
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All around it is a series of very odd
tubercles and nobbles and bobbles.
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They look quite dragonlike.
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{\an8}When they first saw
these very thick, domed skulls,
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{\an8}and these domes could be
up to 30 centimeters in thickness,
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they were thought to be very strong.
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It was thought that maybe they were
using them for headbutting each other
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in contests over social hierarchy.
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Today, animals
like bighorn sheep butt heads in this way.
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A thickened skull helps protect
their brain from impact.
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But does this fully explain
pachycephalosaur's domed head?
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A number of paleontologists thought
that they should look inside the skulls.
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They sliced up a number
of pachycephalosaur domes,
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and when they did that, they found out
that maybe it wasn't strong enough
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to withstand these direct head-on impacts.
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However, they did discover something else,
suggesting the dome had a different use.
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The surface was marked
with a mesh of tiny fibers.
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Perhaps they supported
brightly colored skin,
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used to attract a mate.
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This new theory seemed to be accepted
until 2013,
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when a new discovery was made.
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A pachycephalosaur was found,
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with marks showing it had survived
multiple injuries to the top of its head,
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and it wasn't a one-off.
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They went back and looked through
historic museum collections
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and discovered that actually there was
quite a lot of evidence for these lesions
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in a similar place across a whole bunch
of different pachycephalosaurs.
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This is good evidence
that they probably were headbutting.
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So, were the skulls strong enough
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to protect pachycephalosaur's brain
after all?
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To find out, scientists turned
to the latest scanning technology.
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We can use CT scans to build
virtual models of the bones,
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and then we can subject those
to various engineering tests
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in the same way that we'd do with
an aeroplane part or an artificial hip.
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This provided the final piece of evidence.
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What they've shown
is that pachycephalosaur domes
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could actually have withstood
an enormous amount of force.
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It's the sort of force
that goes through American footballers
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when they hit each other.
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We now believe
pachycephalosaurs used their head
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both as a formidable weapon...
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and as a colorful display.
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Two ways to demonstrate
who was boss in their prehistoric world.