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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 mouth of a river in southern Europe
66 million years ago.

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In the aftermath of a tropical storm,
debris is drifting downstream.

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And amongst the wreckage,
rafts of vegetation ripped from the land.

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For a weary pterosaur, this one may be
a welcome place to rest...

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but it's far from safe.

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A huge mosasaur,
a deadly underwater hunter,

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is looking for an easy meal.

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Such as this little dinosaur, Zalmoxes.

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Staying here is too risky.

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He needs a larger raft, and quickly.

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There's little choice but to swim for it.

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He is not the first here.

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Another castaway.

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A female.

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Their raft is drifting out to sea.

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Sometimes, castaways on rafts like these

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are washed up on the shores
of the distant islands.

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If they're very lucky,
this pair could become pioneers.

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And may establish a new population,
which eventually becomes a new species...

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unlike anything seen before.

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The longer an island has been isolated,

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the more different its animal inhabitants
may become.

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These small islands in southern Europe

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are home to a strange,
rather shy hadrosaur.

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Feeding amongst these pine saplings, Tethyshadros.

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Just a quarter of the size
of its giant cousins on the mainland,

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it stands no taller than a human being.

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With its unique serrated bill,
it can forage among the tough vegetation.

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Hunters like T. rex have never reached
this little island,

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so it should be a safe place
for a mother to raise her brood.

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But not necessarily.

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Hatzegopteryx.

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Giant predatory pterosaurs.

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The best chance of escape
is beneath the canopy of the taller trees.

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These small calves have been left behind
among the saplings.

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Mother and young are separated.

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Hatzegopteryx
are very intelligent pterosaurs.

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Now that the element of surprise has gone,
they change tactics.

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Spreading out across the clearing,

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they try to flush out any prey
that might still be there.

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The youngsters' best hope
is to stay completely still...

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and not to run.

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These two are lucky
to be back with their mother.

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The island-hopping pterosaurs move on
to try their luck elsewhere.

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The hadrosaurs can return to feeding.

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The island of Madagascar
has been separated

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from the African mainland
for 80 million years.

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So long that most of its animals
are now very different

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from any to be found elsewhere.

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This is Simosuchus.

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It's not a dinosaur
but a miniature relative of crocodiles.

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One that lives almost entirely on land

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and is strictly vegetarian.

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Simosuchus have tough, armored bodies
which protect them from attack

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by the island's predators.

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So they can risk dropping their guard...

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sometimes.

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Majungasaurus, Madagascar's top hunter.

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This particular female
is blind in one eye,

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so she finds it hard to make a kill,
and she's now very hungry.

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The Simosuchus have a network
of escape routes

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that lead them
to their underground burrows.

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Once inside, they block the entrance
with their heavily armored backs.

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This little male is unlucky.

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But he's not helpless.

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Reverse charges,
tail swipes and aggressive kicks.

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The hunter's snout is too broad
to reach very far inside.

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But just to be on the safe side,
the Simosuchus digs even deeper.

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For the Majungasaurus,
yet another hunt has ended in failure.

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Simosuchus is not the only evolutionary
oddity to thrive on Madagascar.

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The island is also home to another group
of very unusual animals.

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Mammals.

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This is a female Adalatherium.

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She's less than two feet long.

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But even so, she's still one of
the largest mammals to have yet evolved.

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She spends most of her waking hours
searching for food.

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At the end of this tunnel, there are eggs...

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potentially a rich source of protein.

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But she doesn't eat
this particular clutch.

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These are her own eggs.

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And this is her burrow.

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The eggs are starting to hatch.

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The hatchlings' eyes have not yet opened,

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but instinctively, they head
towards their mother to feed on milk.

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She produces it
from modified sweat glands on her belly,

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and for now, it's all the food they need.

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Two months later, and the cubs
have more than quadrupled in size.

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To produce enough milk for them,

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their mother must herself
eat a great deal.

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So every night, she has to leave
the safety of the den in order to feed.

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Her eyesight,
like that of many burrowing animals,

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is not very sensitive.

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She relies instead on her acute hearing.

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And if she hears something
that might be dangerous,

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she stays perfectly still.

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Trouble avoided.

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She returns to searching
in the earth for roots and seeds.

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The cubs are growing fast
and so are their appetites.

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The female is now having to search
almost nonstop for food.

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So her cubs are left unguarded
for hours at a time.

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Masiakasaurus.

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A hunter.

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And one particularly well-adapted
for catching burrowing prey.

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With its long neck and narrow head,

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it can investigate any hole
that might contain a meal.

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But hunters may themselves
become the hunted.

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Madtsoia, a snake nearly 25 feet long,
squeezes its prey to death.

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This neighborhood
has now become rather dangerous.

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As night falls, the mother leads her young
out of the burrow for the very first time.

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For now, at least,
they must stay close together.

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In the far south of the planet,
on the islands of the Antarctic Peninsula,

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winter brings
months of freezing temperatures.

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Here, too,
being part of a family brings benefits.

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A thermal camera
reveals a huddle of glowing bodies.

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Imperobator.

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Hunters.

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Like most dinosaurs,
they are warm-blooded.

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But to stay warm, they need a lot of food.

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So they must make a kill
every few days if they can.

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Fresh snow muffles
the sound of their footsteps,

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enabling them to move undetected
through the forest in search of prey.

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A Morrosaurus.

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A plant eater for whom winter
is inevitably a very hard time.

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Imperobators specialize
in hunting such prey.

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The Morrosaurus
is faster than its pursuers.

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But it's outnumbered by the pack.

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The Imperobators' long-feathered tails
give them remarkable maneuverability.

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The chase has reached
the very edge of the forest.

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Beyond lies a frozen lake,
half a mile wide.

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The clear, open space could give
the faster Morrosaurus an advantage.

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But the frozen surface is treacherous.

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With the Imperobator closing in,
it isn't much of a choice.

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A misplaced step.

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A chance for the Morrosaurus
to sprint beyond the predators' reach.

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But this is an island,

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so hunters and hunted
will almost certainly meet again.

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Some islands are so small

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that they have
no large land-living residents.

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But they may, nonetheless, get visitors.

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Hatzegopteryx.

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This male has arrived
carrying a 40-pound Tethyshadros carcass.

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A prize from a recent hunt.

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He is 15 feet tall,
with a wingspan of over 30 feet.

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Hatzegopteryx are Europe's top predators.

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But this male has come here to reveal
another side to his character.

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He has constructed a display to make it
clear to any females passing overhead

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that he is looking for a mate.

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But he might have a very long wait
before he gets a response.

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At last. A female.

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She seems interested,

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but a little more persuasion
might be necessary.

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And he needs to be careful.

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One well-aimed peck from her beak

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could quickly bring
his whole mating season to an end.

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His display must demonstrate
that he has the good genes

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that her young would do well to inherit.

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The dead dinosaur suggests
that he's a good hunter

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and carrying it here
has proved that he's a strong flyer.

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But if she is impressed,
she isn't showing it yet.

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Time to produce
some new evidence of his eligibility.

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Head lifts invite her to come closer.

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Now, she gives him a little encouragement.

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A synchronized dance
creates trust between them.

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Another male.

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He's much younger,
but he could still be a rival.

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That's him dealt with.

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Disaster. The female has left.

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He may have lost his chance.

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She's back.

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Seeing off a potential rival
might even be another point in his favor.

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He continues from where he left off.

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One last reminder of his strength.

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And this is his only contribution
to fatherhood.

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It's all over in just a few seconds.

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But it's the start of the next generation
of these giant flying hunters.

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Islands like this may only be small,

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but like countless others
around the world,

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they bear witness to crucial moments

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in the lives of some
of the most unusual creatures

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on the Prehistoric Planet.

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During the time of the dinosaurs,

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the skies were dominated
by flying reptiles called pterosaurs.

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There were over 250 species...

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and some of them were enormous.

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One of the most interesting,
because they're the most bizarre,

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{\an8}are the azhdarchid pterosaurs.

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{\an8}And to try and describe

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{\an8}what an azhdarchid pterosaur is like
is very difficult.

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They stand as tall as giraffes.

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They've got heads
that may have been two meters long,

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wingspans of ten meters.

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They're some of the most bizarre things
who've ever evolved on Earth.

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Despite their size,
these giants were well-adapted for flight.

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So why do we think
they hunted on the ground?

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{\an8}The azhdarchid's wing is a skin membrane

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{\an8}supported entirely
by a superenlarged fourth finger.

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{\an8}This skin membrane extended
from the tip of that giant fourth finger

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{\an8}all the way to the top of the hind leg.

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Azhdarchids were supremely adapted
for covering great distance,

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but they weren't the kind of animals
that were twisting and turning

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and making agile movements
actually in flight.

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This would've made it hard for azhdarchids

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to catch other flying animals.

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They must have
had a different way to hunt.

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One of the most prevalent ideas about how
azhdarchid pterosaurs may have fed

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is by using this bizarre mechanism
of foraging known as skim feeding.

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Today, birds
like black skimmers feed in this way.

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It's the most ridiculous way
of getting your food you can imagine.

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It's literally pushing your lower jaw
through the water

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and crashing into your food.

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A skimmer's neck
is built to absorb sudden impacts.

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But fossils reveal azhdarchids
had none of these adaptations.

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In fact, they would almost certainly
break their necks from just the strain

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of trying to push their lower jaws
through the water.

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An azhdarchid had no option.

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It must have landed to find food.

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But could it really walk
fast enough to hunt?

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Scientists needed evidence
to persuade them

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00:36:54,423 --> 00:36:57,551
that they could do anything more
than just waddle.

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That evidence comes
from 66-million-year-old footprints.

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The biggest pterosaur track
in the world was made

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by a walking giant azhdarchid.

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That's not only a cool thing to have,

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it tells us an awful lot
about how efficient they were at walking.

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These tracks show

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they held their limbs
directly under their body,

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giving them an upright stance.

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00:37:28,749 --> 00:37:30,250
Their feet were padded.

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And unlike the small pterosaurs,

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their long legs
gave them an enormous stride.

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Although azhdarchids
are peculiar-looking animals,

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they're moving very efficiently.

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00:37:49,102 --> 00:37:53,315
Azhdarchids combined
this competent terrestrial walking ability

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with this massive long stork-like face.

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00:37:56,693 --> 00:37:59,071
They almost certainly were predators

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that walked around reaching down
to grab animals.

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00:38:07,412 --> 00:38:08,830
We have to remember, though,

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the throat size of this thing
is half a meter wide.

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That's about the width of my shoulders.

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We would be on the menu for these things
if they were alive today.

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Pterosaurs would have been
an awe-inspiring sight in the sky.

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00:38:31,228 --> 00:38:36,275
But these giants were even more impressive
and terrifying on the ground.