Surely one of the most remarkable animals that had ever existed,
and certainly one of the most famous, is a dinosaur.
Tyrannosaurus rex.
An animal to spark the imagination for all of us.
What kind of an animal was it?
What did it look like? How did it live?
Now, scientific research has answered such questions.
And not just about T. rex,
but the other species that lived alongside it.
And the latest imaging technology enables us to bring them all to life.
Planet Earth, 66 million years ago.
The skies are filled with flying giants.
In the seas, monstrous reptiles patrol the depths.
And on land, dinosaurs of every kind,
all facing the struggle to survive.
We now know so much about a world that was ruled by the dinosaurs.
This is their story.
The southern shores of the great inland sea
that splits North America.
And the tracks of the land's top predator.
A Tyrannosaurus rex taking a swim.
Hollow, air-filled bones and powerful hind limbs
make T. rex very effective swimmers.
This is an adult male with his young family.
His offspring are now just old enough to follow him on a journey
to one of the many offshore islands that fringe this coast.
It's a short enough crossing, but it can still be a dangerous one.
A mosasaur.
A giant marine lizard over twice the size of a tyrannosaur
and weighing over 15 tons.
It's the largest predator on the planet.
Turtles are normally on a mosasaur's menu.
But this brood would make a welcome snack.
An adult T. rex, even in water,
could still defend itself very effectively.
But the young must stay close.
Tyrannosaurus rex often lose at least two-thirds
of their original brood of 15 or so in the first year.
Now there are only four.
The island offers safety and the promise of food.
Giant two-ton turtles are here to nest.
But this is the one that has drawn him here.
It's dead, and the tyrannosaur has smelled its rotting body.
If he can just get to the underbelly,
he will have over 2,000 pounds of easy meat.
T. rex has the most powerful jaws in nature.
And can bite with the force of over five tons.
The young are keen for a taste, but he's not sharing it.
It's time for them to learn to hunt for themselves.
The beach, however, doesn't look very promising.
But as the evening approaches, things start to change.
Baby turtles are beginning to hatch from the sand and rush down to the sea.
The young T. rex have been brought to an ideal training ground.
Hatchling turtles are the perfect size for a novice to tackle.
It pays for any hunter to be inquisitive.
There's a lot to learn.
And there's enough food here to satisfy both parent and young.
And if all else fails,
you can always steal supper from someone else.
Across the globe,
these shallow coastal seas cover an area of 25 million square miles.
Far more than even the largest continent.
That, combined with the richness of the waters,
makes them very important habitat.
Wherever land meets sea,
nutrients rise from the deep, fueling an abundance of life.
It's especially rich here in the North Atlantic,
where huge shoals of fish come close to the shore.
One kind of animal thrives in such places and forms immense colonies.
Flying reptiles. Pterosaurs.
Here, on the beaches of North Africa, there are seven different species of them.
They come here to feed, to rest, and to raise their young.
Tethydraco are well-adapted to spend time on the ground
and not only make their nests here but stay to protect their brood.
And their young certainly need protection.
The dagger beak of Phosphatodraco.
A nine-foot-tall predator that stalks through these colonies,
looking for a chance to snatch an unguarded hatchling.
But some types of pterosaurs are less well-adapted to life on land.
They have a slightly different nesting strategy.
They make their nests where they will attract less attention from predators.
Isolated cliffs like this are ideal.
Pterosaur eggs are leathery and can easily dry out,
so they need to be covered.
Beneath this pile of seaweed, something is stirring.
A tiny Alcione hatchling, just a few inches high
and weighing less than two ounces.
Their mothers left the eggs here about two months ago.
Calling to each other synchronizes hatching.
There is safety in numbers.
Their first instinct is to climb.
Hatchlings from hundreds of nests gather on the cliff-top
to prepare for their first flight.
But their wings are still unformed.
The bones of the long finger that supports their wing membrane
must first straighten and lock together, and that will take some hours.
But they can't stay here for long.
Their bones are extremely light, up to 90% air,
and that makes the effort needed to take off much easier.
Even so, test flights are essential.
There will only be one chance to get it right
when the time comes to launch.
The cliff edge creates updrafts, and they can help.
So, it pays to gather there facing into the prevailing winds
and towards the mainland.
But no one seems quite ready to take the plunge.
Until, at last, one youngster sets them all on their way.
They're not heading for the beach and its colony.
They need to get to the mist forest that lies beyond.
Barbaridactylus.
Powerful, predatory pterosaurs that normally catch fish.
But the hatchlings are too good to miss.
One way to take evasive action is to simply fold their wings and drop.
But losing height will make it harder for them to reach the forests.
A crash landing in the colony.
It's no place for a hatchling on its own.
A lucky survivor from the first wave of hatchlings…
still heading in the right direction.
Sanctuary.
Of the hatchlings that left the stack, few get as far as this.
But for them,
this forest offers all the shelter and food that a young pterosaur needs.
For the next five years, this will be their home.
Then, they will be large enough to join the adults,
catching fish out on the open ocean.
Some marine animals that spend all their lives fishing out at sea
must occasionally visit the coast for a very particular purpose.
In the waters off the drowned continent of Zealandia,
a long journey is coming to an end.
These are tuarangisaurs,
a type of huge marine reptile nearly 30 feet long.
This female is accompanied by her calf, about six months old.
At most, she'll have only one youngster every two years or so.
It's a huge investment,
and one that makes the bond between mother and young very important.
She has brought her young calf many miles to this one bay.
And they're not alone.
Tuarangisaurs come here from across the South Pacific.
Males also gather here to display to females.
But for now, courtship is not the female's first priority.
This bay has something that few others can provide.
Pebbles that are particularly smooth, hard, and rounded.
They've been worn by the action of river water, but they're hard to find.
Here, however, in the pool at the bottom of a waterfall,
there are plenty of them.
And the tuarangisaurs can take their pick.
They then do something rather remarkable.
They swallow them.
They need the stones to act both as ballast and as gizzard stones.
Gastroliths which will remain in their stomachs
to grind up their unchewed food.
For a youngster,
learning to swallow pebbles for the first time isn't easy.
It takes a little practice.
But it's also a chance for his mother to find a suitable mate amongst the males.
For the calf, at last, success.
Now, he will swallow as many as he can.
And, as he grows, he'll return here for more.
It's time for the family to leave the coast
and head back out to sea to feed.
And for the young tuarangisaur,
that is an important step on the road to adulthood.
In southern Europe,
where the Atlantic meets the great Tethys Sea,
coastal life reaches perhaps its greatest diversity.
Rising sea level means that there are countless submerged islands
covered with sponges, clams and corals.
Corals take advantage of the sunshine in these shallows,
forming partnerships with algae that grow within their tissues.
They collect tiny particles of food floating in the ocean currents.
Myriads of these marine creatures encrust the solid rock.
But one rock here appears surprisingly bare.
Beyond is a sheer drop-off and the deep sea,
home to oceanic predators…
and danger for unwary reef fish.
But this pycnodont fish has little to fear.
This is Hoffman's mosasaur, the ocean's deadliest predator.
But he's not here to eat. He's come to be cleaned.
Mosasaurs are giant lizards and have both a lizard's forked tongue,
and during the mating season, a lizard's colorful skin.
Now it's time to shed old skin.
And when you need to look your best,
nothing but an all-over body scrub will do.
Fish and shrimp pick scales shed from his body.
Resting at the surface allows this sea-going, air-breathing lizard
to fill his lungs,
and relax.
A rival.
A younger male, challenging for this territory.
The old male is heavier, over 15 tons.
But his rival is more nimble.
When they are as evenly matched as this, these battles can be lethal.
Mosasaurs have been found with the shattered teeth of rivals
embedded in their skulls.
The old male snatches a breath.
Now he has the advantage.
By dragging his rival down, he could drown him.
The old male has triumphed.
For now, at least, this reef is still his territory.
A crescent moon off the coast of North America.
The calm, dark nights that follow trigger a rare and beautiful event.
Tonight, even in the deep, there is light.
Glowing ammonites rise from the abyss.
Ammonites are mollusks, related to octopus and squid.
These scaphitids are no bigger than a human hand.
For weeks, they've been gathering in the coastal depths.
In the deep, these lights may help lure plankton as food.
But tonight, they serve a different purpose.
They've been drawn to the surface to mate.
And soon there are thousands in each shoal.
Neighbor triggers neighbor, creating waves of bioluminescence.
They have complex nervous systems,
controlling light-producing cells called photocytes.
The males jostle for a place around the larger females.
Clues from their displays tell her who is the fittest and who is the best mate.
As couples entwine, they coordinate their light displays.
If he can't match her precise rhythm, he'll be rejected.
But there is perfect synchrony.
This pair will now spawn and help produce the next generation.
After fertilization,
the females enter the shallows to release their eggs.
As with most cephalopods,
breeding is the final act of their short lives.
By morning, these lights will have flickered and died.
This magical night will be their last.
All over the globe, the coast provides an ideal place
for countless animals to mate, raise their young, and to feed.
Back in the shallow waters of Zealandia,
large groups of tuarangisaurs have come together.
They propel themselves with all four fins and travel almost effortlessly
to find the fish shoals that gather here in summer.
Occasionally, they break the surface to gulp air
before continuing on their underwater flight.
But one female is not swimming with her usual grace.
She and her two-year-old calf are lagging behind the rest of the group.
She's moving rather laboriously.
And that has not gone unnoticed.
A deadly hunter, Kaikaifilu.
The apparently stricken female is a tempting target.
Diving to deeper water might make her less vulnerable.
For the calf, trying to distract the mosasaur is a dangerous game.
But it's buying time.
The mother and calf are not entirely alone.
These individuals may be related,
and it's in all their interests to drive Kaikaifilu away.
This is the reason for the female's apparent distress.
She's pregnant.
And now, after a one-and-a-half year pregnancy,
a baby.
Over ten feet long, nearly half the length of its mother.
One of the biggest babies of all time.
It needs to get to the surface to take its very first breath.
This young tuarangisaur could live for 80 years.
Now, supported by her family,
she can take her place as a predator…
in one of the richest habitats on Earth,
the seas around the coasts of our prehistoric planet.
Next on Prehistoric Planet,
giant dinosaurs wrestle to win a mate in baking-hot deserts.
And across the globe,
remarkable specialists must use every trick they can to survive
in the most inhospitable places on Earth.
To discover the science behind the stories,
go now to the Prehistoric Planet show page.