Imagine you could travel back in time to a time long before man, back across 65 million
years.
As you travel, you would see huge changes in the vegetation and the climate.
Even the surface of the Earth itself would move as mountain ranges are pushed up by colliding
continents.
Now you've reached a remarkable period in Earth's history known as the Cretaceous.
It is a very different world.
The Himalayas do not yet exist and the Atlantic is only half as wide.
There is no grass, only conifer forests and fern prairies.
This is a world ruled by dinosaurs.
As reptiles like Tyrannosaurus, a 5 ton predator, stalk the landscape.
In walking with dinosaurs, we will show you how these magnificent creatures live, how
they eat, fight and reproduce.
You will witness how the forces of nature conspire to drive these animals to extinction.
But this series will also take you back much further.
Back to the Jurassic period, a time when life on Earth was at its most spectacular.
The creatures here bathe in a warm tropical climate.
There are no ice caps at the poles.
Flowers and broadleaved trees are yet to evolve.
In the air and on the land, the world is dominated by reptiles and by far the most common are
the dinosaurs.
But they are not the only giants.
Huge pterosaurs rule the skies and below them, massive marine reptiles harvest the rich
oceans.
However, first this series will go back even further to discover where dinosaurs came from.
This is our own Earth during the Triassic period.
Here there are no separate continents, just one giant land mass called Pangaea.
It is a harsh place, dominated by deserts.
The Triassic has already seen many different varieties of ancient reptiles come and go,
but now out of this dry wilderness has appeared something revolutionary.
A family of reptiles destined to shape the course of life on Earth for the next 160 million
years.
These are the first dinosaurs and this is where our story begins.
First light across the western hills of Earth's only continent, Pangaea.
This world has been ruled by one group of giant reptiles for over 50 million years, but these
ancient creatures have had their day.
All over these lush fern prairies a grim evolutionary battle has broken out among the newer types
of reptile for supremacy of this strange world.
From these Triassic-proofing grounds, dinosaurs are still comparatively rare, but they are
beginning to show the first signs of their future success.
It is the end of the wet season and the local river is full, but it will not remain this
lush and ahead lies nine months with no rain.
One type of reptile has evolved to thrive in drought.
Dinosaurs like this celophysis can survive on very little water.
She is also light-boned, fast, and she is beautifully adapted for killing.
Dinosaures first appeared around 10 million years before as small predators, but what
makes them unique is special hips and ankles that allow them to stand perfectly balanced
on two legs.
With lightning-fast reactions, they are built to survive.
A growing chorus of calls signals the arrival of a huge herd of placerias.
They are making their way down from the fern scrubland for their morning drink.
These impressive one-ton beasts are not related to dinosaurs.
They are a much more ancient type of reptile.
Once there were many different varieties of these powerful creatures swaggering across
the landscape, but now the placerias are the only ones of their kind that remain.
They are an endangered species.
Despite their fearsome appearance, they are actually gentle herbivores.
Their tusks are used for digging up roots.
But on two angry males, these tusks can make lethal weapons.
For the swift celophysis, placerias are prey.
This young female targets the old and weak in the slow-moving herd.
One day, the descendants of dinosaurs like celophysis will take over this world, but
it is their speed and agility that gives them the edge in the mid-triassic.
Further downriver is one of the triassic's most bizarre animals.
The synodont is a missing link between reptiles and mammals.
As he runs, his backbone moves from side to side like a reptile, but he has hair and lives
down a burrow like a mammal.
Deep inside, his mate sleeps on a bed of lichen.
The bond between synodonts is extraordinarily strong.
They pair for life.
Like all land reptiles, they lay eggs, but after hatching, the young are utterly dependent
on their parents and spend their first three months feeding from special milk glands on
the mother's stomach.
This form of reproduction has evolved to protect their young from the daylight predators outside.
By day, even the father sticks close to the safety of the burrow and carries out domestic
chores, he only hunts at night.
In the not too distant future, small furry mammals will evolve from reptiles like these.
In the heat of the dry season, the placerias herds spreads out over the scrubland to feed.
Only the warm breeze changes, and there is the scent of fear in the air.
Poster sucus, a merciless ambush predator, the largest carnivore on earth.
The terrified placerias flee, but they are desperately slow, and one of them now carries
a mortal wound.
Their tormentor is a distant cousin of the dinosaurs, evolved from the same reptilian
ancestors, but unlike them, she is too front heavy to run on two legs, yet the poster sucus
is easily fast enough to keep pace with the herd.
Only a combination of shock and blood loss defeats the wounded placerias.
The carnivore's bite has done its job.
The placerias is now too weak to fight, and the poster sucus has an easy meal.
As the weeks of the dry season pass, only the vegetation around the river remains lush,
and this attracts exotic hunters from far and wide, like this patinosaurus.
She is a flying reptile who has evolved extra long fingers to support her delicate wing membranes.
The river's resident flying predators are dragonflies.
Insects like these evolved long before the first reptiles, and over 100 million years
ago, some took to the air and became aerial killers.
But in the Triassic era, these hunters have become the hunted.
A jaw full of needle-sharp teeth makes short work of the insect.
Patinosaurus have evolved strong, lightweight bones for flight, and like the dinosaurs,
they are fast and deadly.
Reptiles are becoming the new masters of the air.
When temperatures of over 40 degrees centigrade, the placerias need lots of water, and these
ancient reptiles have to spend more time at the river, but the herd is nervous.
They know this is a good place for an ambush.
The poster sucus is not hunting.
She has recently eaten her fill and also needs to come down to the river to drink.
Six meters long, heavily built with an armoured back, she needs a huge amount of food and
therefore has to defend a very large territory.
The only creature on the planet she fears is another poster sucus.
It is now the middle of the dry season and months since any rain.
Once the scrub lands, smaller rivers are drying out.
In one, a patinosaurus risks a cooling bath.
He constantly checks for danger.
The synodonts lie secure and cool through the hottest part of the day, but no animal here
is truly safe.
The female celophysis has picked up the scent of their bedding.
Soon she is exploring the entrance, and she is not alone.
Today these dinosaurs have not met synodonts before.
Nearby the placerias search for moist roots beneath the drying ferns.
The poster sucus once again needs food, but her last attack left her with a tusk wound
on her thigh, a severe handicap for such a heavily built creature.
The placerias herd spots her before she can set an ambush, and they mount an aggressive
defense.
She will get no food here, and in such a competitive world, her wound may yet prove fatal.
Evening and in the burrow, the synodonts prepare for a night of hunting.
The young are more developed now and starting to move about the nest, but they are still
vulnerable, and it will be another two months before they can do without their parents protection.
The adult male checks the coast is clear.
An inquisitive youngster follows him to the end of the burrow.
Too late the male responds to his squealing pup.
Once again he drives the dinosaurs away, but this time they don't go far.
Nearby a thirsty male poster sucus has invaded the wounded females territory, but this withered
triassic landscape cannot support two giant predators in one dry valley.
The female is too weak to fight.
After dominating her territory for a decade, she is driven from her home.
The male uses precious water to mark his new territory.
Meanwhile the sealophysis are starting to dig the synodonts out.
Their situation is becoming desperate, as the dinosaurs will soon expose the nest.
As the sun sets, the pair have only one choice.
It means shattering their unique parental bond.
They eat their own young.
This denies the dinosaurs their food and gives the synodonts the chance of escape.
For the moonlight, they seize the moment and abandon the hole.
In the morning the sealophysis are back, they can still smell the synodonts, and it will
take them some time to realize their work is in vain.
The dry season continues.
After her wasted effort at the synodont hole, the female sealophysis has found something
in the parts riverbed.
It is a lungfish, and the dinosaur's unique serrated teeth will make short work of its
protective cocoon, but she is not left alone to eat it for long.
The sealophysis numbers are on the increase, and this leads to confrontations.
The pressure of numbers also brings other changes in behavior.
Under the merciless sun, a flock of sealophysis has united for a kill.
The wounded female postosuchus has lost the use of her back legs, however her mighty jaws
could still tear a dinosaur apart.
The great carnivore's strength fails.
All the postosuchus' heavy armor and muscle are no more than food for the agile little
dinosaurs.
Their long snouts and nibbling front teeth can reach under her thick scales.
They eat her from the inside out.
The rains are late, and now the real test for survival begins.
As vast areas turn into red desert, the placerias are driven to migrate in search of water.
But in this extreme drought, dinosaurs have a crucial advantage over other reptiles.
When they excrete, they waste very little water.
Nowhere is this advantage more obvious than down by the shrunken river.
Sealophysis are gathering in huge numbers, and in years of hardship like this it is the
dinosaurs that win through.
There is little room for any other reptiles here, and without sufficient prey, the dinosaurs
swiftly turn on each other.
Cannibalism is common.
The triassic is pushing life to its limits.
Night reveals dinosaurs are not the only animals that have managed to cling on.
The synodonts have survived their brush with death and dug another burrow hidden in some
dried ferns.
Once again the male is hunting in the darkness.
He has caught the only common prey, a baby sealophysis.
After nine months of drought, at last the rains have arrived.
Soon the thirsty scrublands are soaking.
Inside her burrow, the female synodont has laid a fresh clutch of eggs.
One day in the distant future, this strategy of investing in their young will pay off for
their mammalian descendants.
But as mammals evolve over the next 160 million years, they will only survive as a few small
species, clinging on at the edge of a world dominated by dinosaurs.
Outside that future is already arriving.
The female sealophysis has survived the drought, along with many of her kind.
But they have also been joined by another type of dinosaur.
A huge herd of platiosaurus has been drawn to the swollen river.
It is hard to believe that these four-legged beasts are related to sealophysis, but these
are plant-eating dinosaurs.
Their size is the key to their success, and at four tons, they are simply too big to be
threatened.
This is the shape of things to come.
The age of the dinosaurs has dawned.
Twenty million years later, a massive extinction wiped out thousands of species of reptile,
but the dinosaurs went from strength to strength.
Carnivores grew to enormous sizes, but their prey got even bigger.
In the next program, we meet the giants of the Jurassic.
