Imagine you could travel back in time - to a time long before man
Back across 65 million years
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
You've reached a 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
(Fierce roar)
Giant reptiles like Tyrannosaurus, a five-tonne predator,
stalk the land
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
To the Jurassic period - when life on Earth
was at its most spectacular
(Low grumbling roar)
The creatures here bathe in a warm tropical climate -
there are no icecaps at the poles
Flowers and broad-leaved 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
There are no separate continents,
just one landmass 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,
an evolutionary battle has broken out among the newer types of reptile
for supremacy of this strange world
On these Triassic proving grounds, dinosaurs are still rare,
but they are beginning to show signs of their future success
(Small growl)
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 Coelophysis can survive on very little water
She is also light-boned, fast, and she is beautifully adapted
for killing
Dinosaurs appeared around 10 million years before,
as small predators
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
(Loud roar)
(Trumpeting calls)
A chorus of calls signals the arrival of a huge herd of Placerias
They are making their way down from the ferns for their morning drink
These impressive one-tonne beasts are not related to dinosaurs
They are a much more ancient type of reptile
Once there were many different kinds of these powerful creatures,
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
(Angry growling)
But on two angry males, these tusks can make lethal weapons
For the swift Coelophysis, Placerias are prey
This young female targets the old and weak
in the slow-moving herd
(Growling and trumpeting)
One day, the descendants of dinosaurs like Coelophysis
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 cynodont is a missing link between reptiles and mammals
As he runs, his backbone moves
from side to side like a reptile's,
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 cynodonts is very strong -
they pair for life
Like all land reptiles, they lay eggs,
but after hatching, the young are utterly dependent on their parents
and for the first three months,
feed from milk glands on the mother
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 herd spreads out over the scrubland to feed
(Low growling)
Suddenly the warm breeze changes
and there is the scent of fear in the air
(Vicious growling)
Postosuchus, a merciless ambush predator -
the largest carnivore on Earth
(Roars)
The terrified Placerias flee, but they are desperately slow
and one of them is mortally wounded
Their tormentor is a distant cousin of the dinosaurs,
but unlike them, she is too front-heavy to run on two legs
Yet the Postosuchus is easily fast enough to keep pace with the herd
Eventually, 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 Postosuchus 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 like this Peteinosaurus
She is a flying reptile who has evolved extra-long fingers
to support her delicate wing membranes
(Rattling call)
The river's resident flying predators are dragonflies
Insects like these evolved long before the first reptiles
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
Peteinosaurus 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
In temperatures of over 40 degrees centigrade,
the Placerias need lots of water
and spend more time at the river
But the herd is nervous
They know this is a good place for an ambush
The Postosuchus is not hunting
She has recently eaten her fill
and also needs to come down to the river to drink
Six metres 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 Postosuchus
(Loud, rasping roar)
It is the middle of the dry season, months since any rain
Across the scrubland, smaller rivers are drying out
In one, a Peteinosaurus risks a cooling bath
He constantly checks for danger
The cynodonts lie secure and cool
through the hottest part of the day
But no animal here is truly safe
The female Coelophysis has picked up the scent of their bedding
Soon she is exploring the entrance
and she is not alone
(Puppy-like growling)
Clearly these dinosaurs have not met cynodonts before
Nearby, the Placerias search for moist roots
beneath the drying ferns
The Postosuchus 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 defence
(Angry roaring)
She will get no food here, and in such a competitive world,
her wound may yet prove fatal
Evening, and in the burrow,
the cynodonts prepare for a night of hunting
The young are more developed now
and starting to move about the nest,
but they are stillvulnerable
It'll be 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
(Squealing)
(Cynodont barks)
Too late, the male responds to his squealing pup
Again, he drives the dinosaurs away,
but this time, they don't go far
Nearby, a thirsty male Postosuchus
has invaded the wounded female's 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 Coelophysis are starting to dig the cynodonts 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 cynodonts the chance of escape
Under the moonlight, they seize the moment and abandon the hole
In the morning, the Coelophysis are back
They can smell the cynodonts, and it will take them time
to realise their work is in vain
The dry season continues
After the cynodont hole,
the female Coelophysis has found something in the parched river bed
It is a lungfish, and the dinosaur's serrated teeth
will make short work of its protective cocoon
But she is not left alone to eat it for long
Coelophysis numbers are increasing,
and this leads to confrontations
(Vicious squealing)
The pressure of numbers also brings other changes in behaviour
Under the merciless sun,
a flock of Coelophysis 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's heavy armour and muscle
are no more than food for the agile little dinosaurs
Their long snouts and nibbling 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 by the shrunken river
Coelophysis are gathering in huge numbers,
and in years of hardship like this,
it is the dinosaurs that win through
There is little room for other reptiles, and without 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 cynodonts have survived their brush with death
and dug another burrow hidden in some dried ferns
Once again, the male is hunting in the darkness
(Growling, animal squeals)
He has caught the only common prey -
a baby Coelophysis
(Thunder rumbles)
After nine months of drought,
at last the rains have arrived
Soon, the thirsty scrublands are soaking
In her burrow, the female cynodont has laid a fresh clutch of eggs
One day in the 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'll 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 Coelophysis has survived the drought,
along with many of her kind
But they have also been joined by another type of dinosaur
(Low, rumbling call)
A huge herd of Plateosaurus
has been drawn to the swollen river
It is hard to believe that these beasts are related to Coelophysis,
but these are plant-eating dinosaurs
Their size is the key to their success,
and at four tonnes, they are simply too big to be threatened
This is the shape of things to come -
the age of the dinosaurs has dawned
20 million years later,
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 programme,
we meet the giants of the Jurassic