This little mammal is a scavenger
Called Didelphodon, she is a marsupial
and specialises in raiding abandoned dinosaur nests
This evening, she could be in luck
Unfortunately, the smell of the nest blinds her senses to danger
(Squeaking)
(Huge roar)
(Bellows)
The end of the Cretaceous
The continents are taking their modern forms
But this movement of the Earth's crust
has produced a surge in volcanic activity
Massive eruptions that have lasted for centuries
have laid waste to landscapes,
filling the atmosphere with gases and debris
This desolate world is still ruled by dinosaurs,
as it has been for 160 million years,
but they are nearing the end of their reign
Life on earth is choking to death
Yet in the last two million years,
the dinosaurs' most infamous predator has appeared
Tyrannosaurus, a five-tonne, 13-metre long carnivore,
specifically evolved to kill other giant dinosaurs
This is a male
He's been drawn to this volcano by the smell of food
The area is full of geothermal springs
and the air thick with sulphurous fumes
But there is another smell here
In one smallvalley, there is the stench of death
Unwittingly, the Tyrannosaurus has been drawn into a natural trap
Volcanic vents are producing poisonous carbon monoxide,
and because it is heavier than air,
it has formed a suffocating layer close to the ground
The giant predator stands above the layer,
but as he puts his head down to feed
he begins to feel the effects
If he topples over now, he will never get up
Eventually, his sheer size is his salvation
As he stands up with his prize, his head just clears the gas layer
There are still islands of greenery between the lava flows
In the warm, moist climate of the late Cretaceous,
the vegetation has transformed
Instead of conifers,
broad-leaved trees fill the forest canopy
Driving this quiet revolution among the plants
is the remarkable evolution of flowers
Their secret lies in their intimate relationship with insects,
so close that some flowers can only be pollinated by insects
and some insects, like butterflies, can only feed on flowers
Among these new plants, the birds are flourishing,
and their calls form an ever-present chorus
Millions of years of evolution
have also created intimate relationships
among different types of dinosaurs
Especially the delicate balance between predator and prey
(Terrifying squawk)
(Hissing roar)
One dinosaur that specialises in defence
is the extraordinary Ankylosaurus
They are evolved to withstand attack even from giant predators
like Tyrannosaurus
At seven tonnes, Ankylosaurus are so heavily armoured
that even their eyelids are hardened
And if that wasn't enough, they have a formidable club
on the end of their tails
Sadly, not even these magnificent creatures have any defence
against the natural forces that are suffocating their world
Nearby lies the Tyrannosaurus nest
These are usually closely guarded by the mother,
but this nest has been abandoned,
and a Didelphodon has burrowed into the side
Dinosaurs are vulnerable because they lay their eggs on the ground
But size helps,
and the egg is a challenge for this marsupial
Soon the age of the mammals will dawn,
and they will grow massive,
but this is as big as Cretaceous mammals get
The Tyrannosaurus embryo inside the abandoned egg is already dead
The scent is a lure to another Didelphodon
(Snarls and growls)
(Growling)
(Loud shrieks)
Many dinosaur embryos cannot survive in this volcanic environment
because acidic pollution
prevents their eggshells from forming properly
(Bellowing)
The mother is calling for a new mate
Tyrannosaurus have huge territories of hundreds of square kilometres
Her challenge is to attract a wandering male
She may have to call like this for weeks
One of the Tyrannosaurus's principal sources of prey
are these bulky Torosaurus
In the late Cretaceous, herds of horned herbivores are very common
and attract many predators
It is rutting season To display, males flush blood into their crests,
creating vivid patterns
These displays help to avoid physical contact
With one-metre-long horns,
fighting can easily result in bad injuries
The best and the brightest crest
is all that is needed to settle arguments
Occasionally, showing off is not enough
and males resort to brute force
For this old Torosaurus, this was one fight too many
He will never again challenge for the right to mate
(Gruff mooing)
The mating call of the Tyrannosaurus
continues to echo across the volcanic slopes
And it has been heard
A male has killed a young Triceratops
It's not just to satisfy his hunger It is a gift
Female Tyrannosaurus are larger and more aggressive,
and he courts her with food
to stop her attacking him on sight
(Hisses)
(Growls)
The female arrives
(Short roars)
She is wary
The primary weapon of a Tyrannosaurus is its mouth
Its arms are tiny so it can carry a massive jaw
and remain balanced
This jaw can crush bone and tear off up to 70 kg of meat
with one bite
The male keeps his distance
Later that evening, they mate
This is the first of many couplings
as the male stays by the female while she is receptive -
ready to see off any other males
On the lava flows, a group of Anatotitan
wanders between islands of greenery
These animals are members of the hadrosaur family,
the most common group of dinosaurs in the Late Cretaceous
But their kind has evolved
to thrive in lush lowland swamps, not in an ash wilderness
Three days have passed
The Triceratops carcass has been stripped
and the female Tyrannosaurus is beginning to tire of her mate
(Roars)
(Hisses)
The male knows better than to stay
Gliding in from the coast,
a magnificent pterosaur, Quetzalcoatlus, is hunting for food
This is now a rare sight
For 20 million years, these flying reptiles have been in decline
These 13-metre giants are the only ones left
And this is a dangerous place to be
One-tonne crocodiles live in the lake,
and could easily drag the delicate glider to his death
Driven on to extinction
The skies of the future belong to the birds
that already flourish around him
Months have passed, and the female Tyrannosaurus
has built a new nest, camouflaged in the forest
Mother keeps watch
For the full two months of the eggs' incubation,
she will not leave or even eat
She knows her nest is a magnet to scavengers
Like this Dromaeosaur
His cautious approach is watched by the Tyrannosaurus
She judges exactly when he has got too close
(Roars)
(Squeals)
As the sun sets, another threat comes out to haunt the mother
(Chirps and yowls)
(Growls)
(Bellowing roar)
With food becoming scarce, the mammals are getting bolder
She checks to make sure more have not burrowed in,
then returns to her vigil
The weeks pass, and above the brilliant volcanic sunsets,
there are signs of an even more destructive natural disaster
Showers of shooting stars herald the approach of a giant comet
on a collision course with the Earth
Far below, the dinosaurs are oblivious
The Torosaurus herd continues to feed
Nervous of moonlight predators,
younger animals seek protection among the larger adults
(Restless mooing)
Using the darkness, a pair of Dromaeosaurs unsettle the herd
and isolate one of the youngsters
(Hoarse shrieks)
(Lowing noises)
(Shrieking)
Safe But the predators have tasted blood and will not give up easily
Morning reveals the results of last night's tussle
The little Torosaurus lost his fight with the predators
For the herd, it is a blow Too few young are being born
in this polluted environment
A Didelphodon is already at the carcass
These little opportunists are about the only animals that are thriving
During their reign, dinosaurs have adapted to huge changes
but now they face a combination of events
that will spell their doom
After trekking across the ash fields,
Anatotitans gather round a stagnant pool to drink and feed
Huge batteries of chewing teeth
make short work of the vegetation
Once again, the predators make the water's edge a dangerous place
The group senses danger and starts to break up
The mother Tyrannosaurus has broken her fast
and is back with a vengeance
Nearby is the reason for her hunger Three Tyrannosaurus chicks
The only survivors from a clutch of twelve
The moment they hear the kill,
they start calling for food
(Mewling and yelping)
The mother delivers a slab of Anatotitan meat
Only four weeks old and less than a metre high,
competition is intense between them
One is already picked on by the others
(Faint mews)
They'll remain under their mother's protection for another two months
Soon after that, she will abandon them,
or worse, view them as food
It is unlikely the outcast will last that long
A few days later and the mother rests
in the warm afternoon sun
There is no sign of the smaller runt
He may have been killed by his siblings
Increasingly, the bickering pair are happy to wander from their mother
to explore their surroundings
(Squawks)
From the undergrowth, a snake watches
These reptiles have only recently evolved
from the same family as lizards,
but they specialise in hunting warm-blooded creatures like mammals
They use sensory pits on their snouts
as a way of detecting the heat signatures of other animals
It doesn't like what it sees
(Hissing)
While the chicks play, they are oblivious to approaching danger
(Hoarse grunting)
The mother is caught completely by surprise
The Ankylosaurus has very little brain inside its reinforced skull,
so when faced with danger, it reacts automatically and aggressively
Normally, Tyrannosaurus would retreat,
but she will not abandon her young
(Low grunting)
(Roar)
The blow has cracked the mother's femur
and ruptured internal organs
She limps away in agony
(Chicks squawk)
That night, the usual evening chorus
is joined by the whimper of a dying giant
By morning, she lies lifeless on the baking ash fields
The chicks stand expectantly by the colossal corpse of their mother
Hours pass, and still they wait
But their fate will now be settled,
along with all the other giant dinosaurs of the Cretaceous
3,000 km to the south, the massive comet crashes into Earth
(Dinosaurs squawking)
The light from the impact fades in silence
Then the shock waves arrive
(Rumbling)
Next comes the blast front
(Winds howl)
(Tearing and crashing)
Finally a rain of molten rock starts to fall out of the darkening sky -
this is the end of the age of the dinosaurs
The comet struck the Gulf of Mexico
with the force of 10 billion Hiroshima bombs
In the catastrophic climate changes that followed,
65% of life died out
It took millions of years for Earth to recover,
and when it did, the giant dinosaurs were gone,
never to return
In their place have emerged other powerful and beautiful creatures
We now know one small group of dinosaurs
did survive the extinction -
and they are all around us today -
the birds