[wind whistling]
[Morgan Freeman] 252 million years ago…
and our planet is dying.
[haunting music playing]
The biggest extinction event in history has left the world barren…
and deathly silent.
[music intensifies]
But this is the story of the few…
[snorts, panting]
…that survived.
[music fades]
[rousing music playing]
[snarling]
[trilling]
[screeching]
[rousing music continues]
[growling]
[wind howling]
[rumbling]
[rousing music intensifies]
[music fades]
The start of the Triassic Period…
and the rivers of fire are gradually subsiding.
In their wake,
cooling lava covers an area half the size of the United States…
[wind whistling]
…in a crust up to three kilometers deep.
[melancholic music playing]
Volcanic gases have caused global temperatures to soar.
Forests and reefs
have been annihilated.
Hundreds of millions of years of evolution,
gone.
Yet here,
hidden in the blackened landscape…
lies opportunity.
For there is one particular life-form that thrives on dead organic matter.
Fungi.
With the world an apocalyptic graveyard,
fungi were in their element.
And for a few thousand years…
these simple organisms
became the dominant life-form on Earth.
But not every survivor of the Permian extinction
relied on death for their success.
One lowly creature
found itself perfectly placed
to take over the world.
[purring]
[breathes gently]
[exhales]
Lystrosaurus…
[yawns]
…an ancient ancestor of the mammal.
This curious, pig-sized creature
was used to burrowing underground
and seeking refuge in caves,
a way of life that saved it
when other animals were dying.
[bellows]
Once hapless underdogs,
they are now one of the few lucky survivors of Armageddon.
With most vegetation destroyed by the extinction,
finding food is hard.
[snuffling]
But Lystrosaurus are resilient
and able to forage over large areas.
[stirring music playing]
They're constantly on the move,
searching for roots, tubers, and small pockets of regrowth.
[snuffling, grunting]
But they weren't the only animal survivors.
[sniffs]
[grunts]
Life in many forms
found a way.
[bellowing]
Lystrosaurus's simple but adaptable lifestyle
would reap astonishing rewards.
Facing little competition and no large predators,
the volcanic eruptions turned it from a bottom-of-the-food-chain burrower…
[snuffling, bellowing]
…to the animal that inherited the Earth.
[uplifting music playing]
In the years following the mass extinction,
they made up three-quarters of all vertebrate life on land,
something no other animal has ever done.
[bellowing]
But their dominance couldn't last,
for another survivor of the mass extinction
was on the ascent
thanks to huge changes to the very structure of our planet.
[music ends]
For tens of millions of years,
the Earth's continents had been converging,
creating a vast ocean on one side of the world…
and a single immense land mass on the other,
the supercontinent of Pangaea.
[intriguing music playing]
The drying that started in a previous era
is now compounded by searing heat.
[wind whistling]
Temperatures spike to 60 degrees Celsius.
Sandstorms scour the interior.
Dunes rise over a kilometer high…
gradually forming the largest and most hostile desert
the planet has ever seen.
[music fades]
Yet on the margins of this barren and lifeless landscape,
another group of survivors was on the rise.
And they still dominate our deserts today.
[pensive music playing]
This is the Atacama in South America.
It's been a desert here since the Triassic Period.
Some parts have gone decades without a drop of rain,
yet one type of animal thrives here.
Lizards.
They're reptiles, supremely adapted to this dry environment.
They have tough, scaly skin
so they don't shrivel in the baking sun.
Instead, the sun fuels them…
heating their cold blood so they can reach racing speeds.
But even desert reptiles need to quench their thirst.
Water seeping up through the ground.
Unfortunately, these water holes are almost as salty as the Dead Sea.
[flies buzz]
Drinking this would be a death sentence…
so these lizards get their water from an unexpected source,
an animal whose ancestors also survived Armageddon.
Insects were hit hard in the mass extinction,
but some made it through.
Today, these brine flies are salt specialists,
desalinating the water,
and in the process, making themselves into perfect little water bottles
for lizards.
[buzzing]
The challenge is catching them.
[playful music playing]
[buzzing]
Finally.
[buzzing]
But just when it thinks it's cracked it,
trouble on the horizon.
These prime fly-catching spots are in high demand…
[tense music playing]
…and the locals do not like to share.
[energetic music playing]
[music ends]
A stalemate,
but on another lizard's territory.
[energetic music resumes]
-[water splashing] -[music ends]
[buzzing]
[peaceful music playing]
[flies buzzing]
The thirsty lizard seizes the moment…
making the most of their distraction…
no matter how brief.
The ultimate desert dwellers,
lizards are tough and resilient,
just like their ancient ancestors.
But back in the Triassic, it was much larger reptiles
who would change the course of history.
In the four million years since the Permian extinction…
[grunts]
…Lystrosaurus have dominated.
They emerged into an almost empty world
and have been reaping the rewards.
[mewling]
Life is good.
[carefree music playing]
-[adult purrs] -[juvenile grunts]
[playful calling]
But these mammal ancestors
have had little competition or predators,
until now.
[growling]
[sinister music playing]
[growls]
With the planet recovering,
some reptiles have grown to epic proportions.
This is an Erythrosuchid.
[snarling]
Nearly three meters long, it's the biggest predator of its time.
[purring]
Herds of Lystrosaurus are an easy target.
[mewling]
[grunting, snarling]
[tense music playing]
They have no defense against this new type of reptile…
or even awareness of the threat it poses.
[snarls]
[snorts]
[mewls]
[squeals]
[snarls]
Like a fox in a chicken coop,
an Erythrosuchid can kill more than it needs.
-[faint cry] -[snarling]
Lystrosaurus was the unwitting dodo…
-[snarls] -[squeals]
…of its age.
A combination of predators and competition
saw Lystrosaurus go from total domination of the planet
to extinction.
[mournful music playing]
The mammals had lost their crown.
This…
[snarling]
…was the age of reptiles.
Today, there are more than 10,000 species of reptile…
although they are not all as terrifying as their ancestors.
As the Earth has changed…
[uplifting music playing]
…reptiles have had to adapt to an ever more crowded world.
And the tough, scaly skin
that allowed them to conquer the deserts of Pangaea,
continues to be the secret of their success.
For some, their skin has allowed them to become masters of disguise.
[uplifting music continues]
But skin can also be used to scare off an attacker.
[hisses]
Even then, there are times when more drastic measures are called for.
[music ends]
It may have escaped the bird,
but lizards aren't known for their swimming prowess.
Yet the anole lizard of Costa Rica has an extraordinary survival technique.
As it exhales, it creates a bubble that sticks to its water-repellent skin…
forming its very own diving bell…
and allowing it to stay hidden underwater
for up to 15 minutes.
Today's reptiles are such experts at living in the margins,
it's hard to imagine they once dominated our planet.
[birds tweeting]
[tense ambient music playing]
But there's a series of islands in Indonesia
that offer a glimpse into that very distant past.
For here, lizards still rule.
Recently hatched and already curious…
this youngster is starting life in a lizard paradise.
The only issue she has…
[ominous music playing]
…is her relatives.
For this is a baby Komodo dragon…
and Komodos are cannibals…
smelling the air with their forked tongue to find their prey.
[grunts]
For the world's largest lizards…
baby dragons make perfect snacks.
[grunting]
Luckily for her, a nest of buried Komodo eggs
offers an easier meal.
But it won't satisfy this monster for long.
[hisses]
It'll be seven or eight years of hiding in trees
before she's big enough to stand up for herself.
Too heavy to climb,
the adult goes in search of something more accessible.
[hisses]
[fly buzzes]
A thick layer of mud can't disguise this animal's scent.
[snorts, grunts]
[hissing]
[snorts]
Water buffalo are ever vigilant…
wary of their reptilian overlords.
[bleating]
But buffalo calves are not as savvy as their parents.
[suspenseful music playing]
[hisses]
[growling]
[calf bleats]
[buffalo grunting]
[snorting, grunting]
[dramatic music playing]
-[snorting] -[grunting]
The dragon has lost its kill,
but only temporarily.
Venom from a gland in its jaw
prevents the blood of its prey from clotting,
leading to a dangerous drop in blood pressure.
[somber music playing]
The result
is inevitable.
This is an echo of what life was like
back in the Triassic.
Mammals must fight for their lives,
while reptiles dominate with a confident swagger.
But perhaps the most remarkable chapter of that early era of reptile supremacy…
was when some of them turned their back on the land
and returned to the ocean.
[music fades]
[peaceful music playing]
Turtles.
Whether pushed here through competition
or enticed by opportunity…
turtles went back to the seas their ancestors left,
and today inhabit all but the coldest oceans.
Yet once a year, adult females must still return to dry land
to lay their eggs.
Here, on the edge of the Great Barrier Reef…
they come together in their thousands.
Aggregations like this
have been one of nature's greatest spectacles
for millions of years.
[music swells]
There's a good reason for this gathering.
Safety in numbers.
[music fades]
Turtles first evolved back in the Triassic.
But by the time they'd conquered the seas, the ocean was home to deadly predators.
At eight meters long, this is a plesiosaur.
[tense music playing]
It, too, is a reptile,
but one that spends its entire life at sea.
[tense music builds]
[music fades]
[crunching]
As the plesiosaur can only eat so much,
gathering in huge numbers like this
allows many more turtles to survive.
All that remains
is to haul themselves up onto the beach where they were born
and find the perfect spot to lay their eggs.
[poignant music playing]
Almost two months later, and the females' efforts are rewarded.
Hatchlings.
But each one now has its own gauntlet to run…
as they instinctively head towards the ocean.
[ominous music playing]
[dramatic music playing]
Pterosaurs.
Long before the existence of birds,
this group of ancient reptiles made a huge evolutionary step.
They took to the wing…
[squawking]
…and became masters of the air.
Totally defenseless…
this hatchling's only chance…
is to carry on…
ignoring the near misses,
and hoping that the pterosaurs will be spoiled for choice.
[squawks]
Every lucky escape…
[squawks]
…brings it closer to the water's edge.
Yet even those that reach the oceans aren't safe.
[squawking]
Only by getting to deeper water
can it avoid the pterosaurs…
and escape into the blue.
[stirring music playing]
Reptiles once ruled the skies and the waves.
But despite their supremacy,
Pterosaurs and plesiosaurs would both go extinct in time.
[stirring music continues]
[music fades]
Yet one of the ruling reptiles from this era has survived.
They're such perfect stealth hunters
that even after 200 million years…
little has bettered them.
[snorts]
Oblivious to the danger…
[snorts]
…wildebeest come to quench their thirst.
[tense ambient music playing]
[crocodile snarls]
[buffalo bellowing]
[snarls]
Almost.
But it doesn't matter.
The Nile crocodile knows the wildebeest will return…
just as they always have.
[snorts]
To avoid detection, the crocodile silently submerges…
holding its breath
for up to an hour.
[snorts]
Crocodiles can slow their heart rate to just two beats a minute…
almost completely shutting down…
in a way the reptiles perfected millions of years ago.
[tense music playing]
Yet in the moment it launches its attack…
it goes from inertia…
to explosive energy
in just a fraction of a second…
generating enough speed and power…
to launch its five-meter-long body…
out of the water…
all on an empty stomach…
and a single breath.
It's a technique as successful for crocodiles now
as it was for their prehistoric ancestors.
Today's crocodiles dominate the waters they live in…
but they are not the widespread predators they once were.
For back in the Triassic,
the forces of nature would send the story of life
in a completely new direction.
[rumbling]
Sustained volcanic eruptions caused another period of global warming.
[wind whistling]
As sea temperatures rose, they supercharged oceanic evaporation.
[thunder cracking]
In northern Pangaea, moisture-laden winds hit a 3,000-meter-high ridge…
creating megamonsoonal weather systems.
And it started to rain…
on a biblical scale.
[epic music playing]
[thunder cracking]
Across the planet, storms raged.
The downpours lasted more than a million years…
turning the dry deserts of early Pangaea into a distant memory.
In the far north, torrents flowed from high in the mountains.
[epic music intensifies]
[music fades]
Surface water rewrote the landscape…
carrying with it nutrient-rich silt.
The waterways soon covered more than 1.6 million square kilometers…
an area the size of Alaska,
creating the largest delta in Earth's history.
These fertile waterways became the lifeblood of a new world…
the fuel for evolution.
Conifers rose to the fore.
And for the first time since the Permian extinction…
our planet returned to a forested land of giants.
[rousing music playing]
Many ancient reptiles failed to adapt to this new landscape.
But one group embraced this change in plant life…
and would soon rise to take over the world.
[tranquil music playing]
The youngsters start life much like other reptiles.
They hatch from eggs…
they have scaly skin…
and they are left to fend for themselves…
[mewling]
…from the moment they enter the world.
[intriguing music playing]
But there are differences.
They have a much more efficient breathing system
that continuously pumps blood across their lungs…
allowing them to run
without having to stop to catch their breath.
[purrs, chirps]
Their legs extend beneath their body rather than to the side
so they can walk upright.
This allows tiny hatchlings to grow into adults
that are 50 times their size.
[soft thud]
They're part of the reptile family tree,
but are their own unique branch.
[majestic music playing]
Early giants, like Plateosaurus,
can reach the new taller food sources.
[bellows]
Their stomachs can digest the tough conifer needles…
and their sheer volume
helps them maintain a higher body temperature
day and night.
It's a winning formula that will herald a new age.
[music intensifies, then ends]
The Jurassic.
[stirring music playing]
This new dynasty would rule
for more than 150 million years.
[stirring music continues]
A reign that would see the rise of some of the most iconic creatures
to ever walk the Earth.
Welcome to the age of dinosaurs.
[bellowing]
[epic instrumental music playing]