Two hundred and fifty-two million years ago…
…And our planet is dying.
The biggest extinction event in history has left the world barren.
And deathly silent.
But this is the story of the few…
…That survived.
LIFE ON OUR PLANET
CHAPTER 4
IN COLD BLOOD
252 MILLION YEARS AGO
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…
…İn a crust up to three kilometers deep.
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.
Lystrosaurus.
An ancient ancestor of the mammal.
This curious, big-sized creature was used to burrowing underground and seeking
refuge in caves.
A way of life that saved it when other animals were dying.
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.
But Lystrosaurus are resilient and able to forage over large areas.
They're constantly on the move… searching for roots, tubers and small
pockets of regrowth.
But they weren't the only animal survivors.
Life in many forms…
…Found a way.
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 borrower…
…To the animal that inherited the Earth.
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.
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.
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 Pangea.
The drying that started in a previous era…
…İs now compounded by searing heat.
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.
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.
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.
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.
The challenge is catching them.
Finally.
But just when it thinks it's cracked it… trouble on the horizon.
These prime fly-catching spots are in high demand.
And the locals do not like to share.
A stalemate. But on another lizard's territory…
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, Lystrosaurus have
dominated.
They emerged into an almost empty world.
And have been reaping the rewards.
Life is good.
But these mammal ancestors… have had little competition or predators.
Until now.
With the planet recovering, some reptiles have grown to epic proportions.
This is an Erythrosuchus.
Nearly three meters long, it's the biggest predator of its time.
Herds of Lystrosaurus are an easy target.
They have no defense against this new type of reptile.
Or even awareness of the threat it poses.
Like a fox in a chicken coop, Erythrosuchus can kill more than it needs.
Lystrosaurus was the unwitting dodo… of its age.
The combination of predators and competition saw Lystrosaurus go from total
domination of the planet…
…To extinction.
The mammals had lost their crown.
This…
…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…
…Reptiles have had to adapt to an ever more crowded world.
And the tough scaly skin that allowed them to conquer the deserts of Pangea…
continues to be the secret of their success.
For some, their skin has allowed them to become masters of disguise.
But skin can also be used to scare off an attacker.
Even then, there are times when more drastic measures are called for.
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.
But there is 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…
…İs her relatives.
For this is a baby Komodo dragon.
And Komodos are cannibals.
Smelling the air with their forked tongue to find their prey.
For the world's largest lizards…
…Baby dragons make perfect snacks.
Luckily for her, a nest of buried Komodo eggs…
…Offers an easier meal.
But it won't satisfy this monster for long.
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.
A thick layer of mud can't disguise this animal's scent.
Water buffalo are ever vigilant.
Wary of their reptilian overlords.
But buffalo calves are not as savvy as their parents.
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.
The result…
…İs 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.
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 the thousands.
Aggregations like this have been one of nature's greatest spectacles for millions
of years.
There's a good reason for this gathering.
Safety in numbers.
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.
It, too, is a reptile… but one that spends its entire life at sea.
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.
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.
Pterosaurs.
Long before the existence of birds, this group of ancient reptiles made a huge
evolutionary step.
They took to the wing…
…And became masters of the air.
Totally defenseless…
…This hatchling's only chance…
…İs to carry on…
…İgnoring the near misses… and hoping that the Pterosaurs will be spoiled for
choice.
Every lucky escape…
…Brings it closer to the water's edge.
Yet, even those that reach the oceans aren't safe.
Only by getting to deeper water…
…Can it avoid the Pterosaurs…
…And escape into the blue.
Reptiles once ruled the skies and the waves.
But despite their supremacy, Pterosaurs and Plesiosaurs would both go extinct in
time.
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.
Oblivious to the danger…
…Wildebeest come to quench their thirst.
Almost.
But it doesn't matter.
The Nile crocodile knows the wildebeest will return.
Just as they always have.
To avoid detection, the crocodile silently submerges.
Holding its breath…
…For up to an hour.
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.
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.
Sustained volcanic eruptions caused another period of global warming.
As sea temperatures rose, they supercharged oceanic evaporation.
In northern Pangea, moisture-laden winds hit a 3000-meter high ridge…
…Creating mega monsoonal weather systems.
And it started to rain.
On a Biblical scale.
Across the planet, storms raged.
The downpours lasted more than a million years…
…Turning the dry deserts of early Pangea into a distant memory.
In the far north, torrents flowed from high in the mountains.
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.
210 MILLION YEARS AGO
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.
The youngsters start life much like other reptiles.
They hatch from eggs.
They have scaly skin.
And they are left to fend for themselves…
…From the moment they enter the world.
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.
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.
They're part of the reptile family tree… but are their own unique branch.
Early giants, like Plateosaurus, can reach the new taller food sources.
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.
The Jurassic.
This new dynasty would rule for more than 150 million years.
The reign that would see the rise of some of the most iconic creatures to ever walk
the earth.
Welcome to the age of dinosaurs.