Prehistoric Planet (2022) s01e04 Episode Script

Ice Worlds

Surely, one of the most remarkable animals that has ever existed, and certainly one of the most famous, is a dinosaur.
Tyrannosaurus rex.
An animal to spark the imagination for all of us.
What kind of an animal was it? What did it look like? How did it live? Now, scientific research has answered such questions.
And not just about T.
rex, but the other species that lived alongside it.
And the latest imaging technology enables us to bring them all to life.
Planet Earth, 66 million years ago.
The skies are filled with flying giants.
In the seas, monstrous reptiles patrol the depths.
And on land, dinosaurs of every kind, all facing the struggle to survive.
We now know so much about a world that was ruled by the dinosaurs.
This is their story.
Life is at its harshest in the far north and south of planet Earth.
Dinosaurs, however, have managed to colonize these polar regions.
In the far north of America, this tiny hunter, a dromaeosaur, has managed to survive three months of near-total darkness.
And now, at last, spring has come.
She has a coat of feathers, for she's able to generate heat in her body and needs to retain all she can.
A challenge for all dinosaurs in these cold latitudes.
As she moves quickly over the surface of the snow, she checks on the places where she has found food in the past.
In this icy world, no opportunity is too small to be ignored.
And to succeed, as usual, you need good timing.
Although at this time in Earth's history, the polar regions are relatively warm, these lands are, nonetheless, ruled by extreme seasonal change.
When the sun rises for the first time in almost three months, every animal must be ready to make the most of the daylight and the warmer days that are to come.
The little dromaeosaurs must work together, if they are to take on big prey.
And here comes their first chance of the season.
A herd of hadrosaurs.
These duck-billed dinosaurs pass through here every year.
Nomads in search of the fresh vegetation brought by the spring.
They're huge.
The only chance the dromaeosaurs will have is to work as a team.
There's a river ahead, which the herd will have to cross.
And the dromaeosaurs know that some never make it.
As winter slackens its grip, meltwater begins to flow with great power.
The herd must wade through this deep, fast-flowing water.
The leaders try to select the safest crossing.
The herd follow cautiously.
Young keep close to their parents.
Putting a foot wrong here could cost them their life.
The adults, awaiting their turn, grow nervous.
And this bottleneck gives the dromaeosaurs a chance.
Their target will be the young.
Panic begins to spread through the herd.
What should have been an orderly crossing turns to chaos.
Parents and young are separated.
A lucky escape.
The column re-forms and continues its journey.
The dromaeosaurs seem to have missed their chance but the river has done their work for them.
There are always casualties.
It's a feast.
And more food than these hunters have had all winter.
In the ice world, seasonal opportunity is brief.
Spring is short, and summer will soon be over.
There's a lot to be done before the challenges of winter return.
Downstream, as the rivers broaden and begin to slow, they start to drop their loads of silt, and a network of islands appears.
Some animals have already seized the moment to assemble for the spring rituals.
Spring, at last, has truly arrived.
Dozens of male Ornithomimus are preparing for the most important moment of their year.
These strange ostrich-like dinosaurs choose the safety of these islands to scrape out shallow craters, the first stage in making a nest.
When the females arrive, they will choose to mate with the males who've made the best one.
Late arrivals find that space is already in short supply.
The only space left is on the island's margin.
And finding a place to nest is only just the start.
When eggs are eventually laid, they will need to be kept warm in a bed of vegetation.
Finding enough nesting material is not easy which is why some Ornithomimus resort to thievery.
One advantage of arriving late is that your neighbors have already done the hard work.
An unguarded nest is too much of a temptation.
In colonies like this, thievery can be so common that some nesting material, at one time or another, will have been part of almost every nest on the island.
But robbery is risky.
Caught in the act.
A couple of hadrosaurs wander by.
They will eat leafy branches.
So, you have to be able to defend your property.
It can take several years to perfect nest-building skills.
But success doesn't only rely on experience.
In a crowded colony, there's always another potential victim.
For Ornithomimus, these river islands will provide sanctuary for both the eggs and the young when they hatch.
Further north, temperatures are lower and conditions are tougher.
Yet that's where these enormous crested hadrosaurs are heading to take advantage of one site in particular.
One that has something special to offer.
The long necks of these dinosaurs are particularly elegant and give them their name.
Olorotitan, "Giant Swan.
" Their calls are amplified by their head crests, which are hollow.
They're heading for one of the world's largest volcanic regions.
It's a dangerous and hostile place.
But the Olorotitans return to it, year after year because the volcanoes keep the ground particularly well-heated.
So, this is where they nest.
The warm volcanic sand serves as an incubator for their eggs.
And a few weeks after the arrival of the herd, the eggs hatch.
Hadrosaurs look after their young with care.
They bring mouthfuls of plants for them to eat.
Each nest may contain over 20 youngsters.
The babies have arrived at a time of brief but rich summer plenty.
Fueled by a sun that for weeks never sets, horsetails here grow fast and in sufficient numbers to feed the whole herd.
These plants contain more nutrients than the lushest grass.
And in the long summer days, the hadrosaur babies grow quickly.
They can reach half their adult size in their first year.
Right now, these volcanic wetlands are the most productive places on the planet.
Both above and below the surface of the water.
But that very productivity brings problems for the hadrosaurs.
Warm, shallow pools are an excellent breeding ground for mosquitoes.
Every year, this paradise turns into a living hell.
Hadrosaurs have surprisingly thin skin, and so, have little defense against bloodsucking insects.
Constant irritation makes it hard to feed, and they become dangerously weakened.
And babies can lose blood in life-threatening quantities.
Eventually, the herd is forced to move on to escape the plague.
If the young can't keep up, their mothers abandon them.
As they go higher, stronger winds bring some relief.
But only for those able to walk that far.
Of the hundreds of hadrosaur babies born, only one in ten survives their first year.
But those that do have a good chance of reaching adulthood.
By nesting in this volcanic valley, the parents give their young the best possible start in life.
Although the short and warm polar summer is a time of great plenty, it can also bring perils.
Warm air rises and becomes charged electrically.
And that creates frequent and violent lightning storms.
In the north of America, the lush growth fueled by constant sunlight has now been baked tinder-dry.
Most animals flee from the flames.
But for some, the disaster creates opportunities.
This six-foot-long dinosaur, a troodontid, is one of the smaller members of the theropod group.
Its huge eyes give it acute sight, even in this smoky gloom.
And for its size, its brain is one of the largest on the planet.
It's the most intelligent, adaptable, and successful hunter in the Arctic.
At the fire's edge, troodontids gather to prey on animals that are trying to escape the flames.
Anything that spreads the fire creates more opportunities for the most ingenious arctic hunter of its time.
With the short summer over, the forests that survived the summer fires start to change color.
It is autumn's final flourish before the months of darkness begin.
In the Antarctic, ice clings to the highest mountains even in the summer months.
But now, with temperatures falling and the day's shortening, the polar winter is spreading once more across the land.
Animals must now prepare for its return.
The southern hemisphere has its own species of dinosaurs.
These three are young Antarctopelta, small plant-eating dinosaurs.
They're also one of this world's most heavily armored animals.
Even so, youngsters are safer together.
This far south, the plants on which they depend stop growing for months on end.
As winter approaches, these juveniles spend more time resting.
Sheltering together conserves heat and, therefore, energy.
With powerful front limbs, they can enlarge this winter den.
But each time they return, they've grown a little bigger.
Their den seems a little smaller, and the brotherly bond starts to wear a little thin.
For every growing animal, this is a vulnerable time.
A time when they need to separate and each take its first tentative steps to find a territory of its own.
Herds of hadrosaurs are once again on the move.
With little to eat, these huge herbivores return to look for food in warmer lands leaving others to endure the freezing polar winter.
Finding a suitable territory can take animals far from the place where their lives began.
It's a search that many will not survive.
A good territory must have a place in which to shelter.
A cave, perhaps.
Even in the coldest months, the temperature in most caves hardly varies.
But he is not the first to be attracted by this one.
This cave glows.
These are the tiny lures of fungus gnat larvae that produce light to attract their insect prey.
This is the perfect place for an Antarctopelta to escape the worst winter weather.
He will be safe beneath these strange living stars while outside, snow begins to fall.
In the coldest months, the far north of the Arctic can freeze into a spectacular winter wonderland.
Not all dinosaurs choose to leave or to seek shelter.
The largest have the strength to tough it out.
Two-ton herbivores with extravagantly armored heads.
They seek refuge in the forest, stripping the last leaves from dormant trees and rooting through ferns for fallen fruit.
The autumn rut is over, but less dominant males still try to push their way up the social hierarchy.
But they've forgotten who's in charge.
This old bull is still a formidable force and one that few dare to challenge.
Battling males barely have time to eat or rest.
With food now scarce, it's hard to rebuild strength, and injuries take longer to heal.
To make matters worse the Arctic's most powerful predator is always on the prowl.
A smaller relative of T.
rex, it's still just big enough to tackle a pachyrhinosaur.
For these ancient adversaries, in these conditions, the battle will be resolved not by surprise, but by strategy.
Amongst the trees, it's hard for the herd to stand as one.
Individuals could be quickly isolated.
The nervous herd makes a tactical retreat to open ground.
The nanuqsaurs follow.
Out here, the herd will be able to close ranks and form an impenetrable wall of armored heads and muscle.
The blizzard worsens.
It's an uneasy standoff.
These confrontations can last for days.
The herd should be safe as long as they stick together.
But the nanuqsaurs bide their time and occasionally test for weakness.
The blizzard now brings a temporary truce.
But as soon as it's over, battle resumes.
In this test of nerve, all it takes is for one animal to break ranks and panic quickly spreads.
With the herd on the run, the predators have a chance.
As the chase goes on, one tiring bull fails to keep up with the rest.
Until all he can do is turn and face his attackers.
One pachyrhinosaur has lost the battle.
But the war will go on all winter.
The animals here now face months of total darkness before the sun returns and brings relief to the extraordinary creatures in the world of ice.
Next on Prehistoric Planet, a flying giant the size of a giraffe hunts its prey amongst the tangled trees of a prehistoric forest.
And under the canopy on this green planet, dinosaurs ambush, display, and even journey underground.
To discover the science behind the stories, go now to the Prehistoric Planet show page.

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