The Future is Wild (2003) s01e05 Episode Script

Imagine a world, millions of years in the future.
A world where evolution has written a new chapter in the story of life.
The world is inhabited by very strange creatures, like nothing the Earth has ever seen.
the FUTURE is WILD COLD KANSAS DESER Five million years in the future, a harsh, bleak desert.
But the problem for anything living here isn't the heat it is the cold.
This is an ice age desert.
Strange animals feed on what little vegetation there is.
And on each other.
There is little water here and the strong, cold winds blow continuously from the northern ice caps.
This desert was once the richest agricultural land in North America.
But in this future ice age, 2 kilometre high ice sheets have reached as far south as Chicago, turning the remaining wheat belt into a cold, dry landscape.
Hundred kilometre an hour winds whip up the sand and dust, scouring the desert.
This is a rattleback and her baby.
And rattlebacks are among the few animals that can survive in the open during such a sandstorm.
The grubby vegetation doesn't give any real shelter and the rattlebacks just keep going, struggling on through the wind.
The only protection they have are their scales and each other.
There are animals in this desert, but they all have to be specialised to survive the difficult conditions.
One of them is the rattleback.
The rattleback we have here has evolved from the rattleback we saw in the grasslands of South America.
The grassland rattleback has scales that it uses for display and defence.
Rattlebacks evolved from the South American rodents and are very successful.
They quickly spread from their ancestral grassland home into North America.
The South American rattleback has strong armoured scales as a defence against the predators of the Amazon prairies, but the desert rattleback looks very different.
It is not so heavily armoured as there aren't so many big predators in the desert.
But its scales give it the perfect defence against sandstorms.
They have become smaller and more closely linked and its face is covered in thick hair, all protection against the abrasive power of sand.
The other adaptation it has is, unlike its ancestor, it has got a large tail.
It doesn't have to worry because it hasn't gone such big predators that could grab hold of it.
And that tail serves as a fat reserve at times of food shortage and also as a water source.
There is no water to drink, and the rattlebacks have to travel several kilometres every day just to find food.
And most of that is hidden below the ground.
Some creatures, like these spinks, survive the worst of the desert by living underground.
And their world is being invaded.
But the rattleback isn't trying to reach the spinks, all it wants is the tuber, the fleshy root of a plant that grows in the sandy soil.
The tuber provides food and water for the hungry rattlebacks.
Animals in this desert have got to find a way to survive, they have got to have mechanisms which will enable them to survive through the year in periods when there is better food and periods when there is much less.
One place where the desert environment is much more secure and predictable is underground.
Now here we have a bird which burrows.
So, although it may not look like it, this spink is a bird.
It's a bird which is evolved from the galliform birds.
These are birds like pheasants and partridges and grouse.
They are already species which spend a lot of time on the ground.
That group also included quails, the ancestors of spinks.
Today, quails live across most of North America.
They can fly, but spend most of their time on the ground.
So it wasn't too big a step for them to burrow underground.
The quail became smaller, its body lower to the ground, and it lost the power of flight.
Its feathers are now much smaller, forming a layer of insulation, just like the fur on a mammal.
Very fine feathers around its face, keep sand and dust out of its eyes.
Its wings have become front legs, so it walks on all fours, but the main role of its wings is digging.
The feathers are made of keratin which is the same thing that makes up fingernails and beaks and so on.
Keratin is replaceable, it is lightweight, it is tough, and if you adapt those feathers into a sort of spade, then this can be used to dig.
The spinks dig long tunnels under the desert, scraping away at the soil with their beaks and wings.
Birds digging and living-in tunnels, might seem strange, but today there are birds that do something similar.
Puffins nest in burrows that they dig into a cliff top.
They have toes on their webbed feet with claws strong enough for digging.
A pair of puffins dig a burrow between them, but it only goes a metre so underground.
Kingfishers also dig burrows about the same length into riverbanks.
And bee eaters cover a whole cliff face with their burrow entrances.
But all these birds just use their burrows for shelter and for rearing their young.
The spinks, though, spend nearly all their live in the darkness of their tunnels.
The main reason the spink spends so much time underground is because of it is food it is looking for tubers.
By digging its burrows it is finding plant the plant food material.
It has very special requirements for its colony, and it has evolved a type of mechanism of organising the colony that we see rarely today very rarely in vertebrate animals but a little more often in insects.
To dig such a big tunnel system, the spinks work together.
They have a caste system, where worker spinks do all the digging to extend and maintain the tunnels.
Deeper underground, are larger chambers, where breeding female spinks, the queens, sit on eggs, most of which will hatch into new workers.
All the colony members communicate with each other by singing.
They use a high pitch for short distances, and a lower frequency for long range communication around the colony.
Spinks live in big colonies because the tubers they feed on are scattered widely across the desert.
They can only build a big enough network of tunnels by living in a complex society, with a dedicated caste of workers.
A similar division of labour does happen today.
Naked mole-rats lived in huge colonies underground, digging tunnels to feed on roots.
Most of these mole-rats are workers they will never breed, but instead, spend their lives digging tunnels.
Naked mole-rats dig with their teeth, which keep growing.
Spinks dig with their beaks, which also grow continuously, but they coordinate their digging, working like a chain gang.
The spink at the head of the tunnel loosens the sand and kicks it back to a spink behind.
The next spink passes it back further down the tunnel, to yet more spinks.
As the tunnel and grows, more workers join the chain gang.
Eventually, the last spink in line opens a tunnel to the surface, and kicks the sand out.
These miniature sand volcanoes attract the attention of the hungry rattleback and her baby.
On their long search for food, they know that where there are spinks, there are bound be tubers.
So this will be a good place to dig.
The rattleback's digging also attracts attention the attention of deathgleaners.
Huge, predatory bats with a meter wingspan.
Deathgleaners fly during the day, cruising over the desert, searching for anything they can find to eat.
Dead or alive.
But they are not after rattlebacks.
The rattleback's enthusiastic digging for tubers has exposed those spinks unlucky enough to be close to the surface.
The unearthed spinks run for cover, and it is these that the deathgleaners are waiting for.
On the surface, spinks are helpless.
Just bite size snacks for deathgleaners.
The deathgleaner is basically a carnivorous bat it will both hunt prey and it will scavenge.
So it will eat carcasses if it can find them, but out in this arid environment there aren't too many carcasses.
So the other thing it does is it actually hunts, following the rattleback as a rattleback digs up its tubers, it disturbs spinks, spinks come up to the surface and the deathgleaner grabs them.
So the rattleback does all the work, digging through the hard desert soil, and the deathgleaner gets a free lunch.
It might not seem fair, but it happens today as well.
This kind of goshawk in Africa is often found hanging around honey badgers.
When the honey badger uses its strong paws to dig for food, the goshawk follows it, watching and waiting.
It knows the honey badger will dig up insects or small reptiles, which the goshawk will try to steal.
In the future, it is a carnivorous bat that has learned to exploit other creatures.
But a giant predatory bat sounds like a nightmare vision of the future.
Yet, even today, within the forests of Central America, there are fearsome predatory bats.
They are much smaller than deathgleaners, but still effective killers of small reptiles and mammals.
And it is possible that bats like these, could respond to the spreading cold desert by growing much larger.
Being big, deathgleaners can soar for vast distances over this sparse landscape, searching for the dead, dying or vulnerable.
Bats are mammals, and a warm blooded mammal flying in a cold desert faces a problem.
The problem it has is that these wings are naked, it will lose a lot of heat through these wings and so it has a very clever adaptation.
It has got a counter-current system in its wings.
So, as the blood goes out into the wings, it is cooled - the heat is passed to the incoming blood to warm it up, so it effectively loses very little heat through the blood.
There is cold blood in the wings and it is warmed up as it re-enters the body.
As the sun begins to set, the deathgleaners have to return to their roost, to avoid the cold of the night, when temperatures drop to freezing.
They all gather at a communal roost, inside the cave.
Hundreds of deathgleaners make their way here, returning from their separate hunting trips during the day, flying in from all directions.
The desert is a pretty inhospitable place.
The deathgleaner will travel long distances looking for food, but it still then may not be successful.
But it has a reserve strategy.
It goes home to a communal roost, and there, some at least, of the deathgleaners will have been successful in foraging.
So they will share food so that all of them get enough to survive upto the next time they can go foraging.
Such a strategy is not uncommon vampire bats, for instance, do it.
Not all the bats in the night will get enough blood to drink.
When they go home, those that have been successful pass on some of their food to particularly their relatives, and so it helps them all survive.
Today, vampire bats can drink up to 60% of their body weight in blood in one night.
But if they don't feed every two or three days, they will die.
So vampire bats depend on their social system for survival.
With the deathgleaners safely in their roost, the desert night comes alive.
Underground, the queen spinks have produced eggs that hatched into reproductive spinks new queens and kings.
Males emerge first and assemble on display grounds.
The females leave the tunnels later, but they don't head for the nearest displaying males.
They leave their own colonies to find the display grounds of distant, unrelated, males and when these females reach a new group of males, the males try to impress them with their signalling.
A few birds use such communal display grounds today.
Black grouse are in the same family as the spinks' ancestors, and they come together in groups, where the males strut around to impress the watching females.
The most desirable territories are in the centre, making it easy for females to pick out the fittest males.
Five million years in the future, and evolution still works the same way.
Male spinks, compete for territories near the centre of the display ground.
When that the female spinks have made their choice, the spinks pair off to mate and start a new colony.
But this whole display has to be over by sunrise when the deathgleaners take to the skies again.
Any spinks still on the surface have to find cover wherever they can.
The survivors will start their new colonies underground, creating new tunnel systems all out of the way of deathgleaners.
With the spinks all safely back underground, the deathgleaners will have to look elsewhere.
In their search for food, the mother and baby rattlebacks have become separated.
The baby rattleback is not too big for the deathgleaner's powerful jaws.
As they come in for the kill, the baby can only call for help.
But its mother has heard it.
And the deathgleaners won't take on an adult rattleback.
Her rattling scares them off, and anyway, they won't risk tearing their fragile wings on her sharp scales.
In such harsh, extreme conditions, it is important for the rattlebacks to care for their young.
A mother and her baby must stay together for many years until the baby has learned all the tricks it takes to survive in this harsh world.
The spinks have another solution to living here to move underground, sheltered from both the harsh climate and predators.
But whatever survival tricks evolution has come up with, this is still a hard place to make a living.
Freezing winds, blinding dust storms.
In five million years time, this certainly doesn't look like Kansas any more.