Deluge Wonders of the Monsoon

The monsoon.

The greatest weather system on Earth.

Giver of life...

and the destroyer.

Shaping magical lands

from the Himalayas

to Australia.

Its impact felt by giants.

The exquisite

and the bizarre.

Where spectacular nature meets the planet's most vibrant cultures.

This is the story of the monsoon at its most extreme.

Each year, from Cambodia to India,

the hot months of summer herald a life-changing deluge.

It brings great danger...

..and enormous opportunity.

There's a mystical world

where tree roots reach across the sky.

A twisted landscape that holds its breath

in anticipation of the coming storm.

Beneath the surface, a giant stirs.

She must act while there's still time.

She's a frog-faced soft-shell turtle.

Her eggs must develop in dry sand,

before the monsoon turns their world upside down.

This is the "mother of water" - the Mekong.

It's April in Cambodia, and the first rains are yet to arrive.

After two months, incubating in the sand,

the baby soft-shelled turtles are emerging.

They must reach water,

but first, they have a desert to cross.

Their shells are just rubbery skin, light and flexible.

Their flattened shape will be key to their survival.

They will spend their lives hidden in the sand.

Here they are ready for anything the monsoon will throw at them.

Everyone seems restless.

Cormorants are waiting to nest on a nearby lake.

But most of the lake bed is dry.

This village sits where the lake should be.

It's a fishing village...

with no fish.

Cambodians depend on freshwater fish more than any other nation on Earth.

So they need the rains to flood this land.

For kids like Thom,

the world revolves around an annual wonder of nature.

The summer deluge and the gifts of the Mother River.

The Mekong flows south from the Himalayas for over 2,500 miles,

feeding six countries across South-East Asia,

including Thailand, where rain clouds are building.

THUNDER RUMBLES

It's May.

The monsoon begins with a whisper on the wind.

A pre-monsoon shower.

THUNDER RUMBLES

Not yet the full deluge,

but enough to spark a little magic in the forest.

It's been bone dry for months.

So, for young Assamese macaques, this is a new experience.

But their parents know the rains deliver something

much more enticing.

If only they could find it.

A water snail.

Delicious!

These snails survived the drought under rocks,

locked away in their shells.

Winkling them out is fiddly...

..so the monkeys pocket them in their cheek pouches

to be enjoyed at leisure.

As spring turns to summer, warm air rises over the land,

sucking in moist monsoon winds from the Indian Ocean.

Storm clouds form at sea.

In India, the southern state of Kerala is where they strike first.

It's June.

WIND HOWLS

The long wait is over.

THIS is the Indian monsoon.

Heavy, unceasing rain.

Rainfall is usually measured in millimetres,

but during the monsoon, a metre can fall in just a day.

Clouds roll in.

Wave after wave.

Even if the fierce sun breaks through, the dampness never dries.

For four long months, the deluge overwhelms the land...

..transforming the lives of everyone and everything.

Like the great Hindu god, Shiva, the monsoon can be a destroyer,

bringing chaos and destruction.

But, like Shiva, it also brings rebirth, and new life.

The challenge for all, is not simply to survive the monsoon,

but to grasp every opportunity it offers.

Puddles and pools are forming everywhere.

Perfect for frogs...

and toads.

For this female Indian common toad,

the first rains mean she can breed at last.

And she must hurry, for it's a one-day event.

A suitor awaits.

In fact, there's a whole crowd of them.

Prompted by the monsoon rains,

the males have all turned yellow for this one special day.

They may dress to impress, but they don't waste time with niceties.

You might think the colour would help tell the girls from the boys,

but it doesn't seem to make any difference.

After all, today could be their only chance

to sire a new generation.

The first tadpoles to hatch out will have a crucial head start

in the race to grow before the waters recede again.

Just two weeks after the first rains,

another creature begins to emerge from the monsoon pools.

Having grown up as an aquatic larva,

the adult mosquito is water repellent.

Her mission is also to reproduce.

But it's a dangerous new world for one so small.

Raindrops can reach speeds of nearly 20mph.

For a mosquito, you might think that's like being hit by a bus.

But scientific research has recently revealed how mosquitoes

flying in the monsoon cheat death.

They are so water-repellent,

that most raindrops simply glance off them.

A direct hit looks fatal...

..but the insect is so light and flexible

that she can absorb the impact and shake off the drop,

as though nothing had happened.

Insects multiply.

For many, they are the monsoon's curse.

Female mosquitoes need blood to grow their eggs.

Cases of malaria increase by ten times during the monsoon.

It brings perils...

but also wonders.

This is the magic of the monsoon.

Beneath the building cloud,

India is transforming.

But in the driest parts of the interior,

the land will take longer to turn green.

Here, Indian wolves await the monsoon's bounty.

This female gave birth back in winter

and the pups must soon be weaned.

She is staking their lives on the monsoon to bring them fresh meat.

WOLF HOWLS

Sheep and goats are the staple diet of most Indian wolves...

..and they go where the grass is greenest.

A journey where old India meets new.

Mahendra leads his livestock, and his extended family,

on a never-ending quest for fresh pasture.

They've been on the move for eight months.

Now, with rain on the way, they're heading for their homeland.

The striped hyena is the wolf's main competitor

and will often chase a wolf from a carcass.

She, too, needs to hunt if she is to provide milk for her cubs.

Home at last, just ahead of the monsoon rains.

They will soon turn this barren land green again.

The only the protection the sheep will have is a flimsy net

and it must be up before sundown.

Guard dogs have nail-studded collars for their protection.

It's at night that the predators will come.

When the light fades,

a thermal camera reveals what the naked eye can't see.

Warm bodies glow white.

The net is not secure.

Hyenas.

Their scent drifts on the wind.

DOGS BARK

The dogs have been bred to be fearless...

..and the hyenas can't afford to risk injury.

Wolves.

A wolf bit through the top rope of the net.

Mahendra is surprisingly philosophical.

For him, it's a small price to pay

for the bounty he hopes the monsoon will bring.

By the end of July, all of India,

from the coast to the Himalayas, is transformed by a cloak of green.

This is Rudyard Kipling country.

The Jungle Book in all its splendour.

Baloo, the sloth bear, knows the rains will bring tasty termites.

Colonel Hathi and the troop have eked out a living

on leaves, twigs and bark,

but now fresh grass means they can range free and wide.

For Shere Khan, the monsoon is a double-edged sword.

Chital deer no longer gather at waterholes

where they can be easily ambushed.

But the fresh growth nurtures a new generation of prey.

The chital team up with langur monkeys.

The deers' noses and the langurs' eyes alert to potential danger.

Everywhere there's danger and opportunity

and both increase as the monsoon rains continue.

At their peak,

17 million tonnes of water fall on the subcontinent every minute.

Right across southern Asia,

rivers have become swollen with monsoon rains.

Along the Mekong, it's what all of life has been waiting for.

The flow of the Mother River has increased 400%

and now her influence is colossal.

She has created a whole new habitat.

A flooded forest, where fish swim.

Now is the time for them to feed and grow fat.

But it's never safe to loiter.

The soft-shelled turtle can strike faster than a cobra.

Downstream,

the monsoon is responsible for an extraordinary phenomenon.

The Mekong is met by the River Sap, which flows from a large lake.

The river's natural flow is from west to east, into the Mekong.

But the Mekong becomes so swollen with monsoon rain

that it pushes water uphill, back up the Sap River.

The river's flow has reversed...

..taking with it, huge numbers of fish.

They head for the lake, called Tonle Sap,

which balloons to eight times its former size.

A vast inland sea that swallows up around a tenth of Cambodia.

Thom's world is now transformed.

His village can now only be reached by boat.

Nurses paddle to their patients

and traders punt their wares from door to door.

There is no longer any dry land to grow vegetables.

And they keep their pigs in floating sties.

But they can trade fish and shrimp from the lake for other goods.

So Thom and his dad go fishing every day.

The lake is vast.

And full of millions of fish.

They swam in from the Mekong and are now in fish paradise.

In these warm, rich waters,

young fish rapidly grow to maturity.

And the drowned trees offer much needed protection

from the most skilful of predators.

Cormorants have flown in from the Mekong,

joining resident colonies of Oriental darter,

known also as snakebirds, on account of their necks.

This bird is a beautifully adapted fish hunter.

It has a hinge in its neck,

with powerful muscles that thrust its head forward like a spear.

It submerges to hunt underwater.

Dense bones keep its body below the surface,

so it dives with barely a ripple.

But fishing is a skill that has to be learned.

This youngster has just left the nest to enrol in snakebird school.

Other students are already training.

But where are the fish?

No, just a leaf.

But that's OK.

She is honing a vital skill.

If she impales a fish,

she needs to flick it off her bill and catch it headfirst.

All the youngsters are practising.

Perseverance eventually pays off.

She's well on her way to independence.

Elsewhere, the monsoon floods are not always so benevolent.

At the Bay of Bengal,

the Indian Ocean reaches closest to the Himalayas.

Monsoon rain clouds collide with the mountains,

creating the wettest region on Earth.

Through the middle flows the mighty Brahmaputra.

And bordering the river is Kaziranga National Park...

..home to giants.

This youngster was born in the dry season.

Even then, there was water, and she has spent many days

finding her feet in the deep pools. She still has much to learn.

In the heat of the day, the elephants wallow

amongst the floating water hyacinth.

It's a delicacy, but first, it has to be washed.

It takes a bit of practice.

And she must avoid the grumpy neighbours.

Indian one-horned rhinos don't like company.

Even the mud is quite a challenge for little legs.

But a much graver danger is approaching.

The monsoon is about to deliver a devastating blow.

The rains have been exceptionally heavy this year

and the Brahmaputra has burst her banks, flooding the plains.

The National Park is fast disappearing.

The elephants must escape.

Small creatures are flushed from the undergrowth.

But they have nowhere else to go.

The floods show no mercy.

The Park is now beneath five metres of water,

too deep even for elephants.

They must reach the safety of the hills.

Not even water buffalo can survive in this much water.

Solid ground, but this is no place for elephants.

Many animals have died making this crossing.

Hog deer are nimble.

But the elephants must wait.

It's still a long way to the hills,

and the herd is now outside the protection of the Park.

Thousands of people have had to leave their homes.

It's a national disaster.

Everywhere, people and animals are fleeing the rising waters,

and when their paths cross, neither is safe.

A lone bull elephant is desperate for dry land.

But the villagers are afraid for their houses and their lives.

He'll have to seek sanctuary elsewhere.

The hills.

They've all survived.

For this youngster, it's been a dramatic awakening

to the terrifying power of the monsoon.

As fast as they rose, the floods recede.

It's a good time for scavengers.

Griffon vultures have found a dead rhino.

The stench is overpowering.

But this tiger has sniffed out an opportunity.

Why waste energy hunting when such a feast is here for the taking?

He has strong jaws and a strong stomach.

Though it can be devastating, the monsoon is also a provider.

And it is about to make its greatest gift.

As the waters recede, they leave everything coated in fine silt.

Like a sprinkling of magic dust, it is this that creates fertility,

and new life.

Kaziranga's elephant grass grows to over five metres.

All along the Brahmaputra, it's the same story.

Downstream, in Bangladesh,

monsoon floods cover up to 70% of the entire country.

But here, the Brahmaputra joins the Ganges to create

some of the most fertile soils on Earth.

In places, the silt lies over half a mile deep.

By October, the days are shortening, the air cools,

and the monsoon rains come to an end.

In Cambodia, Tonle Sap lake is emptying again,

and fishermen face six months of drought.

Tola has been fishing on the River Sap

every day for the past few months.

But with such a vast area for the fish to hide,

their catches have been modest.

He has a growing family to feed through the dry months ahead.

So they preserve the catch by making prahok, a kind of fish paste.

It helps, but it won't be enough.

But the monsoon has a final parting gift

for those with the ingenuity to grasp it.

Falling water levels trigger a mass migration.

Millions of fish flee down the Sap River from the shrinking lake.

The challenge is how to catch them.

Enormous nets are erected for this one fleeting event.

Tola has signed up to join one of the fishing crews.

But with many channels, no-one knows when or where the fish will run.

Each crew gambles on one channel or another.

Tola must hope he has joined the right team.

They're about to bring up their first haul.

Will it be feast or famine?

A tonne of fish.

And every hour, another tonne is swept into the net.

In all, over 30,000 tonnes of fish

are hauled from the Sap River each year.

It's the peak catch in the Mekong,

the biggest freshwater fishery in the world.

It's so important for Cambodia

that their word for fish is also their name for money.

For Tola and his family, the monsoon has finally delivered.

The rains that were blown in from the ocean five months ago

finish their journey back where they started.

The waters of the Brahmaputra

flow into the largest river delta on Earth.

Plumes of sediment wash hundreds of kilometres out to sea, where

they seed one final monsoon bonanza.

Sperm whales.

The world's largest toothed predators, they eat squid and fish,

prey that has grown fat in nutrient-rich waters

brought by the monsoon.

But even sperm whales are dwarfed

by the largest animal that's ever lived.

This is the blue whale.

And the only place on Earth that they can be seen year round

is here, in the waters around Sri Lanka.

Waters that are fertile thanks to the monsoon...

..the destroyer and giver of life,

from tiny mosquitoes to the giants of the deep.

In this episode, the Monsoon team

filmed some of India's most dangerous animals

as they struggled to survive the deluge,

from the elephant

to the mosquito.

And each presented extraordinary challenges.

Cameraman Sandesh Kadur has been filming India's wildlife

for more than ten years.

(Did you see that?)

In the mayhem of a rising flood, anything can happen.

Run!

Now, his mission is to capture the moment the rising floods

push elephants out of their world and into ours.

This is one of the busiest highways in India.

When animals get to the highway,

this is when they meet their biggest threat.

The road borders Kaziranga National Park.

During a big flood, elephants could cross it anywhere at any time.

As a cameraman, it's really tricky to figure out where exactly to be.

What I've got to do is tap into the network,

and my network are the forest guards

and the anti-poaching camp throughout the Park.

Thank you.

There's no sign of them yet, but with the water rising fast,

it won't be long.

Right at the other end of the scale,

the team want to film an animal even more dangerous

than elephants or tigers...

..the carriers of malaria - mosquitoes, being hit by rain.

But the laws of physics make it impossible to film something

so small and fast in the wild.

So, for once in the series, a story had to be filmed

outside the monsoon region.

In the UK, the monsoon team obtained safe, disease-free specimens,

a lab for confining the insects,

and advice from an insect flight scientist whose research

helped to reveal how mosquitoes survive raindrop collision.

Imagine running and jumping off a cliff,

and a boulder, already in freefall, smacking you!

That's about what it's like.

It's incredible that they can just fly away easily.

First, they have to create droplets of just the right size and speed.

We want to simulate an environment

that is as close to natural rain as we can.

This is a lot more difficult than you'd think from the set-up.

We're just trying to get a drop of water to fall

in the same place each time,

in the same plane of focus, and even that is proving quite tricky.

A high-speed camera slows the drop 40 times, but it's not enough.

To give more falling distance on screen,

Jon turns his camera on its side.

Just filming a droplet is proving hard enough...

even without the mosquitoes!

Wow, look at that. It was not this high just yesterday.

In Kaziranga, it looks like a record flood year.

The whole Park will soon be under water.

So, probably by tomorrow morning,

I think all the animals are going to be pushed towards the highway.

Back in the lab, water is flowing steadily

and it's time at last for the mosquitoes to take centre stage.

Let's give it a go, get some out and put them on the set.

Using a tube, Andrew sucks up the cast.

But all this waiting seems to have given them stage fright.

We're not going to get any mozzies hit by raindrops

unless they fly about a bit more.

The cast are hungry for blood,

so giving them a taste of Andrew's warm human breath gets them excited.

I thought I saw something there. I just pressed the trigger.

-Oh, just missed!

-Dodged one.

-Wow.

But getting a direct hit is clearly going to take patience.

It's a 5am start for Sandesh.

There might be another herd further up the road.

We'd better hurry up.

We just found out that one herd of elephants have already crossed,

and I don't want to miss this herd.

The morning traffic is a nightmare.

And we've got some on the highway right now.

We just missed it.

Back in the lab, they're also having near misses, hundreds of them!

Got it.

-OK. Right, let's play this.

-There's a drop.

-Got you!

-Yes!

-Fantastic.

-Look at that.

-You see that there? He's probably experiencing 100Gs

when he gets hit by that drop,

so it's incredible to think he can just fly away.

And thanks to this extraordinary discovery

and a backdrop filmed in India,

a glimpse into nature as never seen before.

Sandesh is looking for another herd.

We just got information that a herd of elephants

are in the shade of these trees.

The guards think that elephants are moving up there, towards the highway.

There are elephants behind us, so we'd better be very careful,

watch our backs.

(They're crossing. They're on the edge of the road.)

(Good. They're so nervous.)

Amazing that there's not been traffic on this road

for such a long time.

And that's when they try to cross.

And then there's heavy traffic coming in.

Finally, we've got the elephants crossing the highway.

I can't believe it's taken us this long to get this shot.

It just goes to show how important it is

to be at the right place at the right time.

Next time...

The other side of the monsoon.

The rains have long gone.

Now, the winds that blow are bone dry.

But nature's response is spectacular...

..as animals and humans alike battle to overcome the drought.