Original subtitles

Lying like a teardrop in the Indian Ocean,

the island of Sri Lanka defies convention.

This tiny island is packed with enough wildlife

to rival a vast continent.

Nature's giants roam its sweltering plains.

In its cold, mountainous heart there are weird and wonderful creatures

found nowhere else on Earth.

This is an island steeped in history,

and a landscape carved by human hands.

From the lowlands at the mercy of two different monsoons,

to the highlands, cloaked in fog all year round.

This is Sri Lanka, the monsoon island.

Poised to six degrees above the equator,

the island of Sri Lanka is less than 75,000 square km in size.

Wind-swept coastal plains rise sharply to the central highlands,

where the peaks tower 2,000 meters

above the Indian Ocean.

For such a small country,

Sri Lanka has a complicated climate.

Unusually, two different monsoons visit this island.

Each year they roll in from the sea,

drenching the plains with weeks of torrential rain.

For the rest of the year, Sri Lanka's lowlands

endure months of drought.

But in the highlands water is plentiful all year round.

For its size, Sri Lanka has a staggering variety of wildlife,

and it's all down to its unique climate.

It's June and the dry season is fastening its grip

on the lowland plains.

It hasn't rained for weeks,

and it will be another four months before the northeast monsoon blows in.

Sri Lanka's lowlands cover more than 2/3 of the island.

And the plains are home to over 2,000 wild elephants.

This is one of the biggest populations on Earth,

and remarkable for such a small island.

With the arrival of the dry season,

finding enough food is getting more difficult.

A full grown elephant spends up to 16 hours a day grazing.

Eating the short, parched grass requires a special technique.

It's kicked and twisted from the ground,

then shaken to remove any soil.

The elephants live in close-knit family groups

under the care of an older female, the matriarch.

With many years of knowledge and experience

the matriarch knows where to find food and water in times of shortage.

Each year during the dry season herds from across Northeast Sri Lanka

make a beeline for a vast lake

known as the Minneriya Tank.

Some elephants travel hundreds of miles to reach the lake

and family groups come together to form bigger herds.

At the peak of the season,

as many as 300 gather on Minneriya's shores.

This lake is key to the survival of the island's elephants.

As the water recedes it reveals fertile ground

where fresh grass can grow.

Even after weeks without rain,

it's possible to find food around Minneriya.

The scrub forests surrounding the lake provide shelter from the sun.

Sri Lankan elephants are forest dwellers

and they've evolved for life in the shade.

For most of the year male elephants lead

a solitary existence, but here they mix together freely.

Many of the males are in season, and ready to mate.

They're pumped full of hormones,

and grapple with other bulls to assert their dominance.

For male elephants, this is a rare opportunity to socialize.

The real pull of Minneriya is a precious commodity

during any drought.

Water.

Water is essential for all animals,

but there are few that enjoy bathing as much as elephants.

Their trunks can carry up to 10 liters of water,

which is useful for showering.

Without water, the young in particular

are prone to overheating and dehydration.

Sri Lankan elephants don't have such huge ears as their African cousins,

which are the perfect way to lose body heat.

So temperature regulation can be a problem.

A dip in the lake quenches thirst

and brings cooling relief from the heat.

Even at the height of the drought,

Minneriya retains some water.

But this is no ordinary lake.

It's an ancient man-made reservoir,

built almost 2,000 years ago.

Sri Lanka's lowlands were once the center of bygone civilizations,

ruled by powerful kings and dynasties.

To capture the monsoon rains,

the kings constructed thousands of reservoirs,

known as tanks.

This ancient irrigation system provided enough water to last throughout the dry season.

Huge rice paddies were planted to feed the growing human population.

Sri Lankan's lowlands were transformed.

Many of the vast rice paddies have now been reclaimed by the jungle,

but the reservoirs still dominate the landscape of the plains,

and they govern the lives of the island's wildlife, too.

Yala lies in a remote corner on Sri Lanka's southeast coast.

For hundreds of years, this land was ruled

by a powerful dynasty.

Today Yala is a national park.

The landscape is dotted with pools, ponds, and reservoirs,

every one of them carved by human hands centuries ago.

These water holes attract a huge variety of birds.

Each year migrants from India and further afield

arrive to swell the ranks of permanent residents.

Yala is home to over 200 different species.

Many of the birds have unique adaptations that allow them to eat specific types of food.

Openbill storks feed almost exclusively

on fresh water snails.

Their distinctive open bill is the perfect tool for the job.

The gap between the upper and lower mandibles

allows the stork to use its bill like a pair of pincers.

It can delicately extract the soft meat without having to break the snail's shell.

Purple swamp hens mainly eat plants,

and they too are perfectly equipped for this habitat.

The bird's huge feet make walking on marshy ground much easier.

But its feet are also an important part of how the swamp hen finds its food.

It uses its foot to hold the plant above the water

while selecting the parts it wants to eat.

Yala's ancient reservoirs are not just a lifeline

for the birds that live here.

A year-round supply of water makes it a haven

for big herbivores like water buffalos, wild boar, and elephants.

Each morning large herds of spotted deer

gather around Yala's water holes to drink.

Like all of Sri Lanka's deer, only the males have antlers.

These are shed and regrown each year.

The deer have glands on their faces and feet

which release scent.

Stags mark their territory by leaving their scent on grasses and trees,

and by making scrapes in the ground.

As for most herbivores, the dry season is a difficult time for spotted deer.

To survive for months without rain,

many plants stop growing to conserve water,

and some lose their leaves altogether.

With less vegetation available the deer must travel further in search of food.

But Yala's ancient reservoirs ensure that

a lack of water is rarely a problem.

This allows the deer to survive in unusually high numbers here,

even at the height of the drought,

making Yala the ideal habitat for a deadly predator.

Over 40 Sri Lankan leopards stalk the park.

This is one of the highest concentrations of leopards in the world,

with up to one leopard every square kilometer.

The spotted deer are their main prey.

But the deer stay close to a useful ally.

Keeping a lookout in the trees,

grey langurs raise the alarm.

Like most cats leopards hunt by stealth,

getting as close as possible to their target

before launching a killer charge.

Given the chance the leopard will hunt the langurs, too,

though these agile monkeys make a difficult prey.

This leopard is just a youngster,

and still learning to hunt for himself.

During the day the deer and the langurs

are in their element,

but at night the leopard's ambush-hunting technique

comes into its own.

Far better for him to wait for dark.

In Sri Lanka leopards hold an unchallenged position

at the top of the food chain.

Their isolation on this island

has led to their becoming a distinct sub-species.

There are no lions or tigers on the island,

and so Sri Lanka's leopards have grown particularly big.

Fully grown males can weigh up to 80 kg.

They're the biggest leopards in the world.

Because of their size and status as the top predator,

Sri Lanka's leopards are remarkably confident.

Elsewhere it's unusual to see a leopard

out in the open in broad daylight.

But even in Yala, mothers with young cubs

are much more cautious.

It's extremely rare to see them.

Hidden deep within the thick scrub

is her kill from last night,

the carcass of a grey langur.

For some animals the arrival of the dry season

heralds a time of plenty.

As Yala's water holes begin to shrink,

fish and amphibians are trapped within ever-smaller pools.

There are fewer places to hide

and there's no escaping the watchful gaze of a purple heron.

With plenty of food available,

this is a good time of year to start a family.

For many animals, June brings the mating season.

When white-throated kingfishers are courting,

they share gifts of food.

But this male seems reluctant to hand over the frog he's caught.

Eventually the female simply catches her own.

There are bigger predators fishing in Yala's water holes.

Mugger crocodiles cruise the pools,

making the most of the bounty of fish now trapped within their confines.

Nowhere else in the Indian sub-continent

supports these huge reptiles in such great numbers

as the tiny island of Sri Lanka.

The crocodiles eat mainly fish,

but larger males will also prey on animals they can seize from the water's edge.

The muggers are unlikely to attack one of the biggest mammals on Earth,

although a water buffalo and her calf remain on the alert.

But by late morning the crocodiles are no longer interested in food.

For them too, June is the start of the mating season.

Confined within small pools,

the muggers are forced to become much more sociable.

Males compete for dominance by thrashing the surface of the water.

Having trounced his rivals,

the victor wins access to the female.

The crocodiles aren't the only ones intent on courtship.

Bee-eaters nest during the dry season,

so there's no risk of their burrow being flooded by rain water.

The tunnel will extend up to two meters underground,

where the eggs will be safe from predators.

The work gives the birds a healthy appetite.

As their name suggests,

bee-eaters specialize in catching bees.

Each pair shares a favorite perch

from which they go hunting.

Before eating the bee, the bird removes the sting

and wipes off the venom.

These birds are prolific hunters,

sometimes catching several hundred insects a day.

The ancient reservoirs are not the only legacy

of Sri Lanka's human history that continues to provide a safe haven for wildlife.

A thousand years ago, this sprawling metropolis

was Sri Lanka's capitol.

Lying in the northeastern lowlands,

ruins are all that remain of the city of Pollonaruwa.

In its glory days Pollonaruwa saw the rise and fall of human dynasties.

Nowadays this ancient city is overrun by monkeys.

Hundreds of toque macaques battle for territory amongst the ruins.

The macaques live in big groups of up to 40 animals.

They follow a strict hierarchy under the leadership of an alpha male.

Each macaque has a distinct personality and hairstyle.

Females have colorful red faces.

The troop relies on the knowledge of older females to lead them to food.

In this case, a flowering tree.

Macaques can eat virtually anything,

but during the dry season good food gets harder to find.

Dead leaves may hide insects, tree nuts, and fallen fruit.

Lower-ranking monkeys must wait for those of higher status to eat first.

This is a fiercely competitive world.

Monkeys that ignore the pecking order

don't go unnoticed by the alpha male.

Toque macaques have cheek pouches

which contain a special enzyme to help them digest food.

The pouches are also a good place to hide food from rivals.

Even this doesn't always prevent a high-ranking monkey

from trying to steal their entitlement.

If the monkey of lower status resists too strongly,

she'll be reprimanded.

After eating young males engage in boisterous bouts of play,

oblivious to their auspicious surroundings.

Once fully grown these youngsters will have to leave the group and go it alone.

Good fighting skills may one day mean

the difference between life and death.

For toque macaques, the greatest threat

comes from other toque macaques.

Fully grown males are twice as big as females

and have huge canine teeth.

For males the hierarchy controls not just access to food,

but also access to mates.

The alpha male has fathered most of the youngsters in this troop.

In toque macaque society,

it pays to make friends rather than enemies.

The monkeys are left to roam the ruins of Pollonaruwa,

even though it's one of Sri Lanka's most important Buddhist monuments.

This island is steeped in over 2,000 years

of Buddhist tradition.

Buddhism teaches the sanctity of all living things.

No animals should be harmed unnecessarily.

Over the centuries, Buddhism has played its part

in conserving and protecting Sri Lanka's wild animals,

even dangerous ones.

The bodhi tree is sacred in Buddhist belief,

and these trees are grown in many of the island's temples.

Flames lit as offerings attract insects to the tree,

which in turn, attract small reptiles.

This brings bigger hunters.

Sri Lanka has one of the highest incidences of death by snake bite of any country on Earth.

A bite from this spectacled cobra can kill within minutes.

But because Buddhism teaches respect for all living creatures,

poisonous snakes aren't just tolerated,

they're actually respected by many Sri Lankans.

No animal is as intimately connected

to the history and culture of Sri Lanka as the elephant.

Centuries ago these huge mammals

were used to build the foundations of great cities,

and to carve out their reservoirs.

To this day, elephants still play

an important role in island life.

Few Buddhist festivals are complete without a retinue of elephants.

For religious ceremonies,

it's important the elephants have tusks.

In Sri Lanka, less than 10% of male elephants are tuskers,

so temple elephants are usually imported

from elsewhere in Asia.

A wild Sri Lankan tusker is a rare sight.

In the south of the island the hills rise out of the plains

to form Sri Lanka's mountainous heart.

The core of the central highlands is a high plateau

running north to south for around 60 km.

The peaks are shrouded in a swiftly-moving blanket of cloud.

The cloud forests feel a world away

from the sweltering heat of the plains.

Though Sri Lanka's lowlands are in the grip of the dry season,

up here there's no shortage of water all year round.

The lichens, mosses, and ferns that cloak every tree act like sponges.

In a process known as fog stripping,

they absorb moisture from the clouds.

Gradually this is released into the many waterways

that criss-cross the highlands.

Three major rivers have their origins here,

delivering precious water down to the arid plains.

Just like the ancient reservoirs,

Sri Lanka's cold heart plays its part

in sustaining the whole island through periods of drought.

The constant supply of water means that the central highlands

can support an astonishing variety of different animals.

Many are found nowhere else on Earth.

These forests shelter a rare primate

that's found only in Sri Lanka,

the purple-faced langur.

There are purple-faced langurs in the lowlands, too,

but those in the highlands are a distinct sub-species.

They're specially adapted to deal with the extreme weather.

Their thick, shaggy coats have earned them the nickname, the bear monkey.

Langurs are leaf-eaters,

and they spend a lot of time feeding.

Leaves are selected with care and often with considerable effort.

Younger leaves contain more protein

and are easier to digest.

It may be 30° C down on the plains,

but up here the nighttime temperatures

can fall below zero.

The herds of sambar deer that graze the windswept plateau

have thick fur to protect them from the cold.

They're the only species of deer on the island

that can survive the cold conditions of the central highlands.

Though they live in the heart of a tropical island,

the animals in the highlands have had to adapt to the cold.

Even in the undergrowth, the cloud forest harbors

many unique animals and plants.

Half the reptiles that live here are found nowhere else.

At less than 10 cm long,

the Sri Lankan pygmy lizard lives up to its name.

These tiny lizards are also well-adapted

to cope with the cold.

Eggs are hatched inside the body of the parent

to protect them from the temperatures outside.

Unlike almost all other reptiles,

the Sri Lankan pygmy lizard gives birth to live young.

The highlands may be cold but the constant supply of water drives diversity,

just like in a tropical rainforest.

The male rhino-horned lizard bears a horn on its nose

that can grow almost half an inch long.

The exact purpose of this strange growth remains a mystery.

The female rhino-horned lizard also has a horn,

but it's considerably smaller.

Sri Lanka's highlands remain relatively unexplored.

Little is known about some of the unusual animals that live here.

Out on the plateau,

even within one small rhododendron bush,

there's a unique community of animals

that are found nowhere else.

Its flowers provide sanctuary for a black-cheeked lizard.

On a neighboring bush there's a rival male.

Black-cheeked lizards are fiercely territorial.

Head nodding serves as a warning to stay away.

The Ceylon white-eye is a common sight in the rhododendrons.

But like so many of the animals here,

these birds are only found in the highlands.

Each time the white-eye dips its head to feed on nectar,

it collects a fine coat of pollen.

The bird transfers this pollen from plant to plant

and may well play a part in helping the rhododendrons to reproduce.

If so, it's helping to preserve yet another unique species.

The rhododendron is itself a sub-species that only grows in the highlands.

Though they cover less than a third of the island,

the highlands are what makes Sri Lanka so special.

A staggering number of plants and animals in the highlands

are found nowhere else on Earth.

Half the tree species are found only in the cloud forest,

and over a third of the island's flowering plants

grow only in the mountains.

These cold, wet highlands make Sri Lanka

one of the most species-rich islands on the planet.

By late September, the drought in the lowlands

is reaching its peak.

It's almost eight months since the last rain fell in Yala.

At this time of year a good sunscreen

is more important than ever.

Applying a layer of dust helps protect against the sun

and rids the skin of any parasites.

The water in the ancient reservoirs is greatly reduced.

Flocks of painted storks use their feet

to stir up any fish.

The fish are easy to catch but there's lots of competition,

and it's not just from the other birds.

The storks startle fish straight into the crocodile's jaws.

This may be why the storks can hunt so close

to this huge predator without fear.

In the sweltering heat spotted deer seek out the small pools of water

that remain in Yala's rocky outcrops.

These tiny oases were formed from rainwater

during the last monsoon.

Some are deep enough to persist throughout the year.

The deer are nervous, and with good reason.

These outcrops are the daytime haunts

of Yala's top predator.

The rocks provide a cool sanctuary in the heat of the day,

and a high vantage-point to observe the comings and goings of their prey.

As the sun begins to set,

Yala's leopards start to stir.

It's at night that they do most of their hunting.

During the night the leopard has made a kill.

Weakened by the drought,

many spotted deer perish at this time of year.

But relief is in sight.

In October, the prevailing wind changes direction.

The winds collect moist air from the Indian Ocean

and drive it toward Sri Lanka's lowlands.

The monsoon has finally arrived.

Within days, the plains are awash.

Over the next four months,

parts of the lowlands will receive nearly 200 cm of rain.

Every precious drop is captured in Sri Lanka's ancient man-made reservoirs.

The rain brings new growth and abundant food

for the lowland's herbivores.

In the ancient city of Pollonaruwa,

the forest is transformed.

The toque macaques easily adjust to their new environment.

For most of the year plants and fruits form their staple diet.

But the more experienced monkeys have learned

that the flush of new vegetation brings an annual protein-rich feast.

Caterpillars.

For centuries all life on Sri Lanka has centered

on one precious resource, water.

Bygone civilizations built a network of ancient reservoirs

that capture the monsoon rains

and sustain the lowlands through months of drought.

In the island's cold, mountainous heart,

there's plenty of water all year round,

and the highlands are home to an extraordinary number of animals that are found nowhere else.

The complicated climate of this tiny island

is what makes Sri Lanka one of the most species-rich places on Earth.