Wildest Islands (2012–…): Season 1, Episode 4 - Sri Lanka: Monsoon Island - full transcript
Off India's eastern coast lies Sri Lanka (the former Ceylon), alias Monsoon island, which has a double monsoon climate. Two thirds are relatively dry plains, were largely derelict rice irrigation was the basis of ancient Buddhist kingdoms, but remains crucial to wildlife, including the largest herds of Asian elephants, a slightly larger subspecies, yet Indian relatives with tusks are imported for temple ceremonies. The largest leopard subspecies is the alpha predator, in the absence of larger felines, mainly hunting deer. More unique is the rich wildlife in the central mountains and highlands, where tropical rain is exceptionally abundant. Each has unique species, including monkeys.
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.
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.