Earth's Tropical Islands (2020): Season 1, Episode 1 - Madagascar - full transcript
Exploring the unique wildlife of Madagascar, the oldest island on earth.
Far away, cut off by vast oceans...
...lie Earth's tropical islands.
Home to remarkable animal
castaways...
...that have evolved in isolation.
And human cultures that have adapted
in extraordinary ways.
From the jungles of Borneo with
their staggering wild diversity...
...to Hawaii,
the most remote island chain,
colonised by only the hardiest
pioneers.
And Madagascar,
the oldest island of all...
...where time has given rise to
thousands of unique species.
These tropical islands
have developed into astonishing
and unique worlds.
Cradling precious life found nowhere
else on Earth.
In the tropical
waters of the Indian Ocean...
...lies the oldest island on Earth.
Madagascar.
Isolated for longer than any other
island.
Life has had time to evolve in the
most surprising ways.
With over 15,000 species found
nowhere else.
Madagascar boasts more unique plants
and animals
than any other island on the planet.
Madagascar was formed nearly
90 million years ago.
Giant landmass, known as Gondwana,
broke apart.
As India split from Africa,
Madagascar was cast adrift.
It's a vast island
almost the size of France.
And home to an astonishing array of
ancient habitats.
At its heart lie the highlands,
an immense mountainous spine that
determines the island's climate.
Warm, wet air blows in off the
Indian Ocean,
drenching the east of Madagascar
with rain.
But the mountains block this rain
from reaching the west,
creating a great expanse of desert.
This arid landscape stretches
halfway up the west coast.
It was here,
around 55 million years ago,
that a few animal castaways
washed ashore.
Having somehow survived the 300-mile
crossing from Africa.
One of the very first mammals
to arrive
was an ancient species of primate.
And their direct descendants still
live here in the desert today.
Ring-tailed lemurs.
It's dawn.
And a family of nine soak up the
warmth of the early morning sun,
preserving vital energy for the day
ahead.
This young lemur is just six
months old...
...and born into the harshest habitat
on the island.
Known as the Spiny Forest.
Tiny leathery leaves provide
little nourishment.
The troop spends up to eight hours
a day
scouring the desert for food.
Tackling even the most
hostile vegetation.
The sticky sap that oozes out of
Euphorbia plants
can be caustic,
and burn human flesh.
Yet ringtails are resistant
to their corrosive powers.
Euphorbia sap is also rich in fats.
Much-needed fuel that will help this
young lemur survive
this inhospitable desert.
Ringtails are just one of the many
species of lemur.
These primates are found only on
Madagascar.
Their ancient ancestors gradually
spread east across the island.
Adapting to each of Madagascar's
varied habitats.
They now number more than 100
different species.
Humans are thought to have arrived
on this island
just a few thousand years ago.
First from Asia,
and then from Africa,
they settled on the coast.
Pushing inland, those in the west
faced the hostile desert.
Just 20 miles from the coastline
lies the village of Ampotaka.
It's the dry season.
Temperatures often reach
40 degrees Celsius.
It hasn't rained for ten months now.
With their nearest water supply over
40 miles away,
life is a daily struggle.
The remains of this year's melon
harvest
provide just enough water to cook
with.
At 62, Adolphe has lived through
the driest of years.
IN OWN LANGUAGE:
Today, Adolphe is joined
by his son Leris...
...to visit the secret to their
survival.
The baobab.
Known as "The Tree Of Life."
They can live for over 1,000 years.
Growing up to 30 metres high,
baobabs can hold vast quantities of
water in their immense trunks...
...and can survive for years without
a single drop of rain.
For Adolphe, this baobab provides a
lifeline.
By hollowing out the soft trunk,
they created a tank,
which they could fill with water
during the brief rainy season.
This living reservoir can store
thousands of litres of water.
But this dry season has lasted so
long that the tree is already empty.
Still, it's an important opportunity
to trim back the growing bark,
maintaining the tank's size ready
for the rain
they hope will come soon.
This tank may have run dry.
But Adolphe inherited seven of these
wells from his father.
Only one still holds any water.
With only enough water to last a few
more weeks,
it's a worrying time for Adolphe and
his family.
Survival in this desert depends on
the arrival of the rains.
On the forest floor, there are signs
that the weather is changing.
Tiny Labord's chameleons, only three
centimetres long, begin to hatch.
They live for only four months.
The shortest lifespan of any
land vertebrate.
For this young male,
it's a race against time.
In the dry season, there is
little food.
But his hatching is perfectly timed.
DISTANT RUMBLING
THUNDER RUMBLING
It's the start of the rainy season.
The parched landscape is transformed
into a flush of green.
Just what this growing chameleon
needs.
As his eyes can move
independently...
...he can spot a meal in any
direction...
...and, by locking both eyes onto a
target, judge distance.
With deadly accuracy.
With so much food on offer,
the male Labord's chameleon can grow
five times his size
in just two months.
Transforming into an adult male with
an eye-catching horn.
A female approaches.
But the male has a rival.
With such short lives,
there's fierce competition for a
chance to mate.
HISSING
With his rival out of the way,
he hasn't got long to take this
opportunity.
After just four months,
this male has succeeded in securing
the next generation.
The female will lay her fertilised
eggs underground before she dies.
And as the dry season returns,
not a single adult Labord's
chameleon...
...will be left alive.
Arid regions cover more than half of
western Madagascar.
Including one of its most extreme
habitats.
The Grand Tsingy.
More than 500 square miles of sharp
limestone pinnacles.
Eroded by rainfall over millions
of years.
Its deep, shaded ravines retain
moisture.
Allowing small pockets of forest to
grow.
And providing an oasis...
...for an extraordinary lemur.
Decken's sifaka.
This youngster is three months
old...
...and already practising the vital
skill of leaping.
No one cluster of trees is
large enough
to sustain a whole family
of hungry sifakas.
This mother and son need to seek out
another pocket of vegetation.
Possibly hundreds of metres away.
They must run a deadly gauntlet.
These limestone shards stand more
than 100 metres tall...
...and are sharp enough
to shred human skin.
But sifakas have thick,
rubbery footpads,
and spring-like legs that can leap
nine metres in a single bound.
These lemurs have evolved
into blade runners.
Safely across, mother and son claim
their reward.
The fresh, juicy leaves they need to
survive.
Over millions of years of evolution,
the Decken's sifaka has overcome the
extreme conditions
of the Grand Tsingy.
But as Madagascar's lemurs continued
to spread east across the island,
they eventually encountered an
immense barrier.
Over 100 miles inland,
the Highlands.
It's these towering peaks that
divide Madagascar's climate.
Rising over 2,000 metres,
they capture the full force
of the seasonal rain blowing in from
the east.
Millions of years of rainfall have
carved out fertile valleys,
perfect for growing rice.
A staple food of Madagascar's
people.
Just a few thousand years ago,
settlers from Asia brought the
skills to turn even
the steepest mountains into terraced
rice paddies.
Today, subsistence farmers produce
more than one million tonnes
of rice here every year.
MAN AND WOMAN SPEAKING
Marivelo owns four paddy fields.
Providing just enough rice for her
family of ten.
It's January,
the height of the rainy season.
And the most important time for any
rice farmer.
Each kilogram of rice needs more
than 2,000 litres of water to grow.
With rainwater flooding
the rice paddies,
Marivelo must prepare them
for planting.
But instead of using a plough, she
uses her most prized possession.
Originally from Asia,
these are zebu cattle.
MEN WHISTLING
The stampeding hooves churn up the
soil.
It may be dangerous work,
but it's an ancient practice unique
to Madagascar.
And brings the whole
community together.
With the soil prepared, it's time to
get planting.
To make the most of the peak rains,
Marivelo and her daughters need to
work fast.
THEY CHEER
They're precision planters.
Every blade is 20 cm apart,
ensuring maximum yield.
ALL CHEERING
In three months' time, the rice crop
should be ready for harvest,
providing Marivelo and her family with
plenty of food for the year ahead.
Unless the crop is struck by one
of the most destructive creatures on
the planet.
Locusts.
They're normally solitary insects.
But when there's an
abundance of crops,
their numbers can reach plague
proportions.
These flightless hoppers can form
armies over half a mile long.
But they have only just begun
on their path of destruction.
At five weeks old,
they morph into
fully-fledged adults...
...and can take to the air
in their billions.
A swarm this size may only appear
once in a decade in Madagascar.
Travelling over 50 miles a day,
they can devour
40,000 tonnes of vegetation...
...including the farmers'
precious rice crops.
On reaching the highlands,
a plague is finally stopped
by the heavy mountain rains.
Wet wings prevent
the locusts from flying,
until, eventually,
the swarm runs out of food,
and dies.
To the east of the highlands lies
a completely different world.
With warm, humid air blowing
in off the Indian Ocean, it receives
ten times the rainfall of the west,
creating lush rainforests.
When Madagascar's ancient castaways
eventually reached these
eastern forests, they flourished.
Over time, creatures
evolved in extraordinary ways...
...colonising every
corner of the jungle.
Today, two thirds of the island's
plants and animals are found here.
The forest floor is home to
another ancient castaway,
originally from Africa.
It may look like a hedgehog,
but this is a tenrec,
found only on Madagascar.
They give birth to more babies
than any other mammal.
As many as 32
in a single litter.
Like lemurs, they've evolved
into a wide variety of species...
...each adapting in remarkable ways
to their forest home.
At just four weeks old,
these streaked tenrecs
are almost fully grown...
...eagerly sniffing out a meal
with their flexible snouts.
To fuel their high metabolism,
they can eat over 30 worms a day.
And they quickly disperse.
A deadly Madagascan ground boa.
The mother tenrec senses danger
and quickly sounds the alarm...
...by rubbing together modified
spines on her back.
The high pitched sounds cut through
the clamour of the forest
and the youngsters scurry
back to her.
SCRAPING
This is a unique
form of communication
used by no other mammal
on the planet,
a bizarre adaptation to
survive in these crowded forests.
At night, an even stranger
cast of creatures emerges.
The aptly-named pelican spider.
No larger than a grain of rice,
he has a formidable set of jaws.
This male is on the hunt
for his next meal.
Using his extra-long front legs,
he searches for signs of life.
A silk thread...
...is the perfect lead.
A female orb web spider.
But she's protected
by her sticky web.
What to do?
Fortunately, the pelican spider
has had millions of years
to fine-tune its technique.
Mimicking the movements of a fly
caught in her web,
he lures her towards him.
He uses his massive
jaws to keep her at a distance
and avoid her lethal bite,
then paralyses her with his own
powerful venom,
before tucking in.
The intense competition for food
in Madagascar's crowded rainforest
has pushed its inhabitants to
evolve in the most extreme ways...
...and the lemurs are no exception.
This is an aye-aye,
filmed in a special enclosure.
Her favourite food is insect larvae,
which can only be found
deep inside the branches of trees.
But the aye-aye has perfected
a truly remarkable
way of getting to them.
It's a technique that's thought
to take four years to master.
Using her nine centimetre-long
middle finger,
she taps to hear where
the branch is hollow.
Then she gnaws
away at the protective bark...
...before deploying her
super-sized finger
to fish out any juicy grubs.
Madagascar's unique wildlife has had
millions of years to slowly evolve.
But in the last few thousand
years, the pace of life
has increased rapidly,
with deadly consequences...
...as revealed by a recent discovery
in Madagascar's most remote desert.
This pool is a portal to
a previously unexplored world.
In 2015, divers first ventured into
this network of flooded passages.
50 metres below the surface,
they entered a truly magical
underworld...
...discovering more than 11 km
of connected tunnels...
...and some of the largest
underwater chambers in the world.
But what they found
inside these caves
was even more remarkable...
...a vast graveyard...
...the preserved
remains of mysterious creatures...
...four metre-long
horned crocodiles...
...puma-like predators,
and ancient pygmy hippos.
But perhaps most impressive of
all...
...the skulls of giant lemurs that
grew to the size of a gorilla.
All long gone.
Their extinction coincided
with the most disruptive
change in Madagascar's
long history...
...the arrival of people.
And today, our impact on the island
is greater than ever before.
Madagascar's forests
are disappearing faster than
any other tropical country, cleared
largely for subsistence farming.
As little as 20% of the
island's original forest remains.
And the impact on Madagascar's
unique wildlife
has been devastating.
95% of lemurs are now
threatened with extinction...
...making them the most vulnerable
group of mammals in the world.
One of the most endangered is
found in the east of the island...
...the greater bamboo lemur.
Like all lemurs,
they're highly-specialised.
Bamboo makes up nearly 95%
of their diet,
despite being packed
with deadly cyanide.
Every day, a single lemur
can eat enough poison
to kill five humans.
They have evolved to
withstand its toxic effects,
keeping these thickets
all to themselves.
But now, their unique adaptation
has left them trapped here...
...unable to live anywhere else.
As their bamboo
forests are cleared for agriculture,
these lemurs are left
with nowhere to live,
and little to eat.
The greater bamboo lemur was once
thought to have gone extinct.
But thanks to a recent
concerted effort to protect them,
there is now a glimmer of hope.
In the last year, this group
had a record number of babies,
adding 72 to their total
population of 400.
The island of Madagascar has
reached a critical point.
And only with intensive conservation
efforts will its remarkable,
and unique wildlife
survive into the future.
Filming the critically endangered
greater bamboo lemur took
the crew to one of the most remote
regions of eastern Madagascar,
only accessible by a challenging
two-day drive.
The road is deteriorating.
The wooden bridges
are getting narrower.
The roads are worse
than everyone expected.
We appear to have already got
one of our vehicles stuck.
Finally, they reach Vohitrarivo,
a village close to one of the last
known refuges of this rare lemur.
Over the next two weeks, the crew
will be led by primatologist
Delphine Roullet, who came here
ten years ago on an urgent
mission to save the bamboo lemurs.
With the help of her organisation,
around 400 lemurs now live
in these pockets of bamboo forest,
but they're spread over a vast area.
Hopefully, we're nearly there
and can stop climbing up the hills.
To help narrow their search,
they head into the bush to meet
local lemur researcher Noret.
Ahead of the shoot,
he sets up camera traps to hopefully
establish the lemurs' whereabouts.
Let's see.
Oh, what's that?
There is one!
It's a good sign.
A troupe of bamboo lemurs were
in the area just a few days ago.
Oh, look, just here.
Yeah, completely dark.
But the lemurs can travel through
these thickets with ease, so it will
take all of Noret and Delphine's
skills to track them down.
I think Noret can see them.
I can't see them.
You can see a dark spot,
just straight.
They may have spotted them
in the distance,
but the lemurs are leading the crew
into even thicker vegetation.
I'm getting entangled in sticky
grass, and it's dense here.
No way this is going to work.
After nearly a week of tracking,
cameraman Justin is finally
getting closer.
But getting a clear shot of them
remains a significant challenge.
Yeah, right now there's two
just below us, but we can't film it.
There's too much vegetation.
Their wild lemur chase eventually
takes them to the
edge of the bamboo forest
and into the farmland beyond.
Noret and the crew check in with
the locals to get the latest
information on any
lemur sightings...
SPEAKS LOCAL LANGUAGE
...only to stumble upon the lemurs
right in front of them.
So, we've just turned
up to find them crossing this
section of rice paddy, between one
part of bamboo forest and another.
With much of their bamboo forest
cleared for agriculture,
the lemurs are forced to
venture into the open.
Sort of surprising to find them
here, because they really don't
like dogs, and the villagers keep
dogs, but so far they seem relaxed.
Although bamboo
is their preferred diet,
the lemurs will sometimes resort
to raiding rice crops.
In the past, this has led to
conflict with the locals,
but Delphine's project
has changed all that.
Villagers like Noret are
trained as lemur guardians.
They help study the troupes
and marshal them
off farming land before
any damage is caused.
Justin is still trying
to get his shot...
...when conditions take
a turn for the worse.
THUNDERCLAP
The rain makes filming quite
difficult, and it makes it
really hard to keep everything
and everybody dry, and not muddy.
So, at the moment the lemurs
are keeping their heads down,
so we're doing the same.
The lemurs may be close by,
but the rain continues
for four whole days.
We're just having to sit out
and hope they start moving
somewhere we can see them.
That frustration of having what you
want, but not being able to see it.
But all this rain brings about a
surprising change to their fortunes.
The rain triggers a flush of
growth in the bamboo shoots,
the lemurs' favourite food
and draws them out into the open.
So, it's been raining
nonstop for five days now
and I feel pretty
wet from top to bottom.
We can see six of them
stuffing their faces with bamboo,
which is a lovely sight to see.
I'm really happy to be
here, despite the rain.
It's amazing.
And there is an added bonus.
The mother bamboo lemurs have
timed their births to coincide with
the arrival of fresh bamboo
and the crew can film one of the
first newborns of the season.
Oh, it's so good to see the babies!
Cute!
Took a long time to get to this
point of actually having them
in front of us, so we can film them.
It's just great to have
moments like this.
These rare and intimate
portraits of baby lemurs is
the start of a record breeding year.
Over the following two months,
72 babies are born.
It's a huge boost to this
endangered population.
But their future
rests in the hands of the next
generation of lemur guardians.
A vital part of Noret
and Delphine's work is
sharing their knowledge with those
living side by side with the lemurs.
Thanks to Delphine, Noret,
and their dedicated team, one
of Madagascar's rarest lemurs
is now back
from the brink of extinction.
Next time, Borneo...
...home to a staggering
variety of habitats.
From its bustling coral reefs
and ancient rainforests,
to its mountainous heart...
...Borneo holds possibly the greatest
diversity of life...
...of any island.
...lie Earth's tropical islands.
Home to remarkable animal
castaways...
...that have evolved in isolation.
And human cultures that have adapted
in extraordinary ways.
From the jungles of Borneo with
their staggering wild diversity...
...to Hawaii,
the most remote island chain,
colonised by only the hardiest
pioneers.
And Madagascar,
the oldest island of all...
...where time has given rise to
thousands of unique species.
These tropical islands
have developed into astonishing
and unique worlds.
Cradling precious life found nowhere
else on Earth.
In the tropical
waters of the Indian Ocean...
...lies the oldest island on Earth.
Madagascar.
Isolated for longer than any other
island.
Life has had time to evolve in the
most surprising ways.
With over 15,000 species found
nowhere else.
Madagascar boasts more unique plants
and animals
than any other island on the planet.
Madagascar was formed nearly
90 million years ago.
Giant landmass, known as Gondwana,
broke apart.
As India split from Africa,
Madagascar was cast adrift.
It's a vast island
almost the size of France.
And home to an astonishing array of
ancient habitats.
At its heart lie the highlands,
an immense mountainous spine that
determines the island's climate.
Warm, wet air blows in off the
Indian Ocean,
drenching the east of Madagascar
with rain.
But the mountains block this rain
from reaching the west,
creating a great expanse of desert.
This arid landscape stretches
halfway up the west coast.
It was here,
around 55 million years ago,
that a few animal castaways
washed ashore.
Having somehow survived the 300-mile
crossing from Africa.
One of the very first mammals
to arrive
was an ancient species of primate.
And their direct descendants still
live here in the desert today.
Ring-tailed lemurs.
It's dawn.
And a family of nine soak up the
warmth of the early morning sun,
preserving vital energy for the day
ahead.
This young lemur is just six
months old...
...and born into the harshest habitat
on the island.
Known as the Spiny Forest.
Tiny leathery leaves provide
little nourishment.
The troop spends up to eight hours
a day
scouring the desert for food.
Tackling even the most
hostile vegetation.
The sticky sap that oozes out of
Euphorbia plants
can be caustic,
and burn human flesh.
Yet ringtails are resistant
to their corrosive powers.
Euphorbia sap is also rich in fats.
Much-needed fuel that will help this
young lemur survive
this inhospitable desert.
Ringtails are just one of the many
species of lemur.
These primates are found only on
Madagascar.
Their ancient ancestors gradually
spread east across the island.
Adapting to each of Madagascar's
varied habitats.
They now number more than 100
different species.
Humans are thought to have arrived
on this island
just a few thousand years ago.
First from Asia,
and then from Africa,
they settled on the coast.
Pushing inland, those in the west
faced the hostile desert.
Just 20 miles from the coastline
lies the village of Ampotaka.
It's the dry season.
Temperatures often reach
40 degrees Celsius.
It hasn't rained for ten months now.
With their nearest water supply over
40 miles away,
life is a daily struggle.
The remains of this year's melon
harvest
provide just enough water to cook
with.
At 62, Adolphe has lived through
the driest of years.
IN OWN LANGUAGE:
Today, Adolphe is joined
by his son Leris...
...to visit the secret to their
survival.
The baobab.
Known as "The Tree Of Life."
They can live for over 1,000 years.
Growing up to 30 metres high,
baobabs can hold vast quantities of
water in their immense trunks...
...and can survive for years without
a single drop of rain.
For Adolphe, this baobab provides a
lifeline.
By hollowing out the soft trunk,
they created a tank,
which they could fill with water
during the brief rainy season.
This living reservoir can store
thousands of litres of water.
But this dry season has lasted so
long that the tree is already empty.
Still, it's an important opportunity
to trim back the growing bark,
maintaining the tank's size ready
for the rain
they hope will come soon.
This tank may have run dry.
But Adolphe inherited seven of these
wells from his father.
Only one still holds any water.
With only enough water to last a few
more weeks,
it's a worrying time for Adolphe and
his family.
Survival in this desert depends on
the arrival of the rains.
On the forest floor, there are signs
that the weather is changing.
Tiny Labord's chameleons, only three
centimetres long, begin to hatch.
They live for only four months.
The shortest lifespan of any
land vertebrate.
For this young male,
it's a race against time.
In the dry season, there is
little food.
But his hatching is perfectly timed.
DISTANT RUMBLING
THUNDER RUMBLING
It's the start of the rainy season.
The parched landscape is transformed
into a flush of green.
Just what this growing chameleon
needs.
As his eyes can move
independently...
...he can spot a meal in any
direction...
...and, by locking both eyes onto a
target, judge distance.
With deadly accuracy.
With so much food on offer,
the male Labord's chameleon can grow
five times his size
in just two months.
Transforming into an adult male with
an eye-catching horn.
A female approaches.
But the male has a rival.
With such short lives,
there's fierce competition for a
chance to mate.
HISSING
With his rival out of the way,
he hasn't got long to take this
opportunity.
After just four months,
this male has succeeded in securing
the next generation.
The female will lay her fertilised
eggs underground before she dies.
And as the dry season returns,
not a single adult Labord's
chameleon...
...will be left alive.
Arid regions cover more than half of
western Madagascar.
Including one of its most extreme
habitats.
The Grand Tsingy.
More than 500 square miles of sharp
limestone pinnacles.
Eroded by rainfall over millions
of years.
Its deep, shaded ravines retain
moisture.
Allowing small pockets of forest to
grow.
And providing an oasis...
...for an extraordinary lemur.
Decken's sifaka.
This youngster is three months
old...
...and already practising the vital
skill of leaping.
No one cluster of trees is
large enough
to sustain a whole family
of hungry sifakas.
This mother and son need to seek out
another pocket of vegetation.
Possibly hundreds of metres away.
They must run a deadly gauntlet.
These limestone shards stand more
than 100 metres tall...
...and are sharp enough
to shred human skin.
But sifakas have thick,
rubbery footpads,
and spring-like legs that can leap
nine metres in a single bound.
These lemurs have evolved
into blade runners.
Safely across, mother and son claim
their reward.
The fresh, juicy leaves they need to
survive.
Over millions of years of evolution,
the Decken's sifaka has overcome the
extreme conditions
of the Grand Tsingy.
But as Madagascar's lemurs continued
to spread east across the island,
they eventually encountered an
immense barrier.
Over 100 miles inland,
the Highlands.
It's these towering peaks that
divide Madagascar's climate.
Rising over 2,000 metres,
they capture the full force
of the seasonal rain blowing in from
the east.
Millions of years of rainfall have
carved out fertile valleys,
perfect for growing rice.
A staple food of Madagascar's
people.
Just a few thousand years ago,
settlers from Asia brought the
skills to turn even
the steepest mountains into terraced
rice paddies.
Today, subsistence farmers produce
more than one million tonnes
of rice here every year.
MAN AND WOMAN SPEAKING
Marivelo owns four paddy fields.
Providing just enough rice for her
family of ten.
It's January,
the height of the rainy season.
And the most important time for any
rice farmer.
Each kilogram of rice needs more
than 2,000 litres of water to grow.
With rainwater flooding
the rice paddies,
Marivelo must prepare them
for planting.
But instead of using a plough, she
uses her most prized possession.
Originally from Asia,
these are zebu cattle.
MEN WHISTLING
The stampeding hooves churn up the
soil.
It may be dangerous work,
but it's an ancient practice unique
to Madagascar.
And brings the whole
community together.
With the soil prepared, it's time to
get planting.
To make the most of the peak rains,
Marivelo and her daughters need to
work fast.
THEY CHEER
They're precision planters.
Every blade is 20 cm apart,
ensuring maximum yield.
ALL CHEERING
In three months' time, the rice crop
should be ready for harvest,
providing Marivelo and her family with
plenty of food for the year ahead.
Unless the crop is struck by one
of the most destructive creatures on
the planet.
Locusts.
They're normally solitary insects.
But when there's an
abundance of crops,
their numbers can reach plague
proportions.
These flightless hoppers can form
armies over half a mile long.
But they have only just begun
on their path of destruction.
At five weeks old,
they morph into
fully-fledged adults...
...and can take to the air
in their billions.
A swarm this size may only appear
once in a decade in Madagascar.
Travelling over 50 miles a day,
they can devour
40,000 tonnes of vegetation...
...including the farmers'
precious rice crops.
On reaching the highlands,
a plague is finally stopped
by the heavy mountain rains.
Wet wings prevent
the locusts from flying,
until, eventually,
the swarm runs out of food,
and dies.
To the east of the highlands lies
a completely different world.
With warm, humid air blowing
in off the Indian Ocean, it receives
ten times the rainfall of the west,
creating lush rainforests.
When Madagascar's ancient castaways
eventually reached these
eastern forests, they flourished.
Over time, creatures
evolved in extraordinary ways...
...colonising every
corner of the jungle.
Today, two thirds of the island's
plants and animals are found here.
The forest floor is home to
another ancient castaway,
originally from Africa.
It may look like a hedgehog,
but this is a tenrec,
found only on Madagascar.
They give birth to more babies
than any other mammal.
As many as 32
in a single litter.
Like lemurs, they've evolved
into a wide variety of species...
...each adapting in remarkable ways
to their forest home.
At just four weeks old,
these streaked tenrecs
are almost fully grown...
...eagerly sniffing out a meal
with their flexible snouts.
To fuel their high metabolism,
they can eat over 30 worms a day.
And they quickly disperse.
A deadly Madagascan ground boa.
The mother tenrec senses danger
and quickly sounds the alarm...
...by rubbing together modified
spines on her back.
The high pitched sounds cut through
the clamour of the forest
and the youngsters scurry
back to her.
SCRAPING
This is a unique
form of communication
used by no other mammal
on the planet,
a bizarre adaptation to
survive in these crowded forests.
At night, an even stranger
cast of creatures emerges.
The aptly-named pelican spider.
No larger than a grain of rice,
he has a formidable set of jaws.
This male is on the hunt
for his next meal.
Using his extra-long front legs,
he searches for signs of life.
A silk thread...
...is the perfect lead.
A female orb web spider.
But she's protected
by her sticky web.
What to do?
Fortunately, the pelican spider
has had millions of years
to fine-tune its technique.
Mimicking the movements of a fly
caught in her web,
he lures her towards him.
He uses his massive
jaws to keep her at a distance
and avoid her lethal bite,
then paralyses her with his own
powerful venom,
before tucking in.
The intense competition for food
in Madagascar's crowded rainforest
has pushed its inhabitants to
evolve in the most extreme ways...
...and the lemurs are no exception.
This is an aye-aye,
filmed in a special enclosure.
Her favourite food is insect larvae,
which can only be found
deep inside the branches of trees.
But the aye-aye has perfected
a truly remarkable
way of getting to them.
It's a technique that's thought
to take four years to master.
Using her nine centimetre-long
middle finger,
she taps to hear where
the branch is hollow.
Then she gnaws
away at the protective bark...
...before deploying her
super-sized finger
to fish out any juicy grubs.
Madagascar's unique wildlife has had
millions of years to slowly evolve.
But in the last few thousand
years, the pace of life
has increased rapidly,
with deadly consequences...
...as revealed by a recent discovery
in Madagascar's most remote desert.
This pool is a portal to
a previously unexplored world.
In 2015, divers first ventured into
this network of flooded passages.
50 metres below the surface,
they entered a truly magical
underworld...
...discovering more than 11 km
of connected tunnels...
...and some of the largest
underwater chambers in the world.
But what they found
inside these caves
was even more remarkable...
...a vast graveyard...
...the preserved
remains of mysterious creatures...
...four metre-long
horned crocodiles...
...puma-like predators,
and ancient pygmy hippos.
But perhaps most impressive of
all...
...the skulls of giant lemurs that
grew to the size of a gorilla.
All long gone.
Their extinction coincided
with the most disruptive
change in Madagascar's
long history...
...the arrival of people.
And today, our impact on the island
is greater than ever before.
Madagascar's forests
are disappearing faster than
any other tropical country, cleared
largely for subsistence farming.
As little as 20% of the
island's original forest remains.
And the impact on Madagascar's
unique wildlife
has been devastating.
95% of lemurs are now
threatened with extinction...
...making them the most vulnerable
group of mammals in the world.
One of the most endangered is
found in the east of the island...
...the greater bamboo lemur.
Like all lemurs,
they're highly-specialised.
Bamboo makes up nearly 95%
of their diet,
despite being packed
with deadly cyanide.
Every day, a single lemur
can eat enough poison
to kill five humans.
They have evolved to
withstand its toxic effects,
keeping these thickets
all to themselves.
But now, their unique adaptation
has left them trapped here...
...unable to live anywhere else.
As their bamboo
forests are cleared for agriculture,
these lemurs are left
with nowhere to live,
and little to eat.
The greater bamboo lemur was once
thought to have gone extinct.
But thanks to a recent
concerted effort to protect them,
there is now a glimmer of hope.
In the last year, this group
had a record number of babies,
adding 72 to their total
population of 400.
The island of Madagascar has
reached a critical point.
And only with intensive conservation
efforts will its remarkable,
and unique wildlife
survive into the future.
Filming the critically endangered
greater bamboo lemur took
the crew to one of the most remote
regions of eastern Madagascar,
only accessible by a challenging
two-day drive.
The road is deteriorating.
The wooden bridges
are getting narrower.
The roads are worse
than everyone expected.
We appear to have already got
one of our vehicles stuck.
Finally, they reach Vohitrarivo,
a village close to one of the last
known refuges of this rare lemur.
Over the next two weeks, the crew
will be led by primatologist
Delphine Roullet, who came here
ten years ago on an urgent
mission to save the bamboo lemurs.
With the help of her organisation,
around 400 lemurs now live
in these pockets of bamboo forest,
but they're spread over a vast area.
Hopefully, we're nearly there
and can stop climbing up the hills.
To help narrow their search,
they head into the bush to meet
local lemur researcher Noret.
Ahead of the shoot,
he sets up camera traps to hopefully
establish the lemurs' whereabouts.
Let's see.
Oh, what's that?
There is one!
It's a good sign.
A troupe of bamboo lemurs were
in the area just a few days ago.
Oh, look, just here.
Yeah, completely dark.
But the lemurs can travel through
these thickets with ease, so it will
take all of Noret and Delphine's
skills to track them down.
I think Noret can see them.
I can't see them.
You can see a dark spot,
just straight.
They may have spotted them
in the distance,
but the lemurs are leading the crew
into even thicker vegetation.
I'm getting entangled in sticky
grass, and it's dense here.
No way this is going to work.
After nearly a week of tracking,
cameraman Justin is finally
getting closer.
But getting a clear shot of them
remains a significant challenge.
Yeah, right now there's two
just below us, but we can't film it.
There's too much vegetation.
Their wild lemur chase eventually
takes them to the
edge of the bamboo forest
and into the farmland beyond.
Noret and the crew check in with
the locals to get the latest
information on any
lemur sightings...
SPEAKS LOCAL LANGUAGE
...only to stumble upon the lemurs
right in front of them.
So, we've just turned
up to find them crossing this
section of rice paddy, between one
part of bamboo forest and another.
With much of their bamboo forest
cleared for agriculture,
the lemurs are forced to
venture into the open.
Sort of surprising to find them
here, because they really don't
like dogs, and the villagers keep
dogs, but so far they seem relaxed.
Although bamboo
is their preferred diet,
the lemurs will sometimes resort
to raiding rice crops.
In the past, this has led to
conflict with the locals,
but Delphine's project
has changed all that.
Villagers like Noret are
trained as lemur guardians.
They help study the troupes
and marshal them
off farming land before
any damage is caused.
Justin is still trying
to get his shot...
...when conditions take
a turn for the worse.
THUNDERCLAP
The rain makes filming quite
difficult, and it makes it
really hard to keep everything
and everybody dry, and not muddy.
So, at the moment the lemurs
are keeping their heads down,
so we're doing the same.
The lemurs may be close by,
but the rain continues
for four whole days.
We're just having to sit out
and hope they start moving
somewhere we can see them.
That frustration of having what you
want, but not being able to see it.
But all this rain brings about a
surprising change to their fortunes.
The rain triggers a flush of
growth in the bamboo shoots,
the lemurs' favourite food
and draws them out into the open.
So, it's been raining
nonstop for five days now
and I feel pretty
wet from top to bottom.
We can see six of them
stuffing their faces with bamboo,
which is a lovely sight to see.
I'm really happy to be
here, despite the rain.
It's amazing.
And there is an added bonus.
The mother bamboo lemurs have
timed their births to coincide with
the arrival of fresh bamboo
and the crew can film one of the
first newborns of the season.
Oh, it's so good to see the babies!
Cute!
Took a long time to get to this
point of actually having them
in front of us, so we can film them.
It's just great to have
moments like this.
These rare and intimate
portraits of baby lemurs is
the start of a record breeding year.
Over the following two months,
72 babies are born.
It's a huge boost to this
endangered population.
But their future
rests in the hands of the next
generation of lemur guardians.
A vital part of Noret
and Delphine's work is
sharing their knowledge with those
living side by side with the lemurs.
Thanks to Delphine, Noret,
and their dedicated team, one
of Madagascar's rarest lemurs
is now back
from the brink of extinction.
Next time, Borneo...
...home to a staggering
variety of habitats.
From its bustling coral reefs
and ancient rainforests,
to its mountainous heart...
...Borneo holds possibly the greatest
diversity of life...
...of any island.