All language subtitles for The Falls of Iguacu BBC Natural World 720p HDTV

Deep in the heart of South America

lies one of the most spectacular
secrets of the natural world

Iguacu

one of the planet's largest waterfalls

It's a fearsome display
of the raw power of water

but it also has a gentler side

A vast and continuous cloud
of fine spray

rises up over the surrounding trees

This refreshing moisture nurtures
a very special section of rainforest

a biological hotspot for some of
South America's most amazing animals

But Iguacu National Park
is a refuge fighting for survival

Dedicated teams work tirelessly
to guard it from poachers
and illegal loggers

Drastic action is needed

but this is a hard place to police

In the wet season

Iguacu can have up to
300 individual falls

draining from the hundreds of
kilometers of surrounding forest

Can this magical place be saved?

Around 120 million years ago

the rupture of
the supercontinent of Pangea

led to the creation of
Africa and South America

Lava bursting through

hardened into giant blocks
of fine-grained basalt

This is the rock from which
the Iguacu waterfalls have
been sculpted grain by grain

Basalt is such a hard rock
that it erodes very slowly

leaving behind a line of cliffs
up to 82 metres tall

At one point 7 miles long

Iguacu's horseshoe-shaped falls
are nearly 3 times the size of Niagara

In the wet season

enough water flows
over the edges every day

to supply the city of London
for more than a year

The torrent could drag you
to your death

but Great Dusky Swifts
fly right through it

Behind the wall of water

they are safe from predators

Most other animals have to make do
with the spray-drenched forest

which surrounds the falls

Tucked away, some 15 metres
up in the canopy

lives one of Iguacu's most
successful mammals

the ring-tailed coati

a relative of the raccoon

Every year they produce
a litter of up to six cubs

It's risky place to raise young

but it's a lot safer
than on the ground

Jaguars

the mightiest cats of the Western
Hemisphere, still roam here

But they're in steep decline

Good news for the coatis perhaps

but bad news for
Iguacu National Park

These forests used to
stretch back from most of
Brazil's Atlantic coast-line

Now only 7% of this unique
Atlantic rainforest is left

Iguacu

straddling the border
between Brazil and Argentina

is one of the last refuges
for the outstandingly rich and
endemic wildlife of the area

known locally as the 'Mata Atlantica'

In the eighties

Iguacu was given
World Heritage status

but it was steeped in folklore
long before this

A native legend tells of Naipi

daughter of a tribal chief

a girl so beautiful that the Iguacu
River would stop to admire her

Tarob�� a brave young warrior

fell in love with Naipi,
and won her heart

With each passing day

their feelings grew stronger

But the chief had already
chosen Naipi to be sacrificed

to honour their ruling
serpent god, M'boi

The night before the sacrifice

the couple made their escape

Little did they know that
the god M'boi was watching in fury

The waters raged with the Gods wrath

and a gigantic gorge
opened before them

Thus the demise of
Naipi and Tarob��

was the creation of
the Falls of Iguacu

In what is now called
the Devil's Gorge

it is said their spirits
remain forever

Each Spring

new life emerges from
this bewitching place

Flocks of up to three thousand
swifts come here to breed

The birds clamber over each other

as they attempt to show
themselves off to best advantage

On these precipitous cliffs

the ability to Hang On might be
the most attractive trait of all

Despite their numbers at the falls
they have been little studied

and their courtship behaviours
are not fully understood

The acrobatics continue for several
days on both sides of the cascade

Until eventually the birds pair off

But nothing about life
on the falls is easy

the female allows the male
to court her

but often rejects him over and over

He offers her some useful nesting
material for her hard basalt hollow

but even that doesn't do the job

The flirting eventually pays off

and it's time for the flying
circus to begin family life

While the swifts are just
starting to build their nests

the baby coatis are growing too
boisterous to stay inside theirs

They're three and a half weeks old

and getting a taste for adventure

The mother has two more weeks
teaching them the ropes on her own

Like their mother

the babies need to become
excellent climbers

it's vital for finding food

but also for escaping from predators

For now, though

it's one step at a time

Despite the occasional mishap

the youngsters quickly cotton on

Long tails help to balance

while strong, sharp claws
grasp the bark

as they literally hang on
for their lives

And, if they ever lose their nerve

help and encouragement is at hand

After about 6 weeks
isolated with their young

mother coatis reassemble
into large social groups

that can number more than
60 individuals

Even after short periods apart

coatis engage in excitable greetings
and groom each other

At last, relief from
looking after the kids

mothers take turns running a cr��che

Some go off looking for food

while others watch over the unruly cubs

Iguacu appears idyllic

but scientists in the park fear that
many treasures have already been lost

There is little knowledge of life
in the forest beyond the falls

Both Brazilian and Argentine scientists
are working hard to put that right

Ricardo Melzew is part of
a special Jaguar project

funded by several government departments

They've discovered that
in the last 15 years

Iguacu's jaguar population
may have suffered
an 8 fold decrease in numbers

Researchers use cameras to
spy on these elusive predators

An infrared sensor is tripped
by passing animals

producing snapshots of
jaguars' secret lives

These can tell Ricardo
and the team a good deal:

We use a camera trunk
to track the cats

especially the spotted ones
like the jaguar

Each jaguar has unique spot patterns

like fingerprint

so based on those we can tell exactly
how many individuals there are

Back at the lab

the researchers face the challenge
of interpreting all their data

Do Iguacu's most powerful feline
predators stand any chance of survival?

Iiaria Agostini thinks the evidence

from photos, feces and footprint
casts all points one way

Jaguars are disappearing

first and foremost,
because of hunting

There are many records of jaguars
killed by poachers who shoot them

in order to sell their skin

or just for the thrill
of killing a jaguar

But the most recent snaps
offer some encouragement

They've identified
a male-female pair

Extremely good news

as the park population is estimated
at a mere twelve individuals

Maybe this pair will breed

But it's not just jaguars that
scientists want to protect

This is a special bird

in its element at Iguacu

The snail kite depends on water
to supply its main food source

juicy amphibious apple snails

The kite may eat as many
as 70 snails a day

so it regularly patrols
the fast-flowing water

Some rapids are too
powerful for fishing

though the kite seems able to
cope with the strong currents
at the edge of the falls

Few birds of prey
are this specialized

The ultra-rounded beak is
perfectly shaped for scooping out

and lacerating the muscle tissue
that binds snail to shell

With the rainy season is underway

activity around the falls
is hotting up

Red-rumped caciques are well into
a huge nest-building programme

The males do the hard graft

and the females keep tabs on them

An elaborate series of knots

secures the long tear drop
shaped nests to the tree

With dozens of couples
living in a single tree

the occasional dispute is unavoidable

Desperate to finish in time

a cacique may steal a neighbor's
supplies to get ahead

But community life has its advantages

Large colonies mean better protection

when the nests host precious offspring

After the clamour from
the cacique colony subsides

yet another of Iguacu's residents
joins the wait for a new generation

A mother caiman listens carefully

Nearby, her nesting mound
contains up to sixty eggs

This is the sound
she's been waiting for

The babies synchronize their
emergence by calling to each other

while still inside the egg

The mother caiman has protected
this mound for 90 days

Now, by hatching all at once

her babies have further reduced
each individual's chances

of being picked off by monkeys,
lizards or birds

The hatchlings head
directly towards water

where they will remain under their
mother's guard for several months

But tonight, they've been spotted

Fortunately they're being hunted
by park biologists

carrying out their annual caiman census

Just as jaguars can tell scientists
about the overall health of the forests

broad-snouted caiman numbers
are a good indicator of
water quality in the park

Caiman are very vulnerable
to pollution

The main threat to them,
however, comes from people

Many caiman are hunted for meat

but the broad-snouted caiman is
especially targeted for its unique skin

used to make fine leather goods

When Justo Herrera and the
Argentine National Park team
began the study ten years ago

the caiman population was alarmingly low

"The drop in the Caiman population
was due to heavy poaching in the area

Now, there are more
park rangers on patrol

This seems to have deterred hunters

letting the population
begin to recover"

These are small but hopeful signs
for Iguacu's future

The swifts are also doing well

If the sun is shining the swifts
will be on the wing

It's summer and temperatures have
risen by around 10 degrees Celsius

The mist cloud creates a super-humid
micro-climate around the falls

but the swifts have the ultimate
antidote for the oppressive heat

The high-pressure showers
are not only cooling

they help rid the birds of parasites

Feathers need to be in top
condition for their aerial stunts

and long hours on the wing

The swifts compete for the nooks
and crannies under the falls

which will make the best nest sites

Nest-building is soon under way

Materials include plants, feathers
and moss from all around the falls

But it's their own saliva
that will help glue the nest
to the slippery rock

In the carefully prepared crevice

the swift lays just a single egg,
guarded with utmost care

Virtually no nest predator
can get up here

so the swifts have no need to
reproduce in great quantity

The eggs take an unusually
long time to hatch

possibly because of the chilly
conditions in the dank hollows

Nearby, the 3-month-old coati cubs
have become intrepid explorers

They're nimble climbers now,
and growing fast

which means they're in
constant search of food

But their playful antics can
also put them into grave danger

it's not wise to annoy some
of the jungle neighbours

The South American rattlesnake
is one of the most poisonous
of the rattlers

its venom can easily kill a human

let alone a young coati

But when hot on a scent

the cubs often take little notice
of other creatures around them

The bone-chilling rattle should
be enough to send anyone running

But young coatis are
both naive and curious

The rattle is the warning

Provoking it is a deadly game
to play for the youngsters

Its neuro-toxic venom invades and
disrupts the victim's nervous system

The coati cubs survive another day

but the fate of Iguacu as a whole
remains less certain

Iguacu is a large island
of rainforest

surrounded by a huge sea of farmland

The long term impact of
the encroaching areas
remains to be seen

In a pioneering expedition
to find out more

scientists are penetrating deep
into the little-known heart of Iguacu

and the pristine Floriano River

This is as far as the chopper
will take them

The team is led by National
Park biologist Alcides Rinaldi

and visiting specialist
Carolina Ribas

They hope to find traces
of the giant river otter

a species native to the area
whose current status is unknown

They're accompanied
by Adaildo Policeno

who once made his living as poacher

For team-leader, Rinaldi

this is unknown territory

"This expedition is a rare
chance to explore an area

where very few people
have ever set foot

It's totally remote

closed off to visitors

So it can give us a look
at how this whole region
must have been long ago"

Some of the local inhabitants
are agitated by the group's arrival

These are so-called 'killer bees'

a dangerous hybrid descended
from escaped African bees

originally brought to Brazil
for honey production

Their aggressive nature
and the number of stings
sustained by the team

threatens to end the expedition
before it's even started

The river offers an escape
from the harmful bees

and the oppressive summer heat

The group heads off
as quickly as possible

The biologists are looking
out for any signs of
the 1.8m long giant otter

But expert, Caroline Ribas

believes this part of
the river isn't quite right

"I think there's too much current
here to be giant otter habitat

The water is very clear and
there aren't many large fish

So far we've seen a lot of
common river otter marks

but no sign of any giant otter

I'm hopeful though!"

It's so remote here that it's
possible to see very rare animals

even the fugitive jaguar can
prowl here in relative safety

The name jaguar comes from
the indigenous word "yaguara"

meaning "the beast that
kills his prey in one leap"

So even large mammals must remain
vigilant in this dense forest

Excellent hearing and
a keen sense of smell

will help keep this tapir
out of trouble

The Brazilian or lowland
tapir has a unique crest
along the back of its neck

thought by some scientists to be
a protection from jaguar attacks

Its ancestry links it
to the primitive horse and the rhino

Despite appearances

tapirs are good runners and
have extremely tough skin

If frightened or attacked

they will rush into water to escape

A 200kg tapir would be
several days' worth of food

But only an experienced jaguar
would succeed in bringing one down

Most jaguars don't get that far

Along the rivers
in the Iguacu heartland

are some of
the greatest concentrations
of butterflies on earth

rivaling the spectacle
of the Amazon rainforest

Scientists reckon that there may be
over 800 different species in the park

but so far only 257 have been identified

They gather in huge numbers
on damp ground

because these are the best places to
absorb essential salts and minerals

Unfurling their straw-like tongues

they suck up huge amounts of water

Inside their bodies the necessary
minerals are filtered out

and the surplus river water is
steadily flushed out at the other end

These gatherings
are almost exclusively male

And it's competitive

The males pass their mineral strength
to the female when they mate

So filtering more water now
will increase the chances
of passing on his genes

Along the nearby Floriano River

the search for the giant otter continues

The team has paddled and hacked its
way through a 40km obstacle course

Finally they reach the place
where ex-hunter, Adaildo Plicenoa

remembers seeing a giant otter
six years ago

"Here, between the first
and second waterfalls

I saw a giant otter
sitting on this rock

He was looking up in that direction

The water was high and he was
sitting right here eating a fish"

"It caught my attention
because it had a white mark here

"Was it near its mouth,
or on the chest?"

"More on the chest

Historically giant otters were easier
to find in the rivers of Iguacu

Social and gregarious

they live and hunt in packs

earning them the nickname
of 'water wolves'

But in recent decades

sightings became fewer and fewer
until, in the late 1980's

the otters seemed
to disappear altogether

Along the banks

Carolina Ribas and the team find only
traces of the smaller, common otter

"Right here we've found
some common otter mucous

they use it to mark their territory

Look at this here

Here on the bank

you can see really clearly where
the otters have left claw marks"

There's an otter's holt

but it also belongs to a common otter

The whereabouts of its elusive
giant cousin remain a mystery

The Floriano River starts
and ends on protected land

making it one of the purest
waterways in Iguacu

If the giant otter is to be found
anywhere it should be here

They check each stretch
of the river for likely spots

"We've reached a part
of the Floriano river

that's deeper and calmer
any of the sections
we've encountered so far

It's around 4 and a half feet deep

That means there are
probably more fish here

which would make it a more likely
place to find giant otters

Unfortunately we haven't found
any traces of them yet"

"Not finding a single sign is
a disheartening end to the expedition

Giant otters are very
sensitive to pollution

Could contaminants from
the surrounding farmland have
already seeped into the park?

It's a reminder of how easily
the balance of nature

in this island of rainforest
can be upset

The arrival of the annual rains
can be quite disruptive too

Some animals benefit
from the extra food on offer

But a violent rainy season raises
river levels at an alarming rate

Recently, Iguacu experienced
intense rainfall

The flow over the falls
reached a staggering
17,000 cubic meters per second

one of the highest since records began

Normally, the falls provide unparalleled
protection for the great dusky swifts

Now the waters threaten
to destroy this year's brood

and take down the adults too

Life becomes both a matter
of endurance and luck

Here, the river has risen
an incredible 20 metres

nearly swallowing some of the falls

The swifts are resilient

and within days they are back
in action, re-building their lives

The coatis take the rainy season
in their stride

Their life is spent high and dry

The coati diet is very varied

and much of what they need
can be found in the trees

But they do get their feet
on the ground

to find protein-rich invertebrates

and their elongated up-turned snout
is ideal for rooting them out

For digging into the best bug hideaways

their climbing claws
come into their own

This year's cubs are discovering
that Iguacu's forests

offer a fantastic variety of fruit

No wonder coatis are doing well here

They can get around quickly

thanks to a reversible ankle joint
which gets them down trees head-first

and they are learning fast

both from each other and
their adult chaperones

For now the pack travels as a group

But before the youngsters
reach their third year

things will change

The females will stay
with their mothers

but the males will have to
peel off on their own

Young male coatis need to make
the most of the precious time

spent under their mother's wing

At sundown,
when the coatis are tucked up

different characters
emerge around the falls

On the forest floor

one of the true terrors of the night

Already the size of a human hand

the tarantula can take on prey
even larger than itself

Hairs on the tarantula's body

form an array of sensory
hunting equipment

They allow it to detect heat

chemicals and vibrations in the air

A perfect predator

Just one of the helpless,
blind mice would be a perfect meal

enough to satisfy the tarantula
for several days

Babies everywhere are under threat

The nests at the cacique colony
are now full of chicks

Adults are on full alert

even before the first rays
light up the forest

Red-rumped caciques have plumage
to match their noisy nature

As the chicks begin to stir

their parents begin
the daily grind to feed them

Some of the caciques have already
lost chicks to predators

but many nests still contain one,
two or even three hungry mouths

desperate for an insect breakfast

But they always keep
an eye out for danger

Their enemy, the Toco toucan,
doesn't need camouflage

It's big, and it's pushy

The combined efforts of the cacique
colony are no real match

A cacique chick is just a protein
supplement in the toucan's fruity diet

But in mere seconds

a cacique's season of labour is lost

The Park authorities can also
find their hard work undermined

Poachers are at work in Iguacu

and Brazilian and Argentine rangers
join forces to root them out

Apol?nio Rodrigues,
Vice-President of the Brazilian park

scans the riverbank for any
tell tale signs of infiltration

Argentine head ranger,
Jorge Cieslik, shares command

There's no telling
what they might find

poachers can be heavily armed

Rodrigues and Cieslik are sure
they're on the right track

"Clearly there is a camp nearby."

"There is a path cleared
that splits off

We know there's nothing
in one direction

but in the other direction
it's likely we'll find the camp

"When we first got here��"

"We heard firecrackers
when we got here

That's their accomplices
warning them

So now we know they are in there

But taking the suspects
by surprise will not be easy

The rangers advance cautiously

in this remote patch of forest
there's no back-up

The ambush is successful

but the rangers know
these are the little guys

Local people are poor

Hunting, although illegal

can bring in many times
the minimum wage

The rangers collect up evidence

which includes some dangerous,
primitive weapons

and the remains of a rare
white-lipped peccary

"This is a homemade canon,
old-fashioned style

Our friends here set them up
all around the park"

"This one's been well-used already

They set up a wire,
and when an animal trips it"

"��it pulls this trigger here"

"Hunting has always been
a problem in the park

It has increased
because it's so lucrative

People no longer hunt
just for themselves;

they sell kills to dealers

or sometimes they work on special
order for people in the area"

Now the park rangers themselves
have to use increasingly radical

and sometimes violent tactics

In this tranquil place

it seems to be the only way to give
Iguacu's wildlife a fighting chance

Around the falls the coatis numbers
have become more concentrated

maybe taking advantage of the decline
in big cats such as the jaguar

The ground has become a much safer
place for the young males to spar

This is practice, perhaps

for when they need to fight for
the right to mate with females

Soon the young males
will have to leave

already they are testing
their independence

They've already started to build
their own sleeping nests near the group

It's time to reaffirm group bonds

and settle in to replenish their
energy for the adventures ahead

The worst of the rainy season is over

and the falls at Iguacu
are back to normal

The swifts have recovered
from the raging flood

and the single chicks
are growing strongly

They're demanding little things

hungry for insects that
the parents catch in mid-air

For weeks the chick has observed
his parents' fearless flight path

But that won't make its maiden
plunge any less harrowing

Mum and dad form a safety net
while the chick tests its wings

Then comes the day of reckoning

The falls are
a formidable place to live;

a gated fortress to which
only the swifts have the key

The grand falls of Iguacu
are a world monument

That status has helped to protect

the remnant of Atlantic
rainforest that lies behind

It is sobering to think that
without this fantastic spectacle

an entire wild community
might already have disappeared

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