Wildest Islands (2012–…): Season 2, Episode 2 - Amazon River Islands: The Floating Forest - full transcript

Some small or larger islands in rivers of the Amazon system are flooded annually for months. While birds can just keep flying, for most of wildlife everything changes, as the lush forest habitat drowns to become a wetland or back. Several species adapted thoroughly, sometimes even into a specialized subspecies.

(dramatic music)

- [Voiceover] Deep in the
heart of the Amazon rainforest

lies the largest collection
of river islands in the world.

Thousands of kilometers
from the nearest ocean,

these are some of the most
unusual habitats on Earth.

Stranded on the mighty Rio Negro,

(crash of thunder)

the islands are engulfed
by seasonal floods,

changing their landscape completely.

Everything living here is forced to adapt

or die.



This is life on the floating
forests of the Amazon.

(dramatic music)

(dramatic music)

The Amazon Rain Forest

covers 4,000,000 square
kilometers of our planet.

Sprawling across almost half

of the South American continent,

it is fed by the might Amazon River.

And at its heart are a group of islands

knows as the Anavilhanas

and Mariua Archipelagos.

More than a thousand islands stretch along

the Rio Negro branch of the Amazon River

and together make up
the largest collection



of river islands in the world.

Thousands of kilometers
from the nearest ocean,

these river islands are unique.

Surrounded not by coral reefs

and crystal clear waters,

but by flooded forests

and hidden dangers.

This is home to some of
the most unusual creatures

in the world.

(tiger growls)

(otter snarls)

Flooded for six months of the year,

the islands are a mass of submerged trees

and wandering vines.

This is a world like no other.

The forest floor becomes the river bed.

Fish feed from the treetops.

And canopy dwellers are stalked

by creatures that lurk beneath.

It's May and the flood
waters are starting to rise.

The lives of the animals
that call the islands home

take a dramatic turn.

(rustling of leaves)

Only two primates live here,

red howler monkeys

and the more common squirrel monkeys,

who have the run of the canopy.

(gentle music)

Because they spend much of the year

cut off from the mainland,

they've learned to adapt
to life above the water.

It's early morning and a large group

is heading out on a foraging expedition.

(adventurous music)

The monkeys make the most
of the daylight hours

as they move through the canopy.

They're on the lookout
for fruits, flowers,

and insects that make up their diet.

Long tails provide them
with excellent balance.

And aided by nimble hands and feet,

they're able to investigate
any opportunity.

But the canopy offers slim pickings.

Surrounded by water, the archipelagos

do not support the abundance of food

that is available to monkeys
elsewhere in the Amazon.

Some of the young males aren't impressed

with what's on offer.

So they decide to venture down,

deeper inside the flooded forest.

(gentle music)

The rewards are worth it.

Young monkeys have
incredibly good eyesight

and they're able to spot food

amongst the dense vegetation with ease.

They found a favorite.

The Clitoria flower's sweet
nectar is irresistible.

After a frantic morning foraging,

one of the youngsters is
desperate for a drink.

But it's a risky business.

Black caiman lurk below.

An alarm call alerts him to the danger,

but he's not out of trouble yet.

(dramatic music)

The slightest slip could be
fatal for the plucky primate.

Finally, he makes it back to the canopy,

where he's safe for now.

Giant reptiles are not the only predators

patrolling these waterways.

(tribal music)

None has a more fearsome reputation

than the piranha.

Blood in the water will whip them

into a feeding frenzy.

(swirling water)

These red-bellied piranhas

could strip a monkey to the bone

in a matter of seconds.

(swirling water)

Jaws filled with razor-sharp teeth

are designed to slice off
bite-sized pieces of flesh.

(water swirling and splashing)

As the waters continue to rise,

many animals become cut off.

A three-toed sloth is forced to brave

the treacherous waters
in search of a new home.

Despite the dangers, it has no choice.

Built for life in the treetops,

sloths are surprisingly good swimmers.

They paddle efficiently
with their long arms

and are able to move much faster

than they do on land.

But not quickly enough to go unnoticed.

(dramatic music)

Green anaconda are always on the lookout

for an easy meal.

This is an opportunity
too good to be missed

for one of the forest's
deadliest predators.

Chemoreceptors on the snake's tongue

help it track its prey's
movements through the water.

Finally, the sloth makes
it to a suitable tree,

but it's a long way to the top

and time is against it.

(music building in tension)

(splashing)

Once caught, the sloth
stands no chance of escape.

After such a big meal,

the giant reptile will last for weeks

or even months until it has to hunt again.

Life on the river islands is ever-changing

as water levels continue to rise.

The flood waters originate
hundreds of kilometers away,

high up in the Andean peaks.

(rushing water)

In December, as
temperatures begin to rise,

melt water from the
mountains starts to pour down

the Amazon's many tributaries.

(rushing water)

They flow east and gather forces.

(crash of thunder)

(rain pouring down)

These are joined by rainwater

as the wet season begins in earnest.

(dramatic music)

On the Rio Negro, rainfall is measured

not in centimeters but in meters.

The river bursts its banks and overflows,

flooding the river islands.

Amazingly, the rainforest
creates almost half

of the yearly rainfall itself.

(rushing water)

While the other half blows
in from the Atlantic Ocean.

(rain pouring down)

The islands of the Anavilhanas

and Mariua Archipelagos are transformed.

Water penetrates for a
distance of up to 20 kilometers

on either side of the main channels.

Whole islands disappear underwater,

and in places, only the treetops remain.

By June, the floodwaters have risen

by up to 10 meters

but there's still more to come.

Curtains of green hide the islands'

mysterious inner world.

Trees and plants have developed

a number of techniques for surviving

their months underwater.

Some choose to hibernate.

Some lose all their leaves.

And some even continue to photosynthesize

while submerged.

(lively music)

Throughout the river islands,

animals are adapting to the new challenges

the waters bring.

(bird calling)

Over two hundred species of birds

live on the islands of the
Anavilhanas Archipelago.

While some are looking for food,

others are looking for love.

Living out of reach of the flood waters,

birds are able to put all their energy

into courtship.

(bird singing)

A male streak-throated hummingbird

uses its enchanting
song and simple display

to attract potential mates.

(bird singing)

Although the flash of tail
feathers is impressive,

it's usually the best song
that wins the female's heart.

Deeper in the forest, another bird

goes to even greater
extremes to find a mate.

The wire-tailed manakin.

There are over 50 species
of manakin in the world

and the majority of these are found

in the forests of South America.

Stiff tail feathers give
the birds their name.

A male surveys the forest

from his private display perch.

He's ready to strut his stuff

at the first sign of a female.

It doesn't take long for one to arrive.

But unlike most manakins,
who display on their own,

wire-tailed manakins dance in pairs

as they attempt to win
the female's affections.

The pair take to the stage.

(upbeat music)

It's a dance off

and both are desperate to impress.

The female sizes up her
suitors from a distance.

Keeping a close eye on proceedings.

(music intensifying)

The dance comes to an end

with a show of dominance

and the female makes her choice.

All the loser can do is look on

as she leads the victor away.

(fluttering of wings)

Manakins are not the
only island inhabitants

preoccupied with passing on their genes.

Throughout the islands,

the larger and more established trees

have been waiting all year

for the flood waters to arrive.

Now, finally, they get what
they've been waiting for.

The trees use the waters
to distribute their seeds

far and wide.

(splashing)

(splashing)

The pods of a munguba tree

have spent the dry season maturing.

Now they burst open in spectacular style,

revealing seeds hidden

amongst the giant balls of fluff.

The seeds are scattered in the wind.

Each is attached to a parachute
to carry it on its way.

The seeds will be transported
throughout the islands,

hopefully, germinating where they land

and helping to maintain the forest.

But the munguba trees need to be quick.

Fresh food doesn't go unnoticed for long

on these islands.

(cheerful music)

Tui parakeets make the most

of the freshly opened seed pods.

The munguba tree is a favorite.

They use their beaks to pry the seeds

from their fluffy cocoons.

It doesn't take long for the hungry birds

to strip a pod.

At this time of the
year, there's more food

than they could wish for.

And they quickly move on to the next tree.

Parakeets are not the only animals

to take advantage of the fruit in trees.

Some seeds make a break for freedom

and float down into the forest

where more hungry mouths lie in wait.

(splashing)

(splashing)

While trees adapt to life in the water,

fish adapt to life among the trees.

(dreamy music)

South American trout, or brycon,

leap from the water to be
first to the falling seeds.

(splashing)

They can jump up to four
times their body length

in their quest for food.

Each mouthful is a
priceless source of protein

for the hungry fish.

(splashing)

Even though the seeds of the munguba tree

don't last long, some trees have learned

to use the fish to their advantage.

(dreamy music)

Amazonian flooded forests

are the only place in the world where fish

act as the major seed disbursers.

Trees can rely on more
than 200 species of fish

to distribute their seeds.

Many eat the fleshy fruit

before spitting out the unpalatable seed.

And by doing so, they help the trees

to deposit their seeds
throughout the archipelagos.

The flooded islands are inundated

with aquatic visitors of all
different shapes and sizes.

(suspenseful music)

But despite the wealth of food,

the islands are not
always the easiest place

for fish to live.

The quantity of decaying
leaves in the water

means that oxygen levels are low.

Bacteria and other microorganisms

use up supplies as they
break down the leaves.

As more and more of the
river's oxygen is used up,

very little is left for
the animals that live here.

The electric eel is a deadly predator.

But without a regular supply of oxygen,

it will not be able to hunt.

Like many fish in the black waters,

it's forced to the surface to gulp air.

Its mouth acts like a lung,

absorbing oxygen from the world above.

Another air-breather is the gigantic,

pike-like, pirarucu.

One of the largest known
freshwater fish in the world,

fully grown adults can
weigh up to 200 kilograms.

The three-meter-long
monsters rise to the surface

every 10 to 15 minutes to breathe.

This armor-plated giant

has survived for nearly 100 million years.

The Anavilhanas and Mariua Archipelagos

still provide a safe haven for them

and many other creatures.

(bird chirping)

These ancient islands were formed

during a time of change in the Amazon

over 1500 years ago.

Then, the black waters of the Rio Negro

did not flow so freely into
the mighty Amazon River.

Conditions were much calmer.

Sediment arriving from the
Rio Branco to the north

started to settle.

Joined by waters from the
Rio Negro's upper reaches,

pockets of forest started to form.

They developed into the
islands we see today.

(dramatic music)

Over time, the Rio Negro
once again picked up pace

and started to flow back into the Amazon.

The islands were left
and survive to this day.

But they wouldn't exist at all

if weren't for the white
waters of the Rio Branco.

Where, even to this day,

life doesn't just survive,

it flourishes.

(wild call)

One of the Rio Branco's
most charismatic creatures

is the giant river otter.

The otters spend most
of their time hunting.

Moving as a pack,

they're able to corral fish

before picking them off one by one.

(splashing)

(dramatic music)

Fresh fish make a fine breakfast.

Otters need to fuel
their energetic lifestyle

and can crunch through
up to four kilograms

of fish a day.

Catching the fish with their mouths,

they then hold them with their forepaws

as they devour their prey, scales and all.

But these deadly predators
have a softer side

and when breakfast is over,

it's time to play.

(splashing)

Giant river otters live
in large family groups

and it will be some time
before last year's cubs

head off to form families of their own.

(splashing)

Family life revolves around the den.

The mother remains hidden

while she raises the next generation.

With several dens dotted
around their territory,

the family move regularly
in the search for fish

and to avoid unwanted
attention from predators.

Just a few months old,

the cubs must be carried

as they're still too young to swim.

The family head off up river.

(laid back music)

Arriving at their next den,

the first priority is
to get the cubs inside

where it's safe.

The father keeps watch

while his family settles
into their new home.

(calling softly)

The males scent mark the entrance

to warn others that they
are now in residence.

It's a pungent concoction that will keep

even the nosiest neighbors away.

(relaxing music)

All along the Rio Branco,

life flourishes on the
sediment-rich waters.

The river banks are dotted with wildlife.

(bird calling)

Including the largest
rodents in the world.

Closely related to the guinea pig,

capybaras are equally at
home in or out of the water.

But the wealth of animals
attracts unwanted attention.

(capybara calls out)

A jaguar stalks the river bank.

Capybaras make a tasty meal.

The Amazon's apex predator

is rarely found far from the river,

and the abundance of
food on the Rio Branco

makes it an ideal hunting ground.

(capybara calls out) (splashing)

When escaping dangers,
the giant rodents can dive

and remain underwater
for up to five minutes.

(dramatic music)

The jaguar stalks off silently

to continue its search for food.

(sounds of the rainforest)

Back on the river islands,

the mid-morning peace is shattered.

(monkey howling)

Red howler monkeys can be heard

throughout the islands.

These secretive primates don't only use

their roaring calls to deter predators,

they also use them to
mark their territory.

(monkey howling)

Unlike their island neighbors,
the squirrel monkeys,

they tend to travel in smaller groups

and stick to the top of the canopy.

Excellent acrobats, the monkeys

rarely come down to the ground,

and during the floods,
they're even more reluctant,

all too aware of the
dangers that lurk beneath.

(gentle music)

It's now late July and water
levels are at their peak.

The forest floor has sunk
under 15 meters of water.

The flood waters bring about a change

in everyone's lives.

A colony of fire ants has been forced out

of their underground home

by the rising water levels,

providing an easy meal,
despite their painful sting.

(dramatic music)

This tree will provide a safe haven

until the waters fall

and they can return to the forest floor.

The resilient ants quickly move

into a vacant crack in the bark.

Some animals don't just survive,

they thrive in the new conditions.

(wild call)

(relaxing music)

Leaf cutter ants swarm through the trees.

Able to carry pieces of leaf

weighing 20 times their body weight,

they're born to work.

These are no ordinary ants.

It's believed their a separate species

to the ones who nest underground,

and they've developed a unique behavior.

They've swapped the forest
floor for the treetops.

By building their nests in the canopy,

they avoid the annual floods,

so, despite the rising waters,

they continue undisturbed.

Colonies can contain up
to 8,000,000 individuals,

making it one of the
most dominant creatures

in South America.

And one of the river islands'
most resilient residents.

Worker ants are sent
out to collect supplies.

Foraging far and wide,

they're able to find their way home

by laying out a thermal trail.

The pheromone is so powerful,
one gram of the scent

would be enough to lay an ant trail

all the way around the world.

Only the freshest and
juiciest leaves are selected.

Powerful jaws slice through
the cellulose with ease.

(dreamy music)

Once loaded up, the ants
then begin their journey

back to the nest.

Leaf cutter ants cultivate
a special fungus garden

deep within the nest.

(thoughtful music)

And are almost entirely
dependent on the fungus for food.

Maintaining the garden is crucial

to the survival of the colony.

Only the queen is able
to produce offspring.

She's capable of laying
thousands of eggs per day,

most of which are destined
to become workers.

The ants are true forest specialists,

and, out of the reach of the flood waters,

they continue to dominate.

Other insects have not adapted

to their new aquatic home quite so well.

Some are forced to venture
across the water's surface

in search of dry land.

It's a crossing fraught with danger.

Arowana lurk beneath.

The fish patrol close to the surface,

scanning for prey.

No insect is safe.

As the flood waters rise,

more and more get washed into reach.

It's a time for the arowana to fatten up

before the long dry season returns.

(splashing)

Some of the waterways'
more unusual creatures

are also taking advantage
of the new food available.

Needlefish lie just beneath surface.

Their slim profile helps
them to avoid detection.

They hunt by sight and are ready

to take advantage of any stragglers.

(water shwooshing)

Unlucky spiders are picked off with ease.

Carnivorous fish are not
the only underwater animals

enjoying a glut of food.

One of South America's largest animals

lurks in these waters.

The Amazonian manatee is an iconic symbol

of the Anavilhanas and
Mariua Archipelagos.

(reverent music)

Hiding out in the quiet backwaters,

they gorge on the food that arrives

with the flood waters.

For the manatee, this is a time of plenty.

And also a time to rear their young.

These shy mammals give
birth to a single calf

once every two years.

The mother will spend time
teaching the youngster

the best routes through
the maze of river channels.

The calf will need all its
mothers knowledge and support

with the dry season fast approaching.

It's now August

and the rainy season is coming to an end.

Water levels are finally starting to fall.

The animals and plants that
have survived the floods

can look forward to drier times ahead.

Eking out a living on
the ever-changing islands

can be a challenge,

but there are always ways
and means of doing so.

As the flood waters start to fall,

spectacular fish begin to appear

in the shallows of the forest.

Cardinal tetras are
found deep in the heart

of palm forests along the black waters

of the Rio Negro.

(speaking foreign language)

This family makes the
eight-hour round trip

from their village each day

in order to gather the tiny fish.

(thoughtful music)

(swirling water)

Their catch is destined
for exotic fish tanks

around the world

and provides the family with
a vital source of income.

Come midday, it's time to
head back to the village.

(hum of motor)

On their return, the
fish are quickly sorted.

The highly prized cardinal tetras

are separated and piled into boxes.

A thousand fish sells
for around five dollars.

A decent income, but
the family supplements

by hunting and fishing.

Once the morning's work is done,

the pace of village life slows.

(relaxing music)

By the end of September,
the heavy rains cease

and the water engulfing the river islands

has fallen by almost a third.

As the levels drop, beaches reappear.

For many, life starts to become easier.

Butterflies feed on freshly exposed land.

Migrant birds return to nest.

(bird calls out)

Newly exposed plants burst back into life

with a flush of green.

Squirrel monkeys are less fearful

of the world below as the
retreating flood waters

lead the dangers away.

Which is also good news for the sloths.

But for the islands' wet season visitors,

it's time to move out.

The manatee mother and calf

have feasted for the past four months.

They must now prepare to
return to the main channels

and begin their dry season fast.

And fish are also forced to leave

the islands' flooded forest

and return to the deeper river channels.

(triumphant music)

The Anivilhanas and Mariua Archipelagos

spread along a 1,000 kilometer
stretch of the Rio Negro.

They provide a home for
some of the hardiest animals

in the world.

As flood waters engulf
the islands each year,

those that live here are forced to endure

incredible extremes.

But animals have developed ways of coping

and have learned to master
their ever-changing environment.

It's either sink or swim

here in the floating
forests of the Amazon.

(dramatic music)