(VARIOUS ANIMAL CALLS)
DAVID ATTENBOROUGH: Forests at first sight
may seem quiet and tranquil.
(SOFT PATTERING)
But today we can explore them in new ways...
...and from a new perspective.
And, in fact,
they're full of unexpected connections,
relationships
and even secret messages.
Only now are we discovering
how strange and complex
forests actually are.
The rainforest of Borneo.
A pair of oriental pied hornbills
are renewing their partnership.
They mate for life.
And this year's nesting season is just starting.
(BIRDS CALL)
Before they face the challenges ahead,
they reaffirm their bond.
And they do so with an unusual ritual...
...at the entrance to a bat cave
that they know well.
This rather curious gift
isn't normally on their menu.
But it both demonstrates devotion
and reassures the female
that her mate will provide for her.
In the coming weeks, she will depend on him
in the most extraordinary way.
Nesting is a dangerous time for any bird.
The hole in this tree trunk
will provide vital protection.
Just what she wants.
Once settled inside...
...the female does something truly bizarre.
She pulls out her flight feathers.
She is not going to need them
because she will be staying in here for quite some time.
It's not only a little cramped,
it also lacks basic amenities.
Now her partner brings her a beakful of mud.
And she begins to seal herself in.
She has turned the tree hole
into a predator-proof fortress.
But it's also...
...a prison.
Her partner, however, is a regular visitor.
For the next two months,
he will deliver all her food
directly to her door.
But she can be fussy.
He's going to have his work cut out.
Delicious.
It may seem
that he has been doing all the work.
But she, too, has been fully occupied.
The food he has brought
has enabled her to produce two precious eggs.
She will keep them safe for another six weeks
until the young have grown and fledged.
And then, both she and they
will break out of their confinement.
But until then...
...this devoted couple
are going to be very busy indeed.
The warmth and the moisture of rainforests
enables their inhabitants to flourish
in both numbers and variety.
And here, in the Amazon, live many strange species.
(SOFT HOOTING)
This is a treehopper.
One of hundreds
of different types in this forest.
They not only have a bizarre appearance...
...but they also communicate...
(DEEP PURRING)
...in a remarkable way, too.
(CLICKING AND PURRING)
Vibrating their bodies, they send signals
through the forest plants they live on.
(CLICKING AND PURRING)
Most of these messages
we can only hear by using special microphones.
(HIGH-PITCHED TONES AND PURRING)
Each treehopper species has its own repertoire.
(GENTLE HOOTING AND DEEP RUMBLING)
(HIGH-PITCHED BUZZING)
And every sound...
(DEEP THUDDING)
...has its own particular meaning...
(HIGH-PITCHED WAILING)
...whether it is to attract a mate...
...share information about food...
(WHOOPING)
(RASPY CLICKING)
...or warn each other about the arrival of predators.
(RASPY CLICKING)
(PURRING)
This treehopper mother communicates with her young,
encouraging them to stay together
so that she can protect them.
For there are plenty here
waiting to eat young treehoppers.
Ants.
On the hunt.
Treehoppers know how to defend themselves.
But not all threats are so easily dealt with.
An assassin bug.
Armed with piercing mouthparts
and sticky front legs...
...capable of literally sucking the life
out of her entire brood.
(PURRING AND CLICKING)
She can try to block the assassin's path.
But she can't guard them all.
She needs help from friends in high places.
Bees.
They're very aggressive.
This is more than the assassin bug bargained for.
Mission accomplished.
Her brood are safe.
The bees don't protect the treehoppers for free.
A little tickle on a treehopper's back...
...and they exude a sugary liquid.
Honeydew.
A sweet reward for protecting them.
It's just one of the countless ways
in which forest species work together.
In the forests of India,
you can hear a unique and truly extraordinary sound.
(WHISTLING)
These are dholes.
Wild dogs that Whistle.
Like treehoppers, they, too, communicate in secret.
But for a different reason.
(DEEP RUMBLING)
Hunting in a dense teak forest is difficult...
...especially so if your prey is three times your own size.
The only way for dholes to succeed
is to work as a team.
This family has four growing pups.
A chital deer could feed the entire pack.
The pack must get close...
...without being detected.
(GRUNTS)
But with eyes and ears everywhere...
...the deer are soon aware of the dogs' presence.
(SQUEAKING AND RATTLING)
The pack can't afford to give up.
They may have better luck here.
The vegetation is dense and provides better cover.
But the dholes could easily lose track of one another.
So they use their unique Whistles.
(WHISTLING)
Only dholes can understand
these quiet, unobtrusive calls.
(WHISTLING)
Now they take up their hunting positions...
...even though they can't see each other.
(WHISTLING)
With the deer surrounded...
...the dholes wait for the signal to attack.
(WHISTLES)
(YELPS)
Some of the dholes split the herd...
...and drive a stag
towards others waiting in ambush.
(WHISTLING)
The dholes' ability to communicate so quietly
enables them to stay connected,
and so hunt successfully
in the tangle of their jungle.
The mountainous forests of Central China.
Until recently,
these were among the least known of forests.
They're full of swirling mists,
and few outsiders had any idea
of what they might contain.
(THUNDER RUMBLES)
Living in such dense vegetation,
it's difficult to make yourself seen.
Even when you want to be.
And that's a problem
for this male Temminck's tragopan.
He has lived most of his life alone.
And this is his first mating season.
(CHIRPS)
He needs to make himself conspicuous
in the gloom of the forest floor,
and he's found a clearing Where he might do so.
A female.
(SQUAWKS)
She, too, is looking for a mate.
This could be his moment.
(WHIMSICAL MUSIC)
Oh, dear.
(CHIRPS)
Stage fright.
(SQUAWKING)
And who is this?
A male golden pheasant.
He, too, has come to this clearing...
(SQUAWKS)
...to attract a female.
And he seems a little more confident.
So that is how it's done.
The tragopan might still have a chance.
Here is a new female.
But is she interested?
It's time to be bold.
(RHYTHMIC RATTLING)
He pumps up a pair of horns
and a multicoloured bib.
It's a sight to be wondered at.
And it has never before been filmed in the Wild.
Not today.
How deflating.
(CHIRPS)
The temperate rainforests of Western Canada.
Some of the trees here are 1,000 years old.
It's autumn,
and the beginning of a spectacle that, each year,
transforms this forest and all that lives in it.
After years at sea, thousands of Pacific salmon
are returning to these streams to breed.
(SOFT GRUNT)
And they attract the forest's rarest resident.
A spirit bear.
A white variant of the black bear.
Fewer than 150 exist,
and they're found only here.
This female
has fished for salmon here for 20 years.
Get your timing right...
...and there can be great rewards.
In her youth, she was, in fact, even more successful
than the black bears.
Perhaps her pale coat
makes it difficult for the fish to see her
against the bright sky,
and that could give her an advantage.
But now she is old
and this year she's finding it hard.
Her fishing skills, however, haven't totally deserted her.
This annual feast helps her to fatten,
ready for the Winter ahead.
But it also helps
the patch of forest Where she lives.
This female
has an unusual relationship with the forest.
Every fish carcass she leaves behind decays,
releasing nutrients that soak into the soil.
And there...
...they are collected by a network of fungi.
The threads attach themselves to the tree's roots.
And nutrients from the fish, collected by the fungi,
are then passed on to the trees.
As a consequence, the forest around the river
grows three times faster than elsewhere...
...and some trees here
become as tall as any in the world...
...and provide spirit bears with a healthy forest home.
We now know
that such relationships exist in forests all over the world.
At the heart of these many connections
stand giant trees, like this one.
A kapok.
It started life as a seed some 200 years ago.
Now it towers 60 metres above the forest floor...
...and transports 1,000 litres of nutrient-filled water
from its roots
up to its canopy every day.
So this giant gives life to others.
A whole community of animals and plants
depends on the wellbeing of this one tree.
(CHAINSAW BUZZES)
A single out made in just a few moments
has broken thousands
of long-established connections.
Across the world's forests,
this story is being repeated endlessly.
15 billion trees
are cut down every year.
Every one of these trees
is, in itself, an intricate ecosystem.
But here in Brazil, they're being replaced
by plantations of a single species of tree.
Originally from Australia...
...these eucalypts are unable to build relationships
with most of the native plants and animals.
And, worse,
these newcomers grow so rapidly
they extract nutrients from the soil
faster than they can be replaced.
And what was once a rich and complex world...
...becomes little more than a green desert.
And at just five years of age...
...their lives are ended.
They're felled and taken away.
Their wood is then pulped to make paper.
And all that remains of the rich rainforest
are a few tiny patches.
Patches so small
that few of the original inhabitants
are able to survive in them.
Uganda, East Africa.
This small group of chimpanzees
have a detailed knowledge
of the forest territory that they inherited
from previous generations.
They know the best places to shelter,
to raise their young...
...and to feed.
This fruiting tree
cannot by itself sustain the chimps for long.
The alpha male signals that it's time to move on.
(GRUNTING AND SCREECHING)
Where he goes, others will follow.
He leads them not to another fruiting tree...
...but into a new world.
(TRAFFIC HUMS)
This road, only recently built,
has cut through their territory.
The alpha male is cautious.
His own mother was killed on this road.
(HORN HONKS)
He makes sure it's clear before crossing
with the slower members of his family.
If the group is to get what they need...
...they will have to go against their natural instincts...
...and approach humans.
But their new neighbours...
...are friendly.
And they allow the chimps to collect...
...jackfruit,
the largest of all tree fruits.
Jackfruit grow all year round in people's gardens.
And they're more nutritious
than the limited amount of Wild food
the chimps can now find
in what remains of their forest.
But this is a new world...
...and a new relationship.
New boundaries need to be established.
Some of the chimps start to help themselves
to people's crops.
(DOGS BARK)
(SCREECHING AND GRUNTING)
(WINGS FLUTTER)
They have outstayed their welcome,
and the alpha male decides that it's time to leave.
The chimps make this dangerous journey
every day.
But these highly intelligent animals,
our closest living relatives,
have managed, just about,
to carve out a place for themselves
in this changing world.
Animals have maintained
a long-established relationship with forests.
But as we continue
to break our connections with them,
the question is,
for how much longer will they survive?
Surely, the time has come to rebuild them.
DAVID ATTENBOROUGH: Over many years,
I've been lucky enough
to watch chimps in their natural home,
such as here
in the thick forests of West Africa.
YOUNG DAVID: Chimpanzees.
A peaceful scene of jungle harmony.
The experienced male...
...is sitting right there.
But the lives of many chimpanzees
are now changing dramatically.
Here, in Uganda, over the last decade,
they have lost over 80% of their forest home.
They don't live in a protected area.
To survive here,
they have to live alongside the 200 or so human families
who farm here.
LILIAN: The chimps always come from the forest.
They come to eat jackfruit from my land.
They know us by our faces,
as we know them by their faces as well.
To tell the story of this remarkable chimp group,
the Planet Earth team
are working with these residents.
(SCREECHING)
CREW MEMBER: Who was that, Tom?
This one was Araali.
Tom is part of
the Bulindi Chimpanzee and Community Project.
He's been studying the chimps every day
for the last 15 years...
...and has seen the change first-hand.
TOM: Very many things have changed.
When chimpanzees were seeing people,
they would run. Run very quickly and go.
But now they just stand,
because everywhere they go,
they find a person.
Chips are normally tricky to film in the Wild.
But in this human world,
the crew are surprised
by how easy it is to approach them.
CREW MEMBER: There's another one coming up the path.
But back in the forest,
it's a different story.
Here, the chimps seem wary of the newcomers.
CREW MEMBER: (GRUNTS) There's a ditch there.
All the crew get to see...
...is a lot of bottoms.
SAM: This afternoon,
the chimps have been taking us on a wild-goose chase.
They've crossed the river and then they've crossed back,
gone past us While we're in the woods,
and then now they've disappeared again.
When we don't have chimps,
we film goats!
Here, in the chimps' forest home,
it's going to take time to earn the group's trust...
(SCREECHING)
I think they found Moses.
...and get to know one another.
This is Jack.
After two weeks,
things are improving on the ground.
But What will the chimps think of the crew up in the trees?
I can see a bunch of chimp faces looking up at me.
This is a new experience for them.
I doubt they've ever seen a human in a tree before,
so hopefully they accept me.
After hours of waiting...
."success!
RONAN: All the chimps that were on the ground looking up at me
are now happily in the tree,
which is a really good sign that they've accepted me.
It's the first time
that we've been able to see at their level
While they're feeding.
For the crew, it has taken a long time
to gain the chimps' acceptance.
But, in fact, the chimps here have shown
that they can respond quickly
to the presence of people.
DR MCLENNAN: Chimpanzees are highly intelligent.
If you cut down the forest,
well, chimps will start eating human crops.
If you divide their range up with roads and...you know,
the chimps will end up
just learning to cross the roads.
The animals can adapt
to an increasingly human environment.
The question is,
can people accommodate an animal like a chimp?
(SCREECHING)
Chimpanzees can be dangerous.
(SCREECHING)
Living alongside them is a mixed experience.
The local community and the project
have been working together
to try to decrease the impact of these problems.
Over the last eight years,
Lilian and her family
have planted native seedlings on her land
and left her patch of forest to regrow.
LILIAN: If we cut it,
they come and sleep in our houses,
so we should leave that place for them.
If you leave them and you don't disturb them,
they are peaceful animals.
With other residents following suit,
more of the forest is showing positive signs of return.
There is a long way to go,
and the future for these chimps remains uncertain.
But where peaceful coexistence can be built,
there is hope.