In the great Tree of Life,
one branch of the mammals has a particular fascination for us, for we belong to it.
Primates.
Primate hands provide a firm grip.
And forward facing eyes accurately assess distance.
Both are crucial for a lifestyle that began in the trees.
Intelligence among primates can excel that of all other animals.
Primates can solve difficult problems...
..develop thoughts and ideas...
..and build long-lasting relationships.
But most importantly, primates remember what they learn during their lives.
This film reveals how intelligence helps our closest relatives to tackle the many challenges of life.
There are more than 350 primate species on Earth.
Since they first appeared over 65 million years ago,
these clever animals have become adapted to an extraordinary range of habitats.
The Awash region of southern Ethiopia.
A harsh, remote scrubland.
But primates have learned how to make it their home.
Hamadryas baboons are waking up from a night spent high on the cliffs.
These monkeys live in groups up to four hundred strong, with no single leader.
Theirs is a very complex society, made up of dozens of small harems, each governed by a male.
Every morning they leave the safety of the cliffs to find food.
Top-ranking males lead the way.
They can be very severe with their females if there is the slightest misdemeanour.
Despite their individual strength, hamadryas baboons prefer to travel as a troop.
It's safer that way.
On this particular morning, something stops them in their tracks.
Another troop is using these cliffs as a barracks.
More than a thousand baboons can overnight here.
And a rival faction is heading directly their way.
In the chaos of warfare, males settle old scores.
This is also their best chance of stealing females.
When the fighting is over, the harems reform.
Lead males punish any of their females who had dared to stray.
Strict discipline is essential if order is to be maintained.
It's a harsh social system
but it works for hamadryas baboons here on these arid plains.
In other parts of the world, primates have had to organise
their societies in a different way to cope with different challenges.
Mid-winter in the Japanese Alps.
The Kamicoche Valley is the haunt of the most northerly-dwelling monkeys.
To live here you must be able to survive temperatures which plunge to minus 20 centigrade.
The Japanese macaque.
Dense thick layers of fur help to insulate these snow moneys in this testing environment.
But they still feel the cold.
At this time of the year food is scarce.
But macaques are adaptable and clever.
The troop has learnt that this river stays ice-free the year round.
This female knows it's a good place to gather insect larvae
from under the rocks, using her versatile hands and nimble fingers.
In winter, this troop spends most of its time searching for food.
The same underground forces that prevent this river from freezing
bring great comfort to others.
The Japanese Alps were built by volcanoes.
Many of them are still active.
And in a region called Hell's Valley, some snow monkeys have found the perfect winter resort.
A thermal spa,
where the water temperature is a blissful 41 degrees centigrade.
Everyone wants in, but primates being primates,
there are pool-side politics.
This is an exclusive members-only club.
Only the highest-ranking females and infants are allowed in.
Everyone obeys this male, who guards the pool and vets the entrants.
These youngsters, born of the right bloodline, don't know how privileged they are.
Lower ranking individuals are literally left out in the cold.
Japanese macaque society is very divided.
There are those that have.
And those that have not.
And that is a harsh division, because the sixty degrees that separate the steaming water
from the freezing surroundings
can make the difference between life and death.
But by far the majority of primate species
live in warm tropical forests.
Among them are the largest of all.
Gorillas live in stable family groups with just a single leader,
a silverback male.
This one, here in the Congo basin, is the guardian of his family
which includes five females and their infants.
He has the responsibility of protecting them from the dangers
that abound on the forest floor where they feed.
To sustain his huge size, he must consume up to thirty kilos a day.
It's mostly plant food, but western gorillas also enjoy a sprinkling of termites.
The youngsters need to eat far less than their father, so they've got time on their hands.
They like to play for the same reasons we do...for fun.
And it helps build long-lasting relationships.
Their protector keeps a watchful eye on them.
But then...
..it's time for his siesta.
Something shatters the peace.
This silverback's territory is one of the best.
But it has borders with at least eight other gorilla groups.
The sound of chest-beating travels more than a mile through the tangled under-storey.
It's a territorial drum-beat.
Everyone must know who is boss around here.
Other smaller primates are rather more secretive.
One of the most unusual is found in Sulawesi, Indonesia.
It lives among the aerial roots of this strangler fig.
Its ancestors were daytime hunters, but they found that there was less
competition if they looked for food in the twilight.
Now they only stir after dark.
Nonetheless there's a lot of insect food around.
The spectral tarsier.
Tarsiers are the only totally carnivorous primates on Earth.
They've hardly changed in 45 million years.
Their huge eyes can see in even the faintest light.
These eye-balls are so wide they can't swivel in their sockets -
tarsiers have to rotate their heads.
Their mobile ears can detect the faintest sounds.
And their powerful legs enable them to jump 40 times their own length.
The family group fans out to hunt.
Prey is not hard to find.
But the tarsiers must be watchful.
For a primate just five inches tall, life in the forest is full of danger.
- The male sounds the alarm. - CHIRPING
And everyone retreats.
Back in their family tree, the senior male and female send out piercing calls.
These calls guide any stragglers home,
and there they renew the family bonds.
Good communication is one of the hallmarks of primate society.
Few communicate more musically than lar gibbons
in the forests of Thailand.
Their songs carry for many miles across the canopy,
proclaiming that this piece of forest is theirs.
Most primates have excellent colour vision, and colour too can be used in communication.
Adult Phayre's leaf monkeys might seem rather drab.
But not so their newborn.
Bright orange fur makes the babies very conspicuous,
so the adults can easily keep an eye on them.
Close friends and relatives are eager to help the mother with baby-sitting.
It's a good chance for the younger ones to practice parenting.
As a result, a baby is never left on its own for long.
When it's a few months old and more independent,
it will turn the colour of its mother and blend in with the group.
But until then, it can't be ignored.
Smell is of particular importance to the primates that live in Madagascar -
the lemurs.
They have pointed snouts and wet noses.
These are ringtail lemurs.
The males have sharp pads on their wrists with which they scratch the trunks of young trees.
Glands on their wrists impregnate the cut bark with a pungent smell that acts as a territorial marker.
Females make smelly marks in their own way.
This one's scent carries another signal as well as the territorial one.
It tells males that she's coming in to heat.
But she will only be sexually receptive for 24 hours or less.
So tensions run high among the males.
Amid the commotion, some males sneak off.
They have anointed their tails with scent and waft it towards her in an attempt to persuade her to mate.
She's ready...
but fussy.
This male adds more of his wrist gland perfume to his tail.
It seems to work, for they leave the party together.
And he wafts his way to victory.
A willingness to mate is a relatively straightforward message.
But primates are capable of much more complex communication.
It starts between a mother and her baby.
The rainforests of Sumatra.
This female orang-utan is forty-two years old.
Her third child, a six year old daughter, is still with her.
Orangs look after their children for longer than any other primate...
except ourselves.
It will take her nine years to teach her youngster
everything she needs to know about this complex tree-top world.
She must learn how to collect ants and termites.
How to identify at least 200 kinds of edible plants...
and how to avoid the poisonous ones.
And how to judge when fruit, like this durian,
has ripened to perfection.
Her child must be able to judge which branches can carry her weight.
And which insect nests are safe to raid.
Building up a complete guide to the foods of the forest is a long process.
Her lessons, of course, aren't limited to food.
There are other crucial skills she must learn if she is to survive in the tree tops.
Building a secure nest in which to spend the night, for example, takes years of practice.
And this is, of course, a rainforest.
THUNDER RUMBLES
So all orangs must learn how to make a shelter early in their lives.
It rains almost every day, so this six year old has already had plenty of practice.
She might live to be fifty years old and if she too becomes a mother,
she'll pass on all this expertise to her own children.
Remembering your lessons is a vital part of primate life.
It's not just learning how to exploit your environment.
Just as important is knowing when to do so.
This is Africa's Cape peninsula.
It's the furthest south that monkeys have managed to settle.
There's a wide range of plant food here, but because the soil is so poor in nutrients,
Chacma baboons find it difficult to get the range of sustenance they need,
however much they eat.
So they have had to become quite adventurous in what they will tackle.
The waters around the Cape are among the richest in the world.
And the wily baboons have become tidal experts.
If you rely on the tides to expose your food, you have to work to fairly tight schedules.
Every two weeks, on the lowest spring tide, there's a chance to collect something really special.
What they've been waiting for is hidden among the fronds of seaweed.
Shark eggs.
Each one is only a tiny mouthful, but there are lots of them
and they're so nutritious it's worth the trouble.
But the baboons can't stay long...
the tide is turning.
So now they switch their attention to the main course of the day... mussels.
This delicacy is exposed every day, by every tide.
Baboons have powerful jaws and huge canines...
ideal for cracking shells.
Timing is an essential skill if you are to harvest
all the food that becomes available at one time or another around a coast.
Some foods, however, are only available to those who have skilful hands and sharp intelligence.
On the coast of Costa Rica, among the mangroves,
live some of the most intelligent monkeys in the whole of the Americas.
White-faced capuchins.
They too have learnt to work the tides.
They are after clams.
But capuchins are quite small and don't have the brawn to open such shellfish.
But they do have the brain,
and they've devised an ingenious way to solve the problem.
They hammer the clams.
They are not trying to crack the shells, all this pounding
and rolling has another purpose, to tire the muscle with which the clam is holding itself shut.
Eventually the clam can hold out no longer,
and the capuchin gets its reward.
Trial and error may have been sufficient to solve this particular problem.
But one of their cousins in Brazil has taken things a step further.
Brown-tufted capuchins combine manual dexterity with considerable intelligence.
And they have learned to use tools, hammer stones with which to open palm nuts.
Some of the stones are nearly half the weight of the monkey.
Without a tool, opening these nuts would be an impossible task.
Tool-using was a major breakthrough in primate evolution.
And nowhere is it more convincingly displayed than here in the forest of Bossou in Guinea, West Africa.
PANTING AND WHOOPING
Chimpanzees in this small community of thirteen individuals use tools in a variety of ways.
The most delicate is the way they use a twig or leaf stem
to dip for ants.
Some of their skills are unique to this particular group.
One of these involves stripping a palm leaf frond
and using it like a pestle to mash up the nutritious palm heart.
This four-year old is learning fast.
She needs to.
If chimpanzees haven't learned particular skills by the age of 8,
they never seem able to acquire them.
The most impressive skill of all, which involves nimble fingers,
hand-eye coordination and intelligence, is nut cracking.
Chimpanzees have gone a stage further than capuchins.
They have learned how to carefully position the nut on an anvil and to judge how much force to use
in order to crack the shell but not smash the kernel to pieces.
Their use of tools is both efficient and precise.
This eleven year old female has an anvil, but can't find a hammer.
She approaches a male to see if he will lend her his.
He obliges.
Chimpanzees can show great kindness
and compassion.
Sharing.
Experimenting.
Empathy.
Planning.
Intelligence.
Teaching, and learning.
Behaviour so characteristic of us higher primates.
We are the most inventive and innovative of all primates.
Just one branch of a large and extended family.
A family which has refined the ability
to develop and pass on individual learning to the next generation.
A family which is built on strong bonds between mother and baby.
A family with which we share so much.
To film the very best primate behaviour,
the Life team had to use all their primate ingenuity and adaptability.
And in doing so, they discovered an extraordinary affinity with our extended family.
Especially with a great ape with who we share almost 99% of our genes,
the Chimpanzee.
He was completely asleep just then, so you just, just rocking to the side as if he might just fall off
the branch, you could see his lips were twitching like he was in a deep dream, that was really beautiful.
Chimpanzees are our closest relatives.
Justine Evans spent almost a month with them in the forest of Guinea to film their use of tools.
The chimps have disappeared off down there,
they're gonna cross over into another area of forest and hopefully start using some tools.
Go and use tools, that's what we're here for.
Chimpanzees have to accept you.
If they don't want to be filmed, they'll simply disappear.
Justine needed the expert guidance of Tatyana Humle, a primatologist
who's spent more than ten years studying these individuals.
So when we see them always keep calm and don't stare straight into the eyes.
Have you ever had problems with them coming right up being aggressive?
No, never, never. I mean it's pretty rare, so...
I don't know what to expect cos I've never seen them in the wild before so it's a first for me.
So just always stay, stay calm and if one of them walks by really close, just ignore them.
One particular young male might throw sticks,
ignore him as well, it's like he's like a kid
and he just wants attention so he'll just keep doing it.
We've got to put these face masks on in case we pass on any infectious diseases.
Quite a few chimps have died in the past from respiratory diseases
in other study sites, so it's very important.
Justine was finding her way with the chimps.
But it would take time.
It's never easy anticipating their behaviour.
I'm trying to get ready really quickly because we're expecting
some chimps to come down the path straight ahead of me.
It'd be lovely if they'd merge out into this clearing,
cos it's really difficult to see through all this foliage.
Tatyana and her team were invaluable,
they introduced Justine to the chimps' different habits and characters.
Soon the natural inquisitiveness of the chimps overcame any worries they might have had of Justine.
In fact, they seemed fascinated by her, and the tools of her trade.
But it was their use of tools that Justine was here to film.
And this was her first good opportunity.
As I filmed them fishing for ants I was amazed by their dexterity.
But holding focus in such low light really tested my own coordination to the limit.
Now she's moving away.
She's moving.
It's been all go today, it's not over yet,
if we can get out of here into an open,
more open area we'll actually have enough light to film by
cos the sun's still up, but I don't know.
Although Justine's main goal was to film tool use,
there was another piece of behaviour she really wanted to capture.
Buttress root drumming had never been filmed here before but she was always just a bit too late.
Back at yet another buttress in the hope that we might
get some sort of buttress drumming, but it's started raining
which is an absolute pain.
It's a waiting game.
Just staking out a couple of really big trees that have got very large buttress roots
in the hope that a male will come down and drum on them.
The drumming always happens somewhere else, and apparently,
it's usually the males that sort of sneak off to go and do it,
it feels like a bit of a long shot at the moment.
I've have to have some patience.
The thing about chimps is that, like most primates, you can't always predict
what they're going to do, when they're going to do it, or where.
You've just got to keep with them.
A different type of sound brought Justine back to her main mission.
Nut cracking.
This was the key sequence Justine was here to film.
Filming the chimps using tools made me realise just how close to them we are.
I felt so similar to them.
By the end of our filming trip I was able to recognise
most of the individuals in the group and had begun to understand their different personalities.
For me, the most poignant moment of all
was when the male the scientist called Clay lent a female his tools.
I know that primates are very social animals
but seeing this act of generosity was something that I'll never forget.
Just before we left, the chimpanzees finally put on the display that I'd been hoping for.
In the great Tree of Life,
we and chimpanzees went our separate ways about six million years ago,
but they remain our closest living relatives.