In the heart of Africa, straddling the borders of Rwanda, Uganda and Congo
lies a remarkable mountain kingdom.
It's home to the world's last 700 mountain gorillas.
For over 50 years, they've been caught in the crossfire
of a brutal civil war, fuelled by an ever-increasing human population.
Yet still they survive, under constant surveillance
from a dedicated group of people.
A species in intensive care.
Our cameras have been given privileged access
to these amazing animals, revealing their secret lives.
We'll experience the challenge of keeping an extended family together,
the joy of growing up wild in a rainforest playground,
the love of a father for his abandoned child.
And above all,
the extraordinary battle to save one of our closest relatives.
For a million years, the Virunga Volcanoes
have dominated the heart of Africa.
A volatile presence in a volatile region.
On their lush slopes, nourished with centuries of volcanic ash,
lives the world's largest single population of mountain gorillas.
Since Dian Fossey started her pioneering research
here in Rwanda over 40 years ago,
they've become one of the planet's most cherished animal communities.
April is a dangerous month in the Rwandan Virungas.
The long rains arrive, and the gorillas head down
into the bamboo zone on the very edge of their protected area.
It can be a perilous journey.
The bamboo contains illegal snares set for forest antelope and pigs,
but potentially lethal for gorillas.
It's a worrying time for research scientist Felix Ndagijimana,
who has trekked through the mist to a height of 4,000m.
(GRUNTING)
Continuing Fossey's work, Felix watches and records
every detail of the gorillas' lives so they can be effectively protected.
Today he's on the trail of silverback patriarch Cantsbee...
..the leader of the biggest gorilla family in the world.
This 46-strong group contains female consorts, junior silverbacks,
adolescent blackbacks...
...and a tiny newborn baby,
just hours old.
At 32, Cantsbee is one of the most successful silverbacks recorded
since the research programme started in 1967.
He was even named by Dian herself.
Everybody thought that Puck, the mother of Cantsbee, was male
until the day she gave birth.
And when they told Dian Fossey, she said, "It can't be."
So, from that day on, the name of the infant - Cantsbee.
Three decades on, the bloodline continues.
THUNDER
The clouds are building.
Soon Felix will follow the family on the difficult journey
down the slopes towards the bamboo, recording every move they make.
This privileged insight into their world is possible
only because of Fossey's pioneering work with a process known as habituation,
in which humans spend more and more time with the gorillas
until they're completely accepted.
40km north of the Virungas lies Uganda's Bwindi Impenetrable Forest.
It's home to the rest of the world's mountain gorillas...
..and to a scientist carrying the work of Dian Fossey into new territory...
...American Martha Robbins.
Bwindi contains only 300 mountain gorillas,
and there are another 380, 400 in the Virunga Volcanoes.
We could put the entire population of Bwindi onto a jumbo jet.
It might be difficult to get them onto a jet, but...
And when you think about how few there are,
every birth really does matter, and every gorilla is very important
to maintaining this very unique, special population.
Like Fossey in Rwanda, Martha has carefully habituated
mountain gorillas to her presence.
Now, after a dozen painstaking year
the 14 animals in her research group trust her completely.
At the moment, she's particularly interested
in a 15-year-old junior silverback, Marembo,
an ape at a crossroads in his life.
Marembo's really at that age where he needs to start being
a big, mature silverback, but at the same time, he still likes to play.
One of the things that's really nice when you see gorillas
of very different age playing
is that the older ones really temper themselves down.
They'll play quite gently with the younger individuals.
Marembo isn't a child any more.
For several weeks, he's been spending more and more time alone.
He seems ready to break from his family and try life on his own.
But it's a big decision.
And like a human teenager leaving home for the first time,
he feels torn.
The Rwandan town of Ruhengeri at the foot of the Virunga Volcanoes
is the centre for all gorilla operations.
The National Park headquarters is here.
And the Karisoke Study Center...
..a hive of activity for trackers, field staff
and research scientists like Felix.
It's also the headquarters of the Mountain Gorilla Veterinary Project...
..a team of skilled specialists closely monitoring
the health of every known gorilla.
Their work extends across the three countries
that share the world's last 700 mountain gorillas.
On the Rwandan side, the biggest priority is little Umoja.
She's a small three-year-old female
and never strays far from her father, Kwitonda,
one of the oldest silverbacks in the National Park.
It's a touching relationship,
but the youngster's life hasn't been easy.
Recently, as Kwitonda tried to prevent a rival male from stealing his females,
Umoja was caught in the crossfire and badly injured.
Her life was saved only by the time intervention of vet Magda Braum.
Here was Umoja, with a badly injured wrist,
and intestines are hanging out of her tummy.
She was bitten and she was thrown high in the air,
fell down, was bitten again.
So they were pretty sure that she was dead.
Magda operated on the spot, and Umoja was returned to her mother,
who gently nursed her back to a fragile health.
Because what we've done was important, but I think
without what she has done, there was absolutely no chance of surviving.
But this wasn't the end of Umoja's problems.
Before she'd completely recovered,
her mother deserted the group for a rival silverback...
..leaving Kwitonda as Umoja's sole carer.
A female gorilla would normally give round-the-clock care
to her offspring for up to five years.
This is a big job for the male.
The gorilla vets and the National Park team
are now keeping an intense watch on the abandoned infant and her father.
They know that as the rains arrive and the nights become colder,
she'll miss the warmth of her mother
In the Virungas of Rwanda, the world's largest group of mountain gorillas,
led by silverback Cantsbee, are heading down the volcano
towards the bamboo zone on the edge of their protected area.
As the clouds roll in, it will bring rain, prompting fresh shoots on the bamboo.
But there are dangers here.
Beyond the bamboo is the most densely populated area in Africa,
with an average of 350 people per square kilometre.
The gorillas are encircled by humanity.
The two forest islands of Bwindi and the Virungas
are under enormous pressure.
When the gorillas get close to people, they're exposed to human diseases...
..and the risk of being caught in an illegal snare.
Gorillas go to the bamboo zone twice a year,
at the beginning of the rainy seasons, so in April and in December.
So this is when they leave other areas where they range
to feed on the bamboo, which is one of their favourite foods.
The gorilla patriarch must be careful.
The danger from undetected snares is high.
With 46 gorillas to protect, he's got a tough job on his hands.
He has support from four junior silverbacks...
..and eight feisty younger blackback males...
GORILLAS SCREAM
..not all of whom can be trusted.
This young blackback is breaking the rules.
It's a privilege normally reserved for the dominant silverback.
But Cantsbee needs to reward his lieutenants,
and sex is a powerful incentive
to keep them in line and the group together.
The dominant silverback needs to concentrate on the dangers
from the outside world.
The family are entering the bamboo zone...
..and they have company.
Fortunately, in this case it's the National Park's anti-poaching patrol,
acting on a tip-off that snares have been set in this area.
Most of the snares are actually found in the bamboo.
They are very, very difficult to spot.
They have to, you know, look very carefully to find these snares.
We destroy around 1,000 snares each year.
People come in the forest and set snares for other animals,
for buffaloes, for antelopes, but gorillas end up getting caught in those snares.
Poaching has always been a problem in the Virungas.
In 1977, Dian Fossey's favourite gorilla, Digit,
was murdered and decapitated by poachers as he tried to defend his family.
Things have improved since then, but poaching is still a big problem.
In Uganda, teenage silverback Marembo and most of his group
have moved into the trees.
Unlike their cousins 40km away in Rwanda,
these gorillas spend a lot of time up here,
and it's where they find much of their food.
That means climbing is an important skill to master.
Junior silverback Marembo is on the edge of the family,
his eyes fixed on the dominant male.
In a group of this size, there's only room for one leader...
..and a teenager can feel increasingly marginalised.
Males have sort of two strategies as to how to become the leader of the group.
They can either leave the group and become a solitary male
and try to attract females and form their own group, or they'll try to become
dominant from within the group, where slowly, over time,
they'll try to outrank the dominant male.
Mating rights are monopolised by the dominant silverback...
...and since the leader has no real need for him in the group,
Marembo isn't permitted access to receptive females.
(It's quite likely they'll mate maybe once every hour,
(once every hour and a half, two hours, today.)
If the junior silverback wants to pass on his genes,
his best option is to leave.
In Rwanda, abandoned infant Umoja stays close to her father, Kwitonda.
Since her mother left the group for another male,
she's become completely dependent on her remaining parent.
Kwitonda is an experienced silverback,
but he's relatively new to Rwanda, having crossed the border from Congo
with his family six years ago.
The land he left behind has seen much strife for gorillas and people.
In 2007, a gorilla family was brutally murdered here...
...their deaths almost certainly a result of the fierce competition
for the forest's precious resources.
Many of Kwitonda's family bear the scars of war.
Missing fingers and limbs are the legacy of a time spent in a forest
bristling with snares.
But at the moment, the main concern for the silverback -
and for the veterinary team that monitors her - is three-year-old Umoja.
An infant of this age should be with her mother.
Almost every life skill needed to survive in the forest
is taught by females in an education lasting at least five years.
A three-year-old should also keep a close physical connection
with its mother, who will shield it from the extremes of the Virungas' weather.
The quality of her father's childcare
could make the difference between life and death for Umoja.
A storm is brewing above the Virunga Volcanoes in Rwanda.
It can rain here at any time,
but from February to May, it pours almost every day.
On the lower slopes of the volcanoes the stands of bamboo
are already producing new shoots.
Cantsbee must remain vigilant.
His 46-strong family is within metres of the park border
and in danger from illegal snares.
For now, though, he eats.
It's something a gorilla needs to do for at least five hours a day.
Bamboo on its own is too rich for gorillas.
They need to mix it with other plan or they'll get diarrhoea.
Bindweed is another popular delicacy
Cantsbee rolls it into a neat wrap before tucking in.
But this is a surprisingly tricky skill to master.
CHOKES
You must remember to keep the sticky bits on the inside.
It's five in the afternoon, and the temperature's dropping fast.
The weather is closing in.
Adult gorillas rely on their shaggy coats
to keep them warm in the damp high altitude.
But infants need a mother's embrace,
and that's one thing three-year-old Umoja doesn't have.
Since her mother left, she's been in the sole care of her father, Kwitonda.
But the park's veterinary team are still very concerned.
The pair are under constant surveillance.
Mountain gorillas care for other family members
in an extraordinarily loving way.
The bonds between dominant males and their offspring
are the most powerful of all, and a mature silverback
will go to incredible lengths to protect his genetic future.
Now Umoja must survive the first stormy night of the rainy season alone.
At three years old,
Umoja should be getting lessons in nest-building from her mother.
But since she left, only Kwitonda has been able to help her.
For the older, more accomplished gorillas,
branches are folded over to make fresh springy beds in the trees.
This gets them away from the cold ground
and puts a whole range of foods within reach
in case they get hungry in the nigh
But it's a skill Umoja's father can't pass on.
He's too heavy for the trees and nests on the ground.
THUNDER
While the other infants snuggle up to their mothers,
Umoja struggles to complete a nest of her own.
As the storm approaches and the light fades,
Umoja is ill-equipped for the harsh weather.
THUNDER
This is no night for a three-year-o gorilla to be sleeping alone.
The rains have also arrived in Uganda,
where scientist Martha Robbins has noted a significant development.
Young silverback Marembo has vanished.
He's made the brave decision to break with his family and strike out on his own.
A new day dawns clear and bright in Rwanda.
It's 6am, and the veterinary team
is making its way back towards the spot where Kwitonda's group spent the night.
The whole team is worried about his motherless daughter, Umoja.
Gorillas often wake late during the rainy season.
All around, mothers and their infants emerge from their nests.
But there's no sign of Umoja.
GRUNTING
Her silverback father, Kwitonda, is one of the last to wake.
His huge bulk has kept him warm through the long, wet night,
and he seems reluctant to leave the leafy nest.
He's not alone.
Umoja is at his side.
The motherless infant must have climbed in during the long, wet night
to share her father's warmth.
Umoja gently grooms her father, an illustration of the powerful bond
that the pair are building.
The little gorilla still has difficult times ahead,
but Kwitonda is growing into his roll as a hands-on father.
In Uganda, there's still no sign of Marembo,
the missing junior silverback.
Martha Robbins temporarily abandons her search
to travel to the far side of the forest.
Here, a new family of gorillas are being habituated.
Getting gorillas used to humans is a long and difficult task.
GORILLAS SCREAM AND GRUNT
They're not naturally aggressive creatures...
..but they won't tolerate people if they think they pose a threat,
as the park staff here know only too well.
You don't know what to expect from their group.
They come charging with all their teeth out,
and that's the silverback, usually.
It comes, the dominant silverback, because it's trying to protect the group.
This group demands caution.
At 34 strong, they're the largest family in the forest,
with no less than four huge silverbacks.
Martha and the team must approach with care.
Aaah!
They move in, making reassuring noises.
THEY GRUNT
The family is now just a few metres ahead.
GORILLAS SHRIEK
That's an alarm bark, a fear bark,
so there are some quite close.
After the first aggressive reaction, the mood calms.
The team move forward.
They're all watching us all the time.
It's like if you have new visitors or strangers into your house,
you'd be very wary of what they were doing.
The photographs record each gorilla's unique features.
Eventually, they'll be given names too.
Martha will advise the National Par team if and when the gorillas
are ready to meet visitors.
But for that to happen, they must be calm and confident.
The gorillas are used to the uniform. To these nice uniforms.
So now we have to get, like, two, four tourists,
so that they try to get used to different faces with these uniforms.
HUMANS GRUNT
GORILLA SCREAMS
The reaction of a mature female suggests
they aren't quite ready for visitors just yet.
But over the next few months, the gentle habituation process will continue
until the silverback is as relaxed with humans as Kwitonda and Cantsbee.
Tourist visits have become the life-blood of gorilla conservation
in the forest and the volcanoes.
It was an idea Dian Fossey initially rejected as being too intrusive.
But over the years, carefully managed tourism has provided Uganda and Rwanda
with the revenue to look after the gorillas
and a critical income for the people
many of whom live on less than a dollar a day.
In Rwanda, single father Kwitonda and his daughter
are crossing the park's boundary wall.
Motherless infant Umoja follows in her father's wake,
ready to taste a new food.
The three-year-old is now fixed on every move her father makes.
But there's a difficult road ahead.
Half of all infants fail to reach maturity,
and the lack of a mother's care means the odds are stacked against Umoja.
The attraction here is eucalyptus sap, which gorillas find irresistible.
Just 5km away, Cantsbee and his huge family
have also crossed the wall.
But there's a problem.
Felix has found a gorilla that's been left behind.
She's lying alone, curled up in a ball.
Nyandwi, Cantsbee's sister.
She's laying down and not doing anything,
and this is, like, not a feeding session, everybody's feeding again,
you can see that she's left behind when everybody's left, so she is perhaps sick.
Separated from her family, she's vulnerable.
Cantsbee's sister is in the heart of the dangerous bamboo zone
with no protection.
Since Felix can't stay in this part of the forest after dark,
he can only hope that the female gorilla comes to no harm overnight.
Not far away, the anti-poaching team prepares for a night under the stars.
For many hours, they've swept the park for snares.
In her forest home in Uganda,
Martha records another day without the missing junior silverback, Marembo.
At daybreak in Rwanda, the anti-poaching team are once again
sweeping the park for the illegal snares that can prove fatal to gorillas.
But, for one young female, it may be too late.
The sick female, sister of gorilla patriarch Cantsbee,
managed to rejoin the group.
But as she passed through the bamboo zone,
she caught her arm in a freshly laid snare.
If it isn't removed, she could lose the whole limb
and possibly even her life.
Fortunately, Dr Lucy Spelman from the Mountain Gorilla Veterinary Project
has joined the team.
Before the snare rope can be cut from the gorilla's wrist,
Dr Spelman needs to immobilise her with an anaesthetic dart.
That's not an easy task.
Intervening in a group of this size and strength is notoriously difficult.
Silverback Cantsbee is supported by four huge lieutenants,
all willing to put their lives on the line in defence of the family.
THEY GRUNT
If they become suspicious of Dr Spelman and the team, they will attack.
THEY WHISPER
This is a serious operation, and each member of the team is thoroughly briefed.
But, for the procedure itself, Dr Spelman must go it alone.
Fortunately, she's a wildlife vet with years of gorilla experience.
Dr Spelman is now within a few metres of the group.
Cantsbee rests further down the slope, while his injured sister sits alone,
the rope snare clearly visible on her wrist.
HE WHISPERS
SHARP SNAP AND AGITATED GRUNTING
Dr Spelman's taken the shot, but the young gorilla moved at the last minute
and hasn't received the anaesthetic.
Many hours of careful manoeuvres now lie ahead
if the young gorilla's life is to be saved.
In Uganda, Martha Robbins is on the trail of missing junior silverback Marembo.
He's now been absent for a week,
a sure sign that he's finally made the break from his family.
The group have made their way into the swamp at the heart of the forest,
but there's no sign of Marembo or the dominant silverback.
The leafy curtains part, and a gorilla appears.
It's the dominant silverback, and he's looking agitated.
Could his mood be linked with Marembo's disappearance?
For now, the group has a single silverback.
Now Marembo will eke out the life of a lone wanderer
in the leafy depths of the forest, until, hopefully, securing a family of his own.
For Martha, it's a poignant moment.
She's known this young silverback since he was a playful juvenile.
Yet she can't help hoping that he may yet return.
I bet we'll see him a little bit over the next few months.
It's very difficult to be a successful silverback.
He's got a few rough years ahead of him,
being a solitary male and trying to acquire females,
but I think he's got a fair chance. We'll have to wait and see.
In Rwanda, Felix is heading out early.
He's hoping to catch up with Cantsbee's sister,
who was caught in the illegal snare.
There's good news. Dr Spelman managed to anaesthetise the gorilla
and remove the snare.
The family is heading back to the summit of the volcano.
There's a familiar gorilla up ahead.
It's Cantsbee's sister, and she looks healthy.
This is Nyandwi here, and she's doing well since the snare was removed.
She's back in the group, she's feeding, she has no problem at all.
It's a great outcome for the team.
A mountain gorilla has been saved,
and Cantsbee's family is still 46 strong.
Further down the volcano, single father Kwitonda has also decided
to lead his family away from the bamboo.
Following the silverback is an unfamiliar female.
She sits removed from the others, nursing a tiny baby.
This should mean certain death for an infant new to the group.
Any dominant silverback would kill a baby that was not his own.
Yet Kwitonda has not reacted.
But this female is no stranger.
It's Umoja's wayward mother, who deserted Kwitonda for a rival silverback,
but she left pregnant with his child.
Now she's returned to seek his protection.
The hands-on father has a new son, and Umoja has her mother back.
How things develop now remains to be seen.
But one thing is certain...
..the bond between the little gorilla and her father, Kwitonda,
will remain strong for the rest of their lives.
Next time on Mountain Gorilla...
..the last stand of the silverback king.
Titus, the oldest silverback in the Virungas,
faces his destiny in a brutal showdown with a rival male.
He struggles to protect his dwindling family
as the hostile intruder piles on the pressure in a war of attrition.
Felix can do nothing but watch as the realisation dawns -
Titus's challenger is his son.