♪♪ -They travel hundreds of miles on paths carved by their ancestors.

They carry irreplaceable knowledge, and they embody a world of contradictions.

[ Elephant trumpeting ] Breathtaking power and remarkable sensitivity.

With tusks each weighing over 100 pounds, these special males have been nearly obliterated by human greed.

Fewer than 30 of these super tuskers remain in all of Kenya.

[ Elephant rumbles ] Three magnificent tuskers, each on his own path, carry us into a world rarely glimpsed.

Highly social, even affectionate.

Their alliances run deep.

This is a brotherhood.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ -These tusks bear 34 million years of evolution.

[ Elephant rumbles ] ♪♪ And etched into them is a lifetime.

For over half a century, this elephant, known as Craig, has followed the tracks of his ancestors.

♪♪ ♪♪ Tasks that reach the ground are rare, but Craig is far more valuable than the ivory he carries.

He is a keeper of knowledge.

He knows the migratory routes carved by generations.

He knows where to find food and water when the land is parched.

Tuskers like Craig are guardians of an ancient lineage.

This wise old tusker has just survived a deadly drought.

And now Kenya is green again.

♪♪ ♪♪ Elephants are pouring in from miles around.

[ Elephants rumbling ] ♪♪ Families are gathering on the open plains of Amboseli.

In this time of abundance, elephants can reunite and renew their social ties.

♪♪ ♪♪ The grasslands are flush with life and scattered reminders of those who couldn't hold on until the rains arrived.

No species escaped.

Mothers lost young.

Families lost matriarchs.

For those who survived, this moment of celebration holds the promise of new life.

♪♪ The springs and water holes are full.

For this immense gathering of the matriarchy, it's a time of pure joy.

♪♪ ♪♪ ♪♪ The matriarchies, where their sisters and daughters and young sons are the cornerstone of elephant society.

But they are only part of the story.

The rest are miles away and well aware of the gathering.

[ Elephant rumbles ] Elephant rumbles vibrate through the air and ground, carrying messages from afar.

Esau traveled through the night.

At 33, this magnificent tusker is not yet fully grown, but already His tusks nearly touch the ground.

They're a genetic gift from his parents.

He was born here in Amboseli, but he's here now for only one reason.

He is ready to mate.

Esau is just entering his breeding prime, and his hormones are raging.

He is in musth, a heightened sexual state.

♪♪ Testosterone is surging through his system.

Pheromones stream from his swollen glands, and he leaves a scent trail of pungent urine.

As impressive as he is, it's still years before he'll reach his peak as a breeding male.

While Esau broadcasts his status, he listens for others.

Through sound and scent, he's aware of a much larger male to the west.

On the far boundary of the park, another tusker is in musth.

♪♪ At 44, Pascal is in his breeding prime.

He is massive, built like a tank with hulking shoulders and stout tusks.

♪♪ His right ear was damaged in a long ago battle, or so it's believed.

♪♪ He's been in Amboseli for the past month searching for females ready to mate.

♪♪ He's a highly successful male, a favorite among the females.

[ Elephant rumbles ] Few males would dare challenge Pascal when he's in musth.

[ Elephants rumbling ] Pascal is at his peak.

Miles away, Esau will continue to monitor and keep a safe distance from Pascal.

Key to Esau's survival is knowing his strength.

He must pick his battles carefully, because on this playing field, other males are also in musth, and they're looking for mates.

They're listening.

They're searching for scent.

And they're pumped with testosterone.

♪♪ At every moment, stories are playing out all across the plains of Amboseli.

This labyrinth of swamps and savanna is a haven for wildlife.

♪♪ ♪♪ The swamplands of Amboseli are fed by the waters from Mount Kilimanjaro.

Africa's tallest peak sits just across the border in Tanzania.

This vast ecosystem contains Amboseli National Park at its heart, but it spans over 3,000 square miles, reaching across Kenya's border.

Elephants depend on this entire ecosystem.

Grasslands alone aren't enough to sustain bulls like Esau.

They need woodlands to support their massive bodies.

To find them, they travel well-worn paths that often lead beyond protected areas.

And sometimes those paths cross invisible boundaries.

Just across the border, in Tanzania, trophy hunting is legal.

With his hyper sense of smell, Esau is following the scent trail of a family with several females.

[ Elephants rumbling ] He'll check to see if any of the females are in estrus, a time when they're receptive to mating.

This one has a youngster in tow.

Kibo is 4 years old.

He'll study Esau's every move.

Females have only a two-day window of peak fertility.

She allows him to test her, and Kibo moves in to catch the scent.

Esau allows Kibo to move even closer.

This is how young males learn.

This is how Esau learned.

Despite his size, Esau is extremely patient with the youngsters.

But he's not so tolerant of a nearby bull.

It's the musth manifesto to maintain supremacy.

[ Elephant trumpets ] Esau's performance has inspired the boys.

♪♪ Even at this age, they're hard-wired males, full of bravado and bluster.

These boys are building alliances that will serve them on their journey ahead.

Like Esau, they will face a gauntlet of tests.

[ Elephant trumpeting ] Searching for females while fending off males, holding their place in the hierarchy, all while simply surviving.

♪♪ Miles away, Pascal is also searching for receptive females, but in this vast landscape, they are few and far between.

He won't bother checking this young mother.

She won't come into estrus for a year or two, if her calf survives.

The odds are tough for male calves.

1 in 10 won't make it through their first year.

Males grow faster and need more milk.

In times of scarcity, many don't survive.

Males who make it to 44, like Pascal, are rare and precious, not only for their genes.

The presence of an older male, no matter how brief, is invaluable.

Pascal can teach these boys what their mothers can't.

♪♪ Play fighting is key to male development.

These boys are forming their future peer group.

It's a time to socialize and bond.

♪♪ ♪♪ They challenge and test their strength.

♪♪ Sizing up their opponents, they sharpen their skills for the battles ahead.

But elephant girls are different, even as infants.

She'll join in the game, but only for a moment.

Then it's back to mom.

♪♪ ♪♪ It will be years before these teenagers experience their first musth.

For now, it's still just a game.

On the eastern boundary of the park, Craig, one of Amboceli's oldest and most revered males, is taking advantage of the grasses.

He's still thin from the recent drought, but he's been putting on weight since the rains arrived.

Craig is considered a super tusker, a rare giant whose tusks each weigh more than 100 pounds.

He's one of fewer than 30 in all of Kenya.

Like other tuskers, Craig uses his ivory for protection and to access food.

What should be an asset became a liability when hunters and poachers targeted bulls with the largest tusks.

Amboseli National Park offered a safe haven.

It continues to be a rare stronghold where super tuskers like Craig can still exist.

Craig is a living legend, as is every tusker following in his footsteps.

♪♪ On the salt flats by Lake Amboseli, another tusker has fulfilled his mission.

Pascal is following a female with a crooked tail.

She's at the peak of estrus, and they've been mating for the past two days.

But opportunistic males are circling.

Pascal guards her from behind.

Until she falls out of estrus, he'll keep the other males at bay.

Pascal's mere presence is so intimidating, a subtle gesture or a musth rumble is often all it takes.

[ Elephant rumbles ] [ Elephant rumbling ] But even the highest ranking males do need to be cautious.

Pascal's musth cycle is coming to an end.

A younger male at the peak of musth could soon challenge him and win.

[ Elephant rumbling ] Esau has caught wind of a competitor to the south.

Even from a distance, he can read the scent.

The other male is also in musth.

Esau listens for further clues.

♪♪ Adult males never take fighting lightly.

It can lead to injury or even death.

It's crucial to size up your opponent to calculate the risk.

As they approach, they assess.

The other male has a similar build, shorter tusks, but in good condition.

♪♪ ♪♪ If neither retreats, there will be a fight.

♪♪ [ Elephant rumbling ] [ Elephant rumbles ] ♪♪ Esau claims victory and the loser retreats.

Esau trails him.

A most amazing thing has happened.

Esau has forced the loser out of musth.

It just shut off, like a faucet.

He's become submissive.

To be certain, Esau tests the defeated for signs of testosterone.

Satisfied, he allows the loser to retreat.

♪♪ ♪♪ There's now one less male to contend with.

♪♪ To make sure there was no damage, Esau checks his precious tusks.

Amidst the dramas of Amboseli, one ancient being stands tall against the horizon.

For nearly 500 years, she has borne witness to life's ebbs and flows.

She is home, shelter, shade, even sustenance.

Creatures of the night find calm within her thorns.

Her trunk is worn smooth by generations of elephants.

They leave, sent messages for others on and all around her.

She is a hub of information and opportunity.

There's an order in this natural world.

It is full of unlikely alliances and hidden possibilities.

For hundreds of years, this ancient acacia has witnessed Amboceli's dramas, large and small, and the constant tide of elephants as they come and go.

♪♪ Pascal is leaving the park.

♪♪ Despite his heft, he carefully avoids disturbing the bones of another creature.

♪♪ Elephants display a remarkable respect for both life and death.

♪♪ With musth behind him for another year, he heads east, on a journey that will take him from the safety of Amboseli into a landscape that is rapidly changing.

Land is being reshaped by human hands.

What once belonged to wildlife is falling prey to the plow.

Highways are carved across age-old elephant paths.

♪♪ ♪♪ Elephants are intelligent and adaptable, but change is coming quickly.

♪♪ ♪♪ 20 years ago, this town was little more than a cluster of Maasai homesteads.

As it grows, it eats into land where Pascal's ancestors once roamed.

Within this rising sea of human development is a fertile patch of land, a small but vital sanctuary called Kimana.

As long as the elephants stay within this conservancy, they are safe.

Pascal has returned to this small oasis.

No longer in musth, his demeanor has changed dramatically.

Pascal is a highly social being, and he's come to convene with friends, all of them males.

[ Elephant rumbles ] If they were in musth, these males would avoid one another or possibly engage in battle.

But now they're tolerant, even affectionate.

These connections run deep, some of them since childhood.

They confirm their friendship through rumbles and touch and subtle gestures.

A glance.

The flap of an ear.

The twist of a trunk.

They've even taken in a young orphan.

8-year-old Theo recently lost his mother in the drought.

By mentoring and watching over him, this bachelor group has become his family.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ They move as a group, a brotherhood 60 tons strong.

Just beyond this small fever tree forest lies land that was once wild.

It's now a tomato plantation.

With the encroachment of humans, the elephants are learning to adapt.

The elders are teaching the younger males, like Theo, how to survive in this shrinking landscape.

But for now, they rest up.

They have big plans for the night.

They wait until dark.

With their extraordinary hearing and sense of smell.

Darkness gives them the upper hand.

[ Elephant rumbling ] ♪♪ ♪♪ It's well planned and well coordinated.

But it's also risky.

♪♪ ♪♪ ♪♪ [ Dogs barking ] [ Men shouting, whistling ] [ Banging, fire crackling ] [ Elephant groans ] [ Elephant roars ] In clashes throughout Africa, elephants and humans are lost every year.

This time, no one was hurt.

Back in Amboseli, Esau's luck has finally changed.

He's found a female at the peak of estrus.

Her son naps, oblivious to the events about to unfold.

Of course, Esau's not the only male to catch her scent.

He needs to clear the stage.

[ Elephant roaring ] There are multiple males circling, hopeful.

[ Elephant roars ] As Esau approaches, he's exceptionally gentle, even as he blocks the other males.

[ Elephant rumbles ] She allows him closer.

[ Elephant rumbles ] Lifting 6 tons and finding his target takes remarkable skill.

Fending off interlopers is another challenge.

[ Elephant rumbling ] Her calf stays close.

[ Elephant rumbling ] Esau will stay with this female for the next few days, guarding her from other males.

[ Elephant roars ] The morning's events have been very instructive.

Young males practice endlessly, building the skills they'll need when they're old enough to mate.

♪♪ Juveniles from other families join in.

This young teen is testing the boundaries with a female.

♪♪ He sorely lacks Esau's decorum.

Just as Esau did at his age, this 12-year-old is taking his first steps towards independence.

In the coming years, he'll wander farther and farther from his family.

It's a dangerous time for young males when they strike out on their own.

Lack of experience and bad choices can be lethal.

Eventually, they'll find a group of bulls like Pascal's.

[ Elephant rumbling ] There's safety in the company of experienced elders.

♪♪ Mature males like Pascal provides stability and guidance, helping them adjust to life outside the family.

[ Elephant rumbling ] With decades more experience, older males know how to navigate the environment.

This is critical for a young orphan like Theo.

♪♪ Older bulls can help keep younger males calm and help regulate aggression.

Once they come into musth, they'll leave their companions to mate.

But when musth has passed, they'll return.

♪♪ ♪♪ The dry season is moving in, and Amboseli's grasslands have turned gold again.

When the pendulum of seasons swings, everyone must adapt.

This expert survivor has an advantage.

Her long roots help her reach water buried deep underground.

She has witnessed five centuries of seasonal swings.

But in recent decades, the extremes have become more pronounced.

Dry spells are lasting longer.

Now more than ever, the accumulated memories and knowledge held by the elders is crucial.

Kiba's family has remained in Amboseli.

At 4 years old, he's still very dependent.

It will be years before he starts to venture off on his own.

As the morning heats up, his family heads to the swamps.

Last night, lions brought down a cape buffalo.

The scent of a fresh kill is a magnet.

As Kibo's family heads east, the feast is directly on their path.

They are immediately agitated.

[ Elephant trumpets ] Lions or hyenas can take down a young elephant, but not when there's a protective family.

Still, this emotionally complex species has been known to be troubled by a kill.

Perhaps the carnage is disturbing.

Kibo is fascinated.

He manages to get swept up in the chaos.

The females are highly protective.

[ Elephant trumpets ] A young mother makes one final charge before the family moves on.

Kibo will be under close watch for years to come.

He still has much to learn.

[ Elephants rumbling ] ♪♪ On the southern border of the park, Esau is badly hurt.

With dust, he tries to soothe the pain.

He survived a battle with another bull, but the wound is serious.

♪♪ He's fallen out of musth, and his demeanor is now slower.

♪♪ He's headed to his bachelor range, where he'll find the comfort of companionship and familiar terrain.

♪♪ He's fighting the pain, but the gash is becoming infected.

♪♪ With a serious injury and highly coveted tusks, he's heading southward to Tanzania, a country that allows trophy hunting.

♪♪ Each time he crosses the border, his growing tusks increase his risk.

But to Esau, there are no borders.

This is where elephants have traveled for thousands of years, following the paths of their ancestors.

♪♪ Craig has chosen a different path.

He remains on the outskirts of Amboseli.

In his older, wiser years, he no longer takes the risks he did at Esau's age.

Craig is still a viable breeder, but he didn't come into musth this year due to the drought.

He lacks the physical bulk of Pascal.

It's harder to eke out a living here, but it's far less risky than raiding crops.

Their distinct choices reflect a deep intelligence and individuality.

Like us, no two elephants are exactly alike.

Craig is a rarity.

While so many tuskers have been lost to the lust for ivory and human conflict, Craig has survived for over 50 years, and he's sharing his wisdom.

These young bulls have also chosen to stay near Amboseli.

Here, they have a well-seasoned mentor, and Craig has companionship.

[ Elephant rumbling ] This wise old tusker could live into his 60s, a remarkable feat considering the threats facing these elephants.

Esau has crossed back to Kenya.

He's only 33, but already his future is fading.

His wound is severely infected.

Perhaps he's returned to find help.

Is it possible he knows that desperate measures are underway to save his life?

[ Elephant rumbling ] [ Dart gun fires ] Esau faces much more than threat from infection.

A satellite collar, evidence of a scientific study, might be his only hope of surviving trophy hunters.

These magnificent tusks are both a blessing and a curse.

When Esau awakens, his world will have shifted.

With an unfamiliar weight around his neck, Esau heads back across the invisible line.

Losing Esau would ripple far beyond a single life.

It would sever an ancient lineage that is irreplaceable.

Esau has crossed this border for decades, as have thousands of elephants.

But the rules have changed.

To survive, elephants must be able to migrate.

On the far edge of Kimana sanctuary, Pascal drinks from a stream that has served migrating elephants for millennia.

It's a favorite stopover between Amboseli and the national parks to the east.

♪♪ This very scene could have been glimpsed a thousand years ago, but not if you widen your gaze.

The stream lies on the outskirts of a town that sits directly on the elephants' migratory path.

A highway has grown from a footpath, and now vehicles hurtle across Pascal's reach to Amboseli.

Just beyond the stream, a corridor has been created for elephants like Pascal.

It funnels them across the highway and past the encroaching farms.

The corridor is just 80 meters wide, flanked by electric fences.

It's the last viable link between Amboseli and the parks to the east, absolutely crucial habitat for elephants and all wildlife.

Big Life Foundation created the fences as a buffer between humans and elephants like Pascal, with high-voltage electricity and speed bumps.

This narrow corridor is a lifeline for wildlife.

Cameras offer proof that it's working not just for elephants.

♪♪ ♪♪ This strange, severed landscape is not the world Pascal was born into 44 years ago.

♪♪ ♪♪ Pascal knows this land by heart.

Every hill, every path.

In the final blaze of the dry season, he knows the best acacia tree for shade.

He knows where to find the few small mudholes that won't dry up if the rains are late.

And now these younger males know, as well.

♪♪ The day is hot, but the rains will soon arrive.

The elephants are well aware.

They picked up its scent from miles away and caught the rumble of distant thunder through the soles of their feet.

♪♪ ♪♪ ♪♪ ♪♪ The rains have turned Amboseli green again.

Elephant families are pouring back to the park to celebrate and reunite.

♪♪ Another year has passed, and infants have turned into young boys with big bluster and tiny tusks.

Females are carrying new life.

♪♪ Craig is taking advantage of the abundance.

He'll soon turn 53.

Flanked by his comrades, this venerable male is sharing his wisdom.

♪♪ Pascal has returned to the park.

He's back in musth and is more impressive than ever.

♪♪ Amboseli is at its finest.

Green and teeming with elephant families.

But it's missing one crucial character.

♪♪ ♪♪ It's Esau, back from Tanzania.

His tusks and his collar are intact.

His wound has healed.

Each of these great tuskers is a miracle of survival and a key to the future.

Although they may not know it, their impact is profound, and it's already taking shape.

Because right now, somewhere on the plains of Amboseli, growing and learning every day are the world's next great tuskers.

[ Elephant trumpets ] ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.

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