Original subtitles

Experience a world beyond imagination

where fish can fly...

lizards walk on water,

apes master tools

and frogs disappear in plain sight.

Animals do the smartest things...

through every stage of their lives.

From leaving home...

to raising a family.

From finding food...

to making friends.

They find ingenious ways to survive

against all odds.

Welcome to The Secret Lives of Animals.

A rocky outcrop in Kenya.

Home to a troop of 130 olive baboons.

This is the top male.

He fought hard to gain his status.

But it's a demanding job

and he's getting on a bit.

A younger male senses the time is right

to challenge for his position.

The older baboon knows when he's beaten...

and retreats.

Alone, he's vulnerable to predators.

To stay safe, he must find a new role within the troop.

While his young successor enjoys the benefits of the top job...

the elder spots an opportunity to get back into the heart of the group.

Surprisingly, this infant is the key.

A yawn with his teeth covered shows he means no harm.

His plan is coming together.

The new top male is not happy with him being so close...

but the old boy knows exactly what he's doing.

The females see the top male's aggression as a threat to the youngster.

Baring their teeth

and raising their eyebrows

makes it clear they won't tolerate it.

This time, it's his turn to back down...

leaving the wise old male and baby safe.

Over time, the elder baboon develops into a kind of benevolent grandfather.

Babysitting...

and mentoring the youngsters.

He's not as strong as he once was...

but he's wise and still has plenty to offer the troop.

Growing old can be a time for new beginnings.

With age comes knowledge,

responsibility and great rewards.

The oldest desert in the world...

Africa's Namib.

Water here is hard to find.

This female desert elephant is the oldest in the herd.

It's her responsibility to keep the rest alive.

They can't survive for more than four days without a drink.

So she leads them to the only permanent water hole for ten miles.

But experience tells her something's not right.

It's contaminated.

If they drink here, they risk illness.

She must look for water elsewhere.

The longer they walk, the more dehydrated they become.

But this old elephant has a trick up her sleeve.

She has one of the best memories of any animal,

and drawing on it...

she recalls every feature of this landscape

and creates a mental map of the area

so she can take the fastest route through the desert.

Here, the bushes are green.

She knows the water must be close.

But the riverbed is dry.

The youngest in the herd are desperately thirsty.

Using the most powerful sense of smell of any land mammal,

she turns detective.

And does something truly remarkable.

She digs...

four feet down,

until she strikes...

fresh water.

It's safe to drink.

The rest of the herd follow her lead.

And there's enough to guzzle up to 40 gallons each.

Her unrivaled knowledge of this desert has saved the herd.

Growing old can be tough.

But for some, it marks a new lease of life.

A Caribbean reef.

This three-year-old female wrasse is the eldest in her shoal.

Every day, she and the other females visit this sea fan.

It's home to the only male wrasse on the reef.

His coloring gives their species its name, bluehead wrasse.

He fertilizes the eggs of every female here.

And the oldest is always at the front of the line.

But in the ocean, circumstances can change very quickly.

And the next day when the old wrasse reaches the mating ground,

the male has disappeared.

Without a male on the reef, the females can't breed.

Within minutes, the old female reacts with an extraordinary solution.

She stops producing the female hormone estrogen...

and her scales begin to change color.

She becomes more aggressive.

Her body starts to subtly alter shape.

And day by day, the difference becomes more dramatic.

After three weeks, her transformation is complete.

She has become a he.

By blocking her female hormones and producing male ones,

this brilliant old fish has changed sex.

As the new male,

he will now fertilize all the wrasse eggs spawned on this reef.

For some, reinvention in later life comes easily.

But for others, it's a long, hard slog.

A giant Galápagos tortoise.

One of the most ancient animals on Earth.

At a hundred and fifty years old,

he's entering the prime of his life.

He's still growing...

so must eat lots of highly nutritious grass.

But the dry season is fast approaching.

And the food here will soon wither and die.

With the wisdom of his years,

he knows exactly what to do.

The volcanic highlands provide rich nourishment all year round.

The problem is, they are six miles inland

and a 1,250-foot climb.

The height of the Empire State Building.

It will be an epic migration.

Albeit a very slow one.

Surprisingly, his old age is the key to his success.

His large size means he can overcome obstacles

that younger, smaller tortoises simply cannot.

After a month...

he arrives.

At the tortoise promised land.

A seasonal retreat for the oldest and biggest residents of the island.

Mountain mist guarantees nutritious food

even in the driest months.

By trekking here once a year, he'll thrive...

even as he closes in on his 200th birthday.

Getting healthier and stronger.

His old age really will be the best years of his life.

And when winter arrives,

he'll make the long, slow journey back to the coast.

The secret to eternal youth may continue to evade us...

but here on the Canadian border,

one animal has found a way to put the brakes on aging altogether.

This is a monarch butterfly caterpillar.

She gorges on the only plant she can eat.

Milkweed.

And she doesn't stop

until she's grown 2,000 times in size.

Then transforms...

into a butterfly.

But winter is coming.

It will be too cold and wet for her to survive this far north.

The freezing temperatures could last for months.

Most monarchs only live for a few weeks.

So, she does something astonishing.

She blocks the production of a hormone...

which in turn...

slows her aging.

And then flies over 2,500 miles south...

to join millions of other monarchs

in the shelter of a warmer, drier fir forest.

The butterflies huddle together.

She shuts down all but her most essential life-support systems.

When spring arrives four months later,

she takes to the skies...

and heads back north...

to find a fresh crop of milkweed.

She reactivates her hormones and begins to age normally.

Now she is ready to breed.

Her clever trick means she lives far longer than the average monarch.

The equivalent of us reaching over 500 years old.

Age is no barrier to dramatic change.

With experience, we can navigate whatever life throws at us.

With the wisdom to adapt...

later life is a time to flourish...

and take flight.

Finding a family of desert elephants digging for water

in the vast landscape of northwest Namibia is a huge challenge.

So, the team joined guide Rayne Brehem

who knows this land almost as well as the animals.

As a kid from three years old, I used to go out to the rivers,

playing in the sand and sand is in my veins now.

Just as well,

as the Namib desert sands are always on the move.

It's super windy and dusty which means the car is rocking,

the lens is covered in dust

and we're all inhaling about a kilo of dust every second.

Shifting sands mean tracking must start from scratch each day.

So, in the morning, you're looking for the most crisp lines.

At the back of the track, will always be really clear, defined

and the front of the track will have, like, a drag mark or a flick mark in front

and that'll show you the direction that they're going.

Now they know which way the elephants are heading,

the team tries to catch them.

But who is following who?

I'm getting more tracks on top of our tire tracks.

So, I think when we took this bend around, they were already on this bend,

and so we've kind of done that.

As the team drive, Rayne notices a change in the tracks.

As soon as you get close to water,

a lot of the time you can see them form a line

because they're just in a hurry.

They've made up their mind, they know where they're going.

With the elephants getting close,

the team must find them fast,

and the best way to do that...

is to put an eye in the sky.

With the elephants located,

the race is on to get in position before they dig for water.

She's digging. It's the first time we've seen it.

It's amazing.

Not only is the old elephant digging,

she's passing on her life-saving skills

to her young.

Let's get a spray. We want a spray.

That's really nice.

A combination of Rayne's expertise

and modern technology...

has revealed the secret knowledge

of some of the oldest and wisest animals in the world.