[cicadas chirping]
[frogs croaking]
[water sloshing]
[rousing music playing]
[buzzing]
[Cate Blanchett] A hungry hunter...
with his eyes on the prize.
[quirky music playing]
[water burbling]
[slurping]
- [frog croaks] - [water burbling]
[wings fluttering]
[slurping]
But whatever he tries, he's just not fast enough.
[croaks]
[playful music playing]
[croaks softly]
It's as if the dragonfly can see him coming in slow motion.
- [water splashing] - [croaking]
[wings fluttering]
And maybe he can.
[mysterious music playing]
Dragonflies' food is tiny and quick.
[buzzing]
But unlike the frog...
nine strikes out of ten,
he gets a meal.
Because his visual processors work five times faster than ours
and effectively slow down time.
[distorted time music playing]
[croaks]
The frog won't stop trying.
[suspenseful music playing]
[croaks]
Close...
but no cigar.
[croaks, trills]
The dragonfly isn't just keeping an eye on his slow-motion stalker.
He also has to defend his territory from rivals.
With his eyes on the skies,
he is less likely to spy someone hiding below.
[tense music playing]
[suspenseful music playing]
[suspenseful music rising]
[slurping]
[frog croaks]
The frog may not have the dragonfly's lightning moves,
but this time, he's right on cue.
[croaks, munches]
[tranquil music playing]
A sense of timing is crucial to survival throughout our webs of life.
[birds squawking]
Nature works best when it's in sync with the planet's rhythms.
- [car horn honks] - [rhino grunts]
To make the most of it, life must time its opportunities to perfection.
[howling]
Sometimes in milliseconds.
Sometimes across millennia.
[trilling]
[wildlife calling]
[birds chirping]
Late afternoon in the Kalahari.
[soft panting]
A lioness has hungry mouths to feed.
[soft growling]
Her growing cubs need fresh meat every two days.
[wildlife screeching]
[birds squawking]
[lioness grunts softly]
There's food everywhere.
[tense music playing]
But most of her targets are faster than she is.
[soft growl]
Chase them around under the blazing sun,
and she'll quickly overheat.
[soft growling]
She needs to get close enough for an ambush.
[tense music rising]
[suspenseful music playing]
Tricky in broad daylight.
Her prey are primed to spot movement.
[lioness growls]
And once her cover is blown,
she's much less of a threat.
[birds chirping]
But she's not fully committed yet.
[bird cawing]
Because she knows the tables are about to turn.
[bird cawing]
As the sun sets, the odds shift in her favor.
[owl hooting]
She's harder to spot...
[tense music playing]
...less likely to overheat.
[suspenseful music playing]
And her night vision comes into its own.
[suspenseful music rising]
A herd of buffalo.
[soft growling]
Five times her weight,
these armored giants are a dangerous target.
[owls hooting]
But if they haven't seen her, then she has the edge.
[foreboding music playing]
[buffalo bellows]
She targets a calf.
Weaker, less risky.
[suspenseful music playing]
[calf cries]
In the twilight, she makes it look effortless.
She has already cashed in on the advantage that dusk brings.
And her cubs will feast tonight.
The sun is always setting somewhere on Earth,
creating an endless beat of changing fortunes.
[wildlife calling]
But our ever-spinning planet gives us more than just day and night.
Because the sun's power isn't the only force
that holds sway over life on Earth.
The moon carves its own path through the night sky,
pulling our oceans into a watery waltz.
And sea creatures must dance to its tune.
In Northern Australia, the tide recedes.
Beneath the mangroves, a new world appears.
[seagulls hoot]
Home to a banana fiddler crab.
He lives his life in the windows between the high tides.
So he's on a tight schedule.
[jazzy music playing]
Time to feed as fast as he can...
while his female neighbors go double-time.
His banana claw might be slowing him down now,
but when the moon is right,
his time will come.
The tide turns, and it's back to his burrow.
[cicadas chirping]
The cycle repeats.
[burbling]
But as the month moves on, the moon's pull on the ocean weakens.
Each high tide covers less of the beach.
Until eventually... for a few days...
his burrow won't get covered at all.
Now he's got one of the best spots on the beach.
And another male wants in.
Bananas at the ready.
[tense music playing]
In a shoving contest,
there's not much between them.
But when it comes to the grapple...
our champ's got the upper claw.
Go find your own burrow.
But time and tide wait for no crab.
He's got to find a mate.
[squeaking]
A quick preen and he is ready to show off his winning claw.
But in which direction?
[quirky music playing]
The beach is covered in crabs.
And he's not great at sizing them up.
How about her?
He's not her type...
of crab.
Ah...
Time to claw back some dignity.
She is more like it.
But now he's got competition from all sides.
He tries to tempt her with a wave.
But they all know that trick.
What if he goes a bit higher?
[light upbeat music playing]
They do too.
Another and another.
It's turning into quite the beach party.
[fast-tempo, upbeat music playing]
How's a girl to choose?
Finally, she selects the best banana on the beach.
And only just in time.
He seals her in his burrow before the tide returns.
[tranquil music playing]
She'll release her larvae on the next full moon...
when the strongest ebb will carry them far out to sea.
[soft lapping]
A lucky few will survive.
The rest provide a pulse of food to the ocean,
connecting whole webs of life to the never-ending rhythms of the moon.
[birds clucking]
But our planet has another cycle that shapes nature's networks in a slower
but perhaps more profound way.
The precession of the seasons.
A yearly pulse that life must adapt to.
[birds chirping]
With Earth's longer time scales, the stakes get higher.
[birdsong]
Because when opportunities only come around once a year,
you've got to grab them while you can.
[water rushing]
On Norwegian tundra...
[snorts]
...an old warrior watches over the herd.
[lowing]
The females will be in season for just a few weeks.
His only chance to father next year's calves.
[soft bellows]
[soft grunts]
Other males will want to stake their claim.
[birds chirping]
So each year,
this musk ox must face a ritual tournament to retain his crown.
[growling]
A rival.
[tense music playing]
[low growl]
For the king, the gauntlet has been thrown down.
He puts up a front.
[low bellowing]
[growling]
It's an old trick to psych out his opponent.
[snarling]
[low growling]
But the challenger doesn't back down.
They walk in parallel, hoping their size will scare the other off.
Not this time.
[growls, snarls]
[both roaring]
An airbag beneath their armored horns cushions them from an impact...
[horns crack]
...as violent as a car crash.
[low growling]
The king is a veteran of many battles.
He uses the slope to make the most of his weight.
[bellowing]
[low growls]
As he tries to gouge his opponent, he loses the upper ground.
[low growls]
Not for long.
[growls, exhales forcefully]
This time, experience wins the day.
There will be more jousts to come in this annual tournament.
And only if he can win them all
will he secure his position for another year.
[wind gusting]
Now, all across the Northern Hemisphere, winter closes in.
[wolves whining]
[growls]
In this harshest of seasons,
everyone must bide their time.
[sniffing]
[ice crackling]
Resources freeze.
Temperatures plummet.
And life is held in suspended animation.
[wind howling]
The only certainty of winter is that in time, it will draw to a close.
[ice crystals crackling]
The earth's yearly journey around the sun
brings the Northern Hemisphere back into more direct sunlight.
Longer days return.
[bird squawks]
And winter yields to spring.
This is the season that life makes its own.
[birdsong]
[tranquil music playing]
[birds squawking]
All powered by the growing warmth of the sun.
Seedlings race for their place in the strengthening light...
[rousing music playing]
...each with its own strategy to get ahead.
Leaves sprout and unfurl.
Each one, a natural solar panel, harnessing the sun's energy...
drawing in carbon dioxide and converting it into food to grow.
So many plants come to life
that the planet seems to take a deep breath in.
Carbon dioxide levels dip dramatically,
helping bring balance to the atmosphere we all depend on.
The changing season triggers countless creatures to move north
as nature's networks spring back to life.
[squawking]
Billions of birds flock towards distant breeding grounds.
[cawing]
Ocean giants travel thousands of miles in search of food...
[squealing]
...while huge herds surge across the waking landscape.
[bleating]
[birds chirping]
To succeed, all of these heroic journeys must be timed to perfection,
even those of the most miniature migrators.
[ice crackling]
As the last snow melts deep in the forest,
pools appear.
[birds cawing]
In just a few weeks, they'll dry out in the heat.
By the time one creature wakes from her winter sleep...
a countdown has already begun.
This salamander needs to reach her pool and complete her breeding cycle
before the water disappears.
[cicadas chirping]
The first spring rain...
is the starting gun for the race of her life.
[rain pattering]
In salamander speed,
she's sprinting.
Her ancestors followed the same routes through the forest.
But times have changed since they first walked the Earth.
[car approaching, receding]
In a few hours, she's almost at the finish line.
The pool where her own life began.
[frogs croaking]
Now she needs to find a mate as quickly as she can.
Other salamanders have also raced to this pool.
And they may just have a trick to help them with their speed dating.
In the forest shadows, mostly blue light penetrates.
Their vision is particularly sensitive in the twilight.
And in this blue hue, their bodies begin to glow.
[contemplative music playing]
[chittering, croaking]
[cicadas chirping]
Scientists have only recently discovered this phenomenon.
Could it be that it helps in their race to find a mate?
[crickets chirping]
Now she can lay her fertilized eggs.
But time is already working against the next generation.
They need to hatch and finish developing...
before their pool disappears.
And it's already started shrinking.
[birdsong]
Every spotted salamander's life is hurried by the ticking of the seasonal clock.
So too are countless other creatures.
[chirping]
Their lives tied to the rhythms of the earth, moon, and sun.
[birdsong]
But some mysterious beings dance to their own beat,
keeping time not in seasons, but in decades.
[mysterious music playing]
Inside a maple tree, sap flows for the first time since last fall...
kick-starting new growth.
[birdsong]
But deep below ground, one creature is using this pulse
to count the passing of the seasons.
A periodical cicada.
She feeds on the tree's sweet sap.
So as it rises each spring, she can tell that another year has passed.
She burrowed underground 17 years ago.
Now she's tunneled to the surface,
ready for the moment she's been waiting for.
As darkness cloaks this Indiana woodland,
things are about to get strange.
[intriguing music playing]
Aboveground, she's vulnerable.
[squeaking]
But she's timed her emergence to perfection.
There's safety in numbers.
Billions of cicadas have synchronized their 17-year life cycle.
[skittering]
Like a zombie horde, they rise in unison.
Safely off the ground,
they begin the next stage of their resurrection.
[intriguing music playing]
An eerie transformation
into their adult form.
[cicadas chirping]
[chirping intensifies]
For the first time in 17 years,
dawn breaks to a chorus of cicadas almost as loud as a chainsaw.
[loud chirping]
The neighbors barely know what's hit them.
[loud buzzing]
The last time these insects appeared was long before they were born.
[crunching]
It would be terrifying if they weren't so tasty.
For the next few weeks, this banquet puts meat on everyone's menu.
[loud chirping]
But with more than a million in a single acre...
the diners barely make a dent in the buffet.
[loud buzzing]
So the risen can finally achieve their purpose.
They mate, and the females lay their eggs.
[dramatic music playing]
It's their final act.
Within a matter of weeks, all that's left are husks.
A massive dose of fertilizer,
pulsing life back into nature's underground networks.
[mystical music playing]
Why 17 years?
We still don't really know.
But this pattern evolved deep in the past
when a long life cycle may have helped to survive more frequent cold snaps.
Because our planet also has climatic rhythms
that span tens of thousands of years.
Far beyond any living creature's sense of timing.
[rousing music playing]
But the slowest changes can have the most profound effects on life.
[croaks]
For better and for worse.
The Sahara Desert, as large as the United States
and one of the harshest environments on Earth.
If you're not adapted to the heat, you won't survive.
[sand gusting]
This light-footed agama lizard
is small enough to find shelter.
And his scaly skin keeps much-needed moisture locked in.
[skitters]
[soft munching]
But even he needs to drink sometimes.
[suspenseful music playing]
Fortunately for him, even in this barren wilderness,
there is water.
[intriguing music playing]
A miraculous oasis for weary desert travelers.
[chirping]
But it might not be as welcoming as it seems.
[tense music playing]
[skittering]
[ominous music playing]
Incredibly, this pool is full of crocodiles...
in the middle of the desert.
A hundred miles from the nearest flowing water.
[low growling]
While their far-flung relatives swim through lush swamps,
these crocodiles are trapped here.
For them, it's not an oasis,
it's a prison...
[snarls]
...where every inmate must fight for themselves.
[skittering]
There's fierce competition for anything that moves.
A migrating honey buzzard stops to drink...
[tense music playing]
...and wades in to cool off.
[sinister music playing]
It won't feed everyone.
If they stay here, they could starve.
But if they make a break for freedom...
[flies buzzing]
[buzzing intensifies]
It's a desperate dilemma as their world shrinks around them.
But the fact they're here at all is a sign of a rhythm measured in millennia.
Because it wasn't always like this.
[intriguing music playing]
Just a few thousand years ago, this desert was green and fertile.
Crocodiles swam in flowing rivers.
Because our spinning planet has a long-term wobble
that repeats over millennia,
moving its hemispheres closer to and then further from the sun,
and altering our climate as it goes.
On its current path, the West African monsoon weakened,
and rain stopped falling in the Sahara.
Within just a few hundred years, the crocodiles' lush swamps
became one of the planet's largest deserts.
[birds chirping]
But even in today's searing climate...
there is still an echo of the long-lost past.
[thunder rumbling]
Just a few precious days of rainfall each year.
This briefest of wet seasons lets us travel back in time...
to glimpse what life was like here 10,000 years ago...
in a green Sahara.
[clucking]
[birds cawing in distance]
[croaking]
[birds cawing]
[squawking]
If the inmates can cling on, in another 10,000 years or so,
the planetary wobble will run full circle.
Water will flow again,
freeing their distant descendants to reclaim long-lost rivers.
The creeping pace of our planet's slowest rhythms
makes them almost impossible to see.
But if these rhythms are interrupted even by the smallest increment,
we can start to see things change before our eyes.
[rousing music playing]
Autumn in Oregon's Cascade Mountains.
[chirping]
[breathing intensely]
This hare is trying to stay out of trouble.
With good reason.
[hawk screeches]
Hares rarely die of old age.
A hunting goshawk will spot anything that moves.
[birdsong]
So the skittish hare freezes.
Barely even breathing.
Hidden in plain sight.
[screeches]
The hawk moves on,
and the hare can breathe a sigh of relief.
But her home is about to transform beyond recognition.
[wind howling]
If your best bet for staying alive is camouflage,
how do you cope when your world suddenly changes color?
You change too.
As the winter days shorten, she molts from brown to white.
[sniffing]
An incredible costume change.
Once again, all she has to do is freeze.
[hawk screeching]
And like magic,
she vanishes.
But now, a new threat.
Man-made climate change means that some winter days
are unseasonably warm, and snow cover can disappear overnight.
[birdsong]
Her color change is triggered not by temperature, but by day length.
And these warmer days are still short.
So now, she's desperately out of sync with her surroundings
and an easy target.
[tense music playing]
[suspenseful music playing]
[suspenseful music rising]
Time for plan B.
[whooshing]
Speed.
She's lost him.
But when you're this conspicuous, staying hidden isn't an option.
[suspenseful music continues]
[suspenseful music rising]
Next time, she may not be so lucky.
[sniffs]
Mismatched hares are more likely to be picked off.
And now they're out of step more often.
[bird screeches]
Her kind could still have a future in this changing world.
This snowshoe hare has adapted to stay brown all year round.
So his life is easier when snow is thin on the ground.
[birdsong]
The future of their species may depend on more guys like him.
[sniffs]
[hawk screeching]
[bird cawing]
Nature works best when life keeps step with the planet's many rhythms.
[intriguing music playing]
So what happens when human activity disrupts the tempo?
[distorted music playing]
[wildlife screeching]
As the world changes suddenly all around us...
can nature survive...
[growls]
...the coming storm?
[epic music playing]
[closing theme music playing]