The animal world is full of spectacle and wonder.
But what's it like to be right in the heart of the action?
To find out, our team of spy creatures goes undercover.
They not only look like the animals they film...
..they behave like them, too.
Armed with the latest camera technology...
..they are heading across the globe.
From the heat of the Tropics...
..to the lands that lie in the north.
From the islands of the Southern Seas...
..to the snow and ice of the frozen poles.
Our spies reveal the astonishing variety of life that thrives there,
from inside their world.
On this assignment, our spy creatures join the animal families
that dwell in the hot and humid Tropics.
In the tropical zone, life is abundant,
and the dry and rainy seasons
influence animals in remarkable ways.
When the dry season comes to the mountains of Uganda,
it brings cool nights and warm days.
As the morning mist clears, a glimpse of the wonders to come.
For now, there's just one, lone baby.
His camera eye the only clue he's not as real as he seems.
GRUNTING
His aim - to join this family of mountain gorillas.
But, first, he must gain their trust.
One wrong move and it could all be over.
They are a close-knit family.
They don't take kindly to strangers.
He offers a hand of friendship.
Will they accept his introduction?
A promising start, but, somehow, he must convince everyone.
GRUNTING
She peers into his eyes to make a connection.
Gorillas learn a lot from each other this way.
But he remains inscrutable, as ever.
Now it's the baby's turn.
Gorillas are very tactile.
A touch is an invitation to get to know each other.
But is it all too good to be true?
HE SNARLS
The great silverback.
He won't be so easily impressed.
HE PANTS
Here, he's the boss.
Spy Gorilla won't be welcomed without his say-so.
HE BARKS A warning.
Everyone must stay back.
Can our spy win him over, too?
They await the silverback's decision.
HE BARKS
Until then, there's a line no-one can cross.
His arm, a barrier between them and the newcomer.
To show respect, our spy averts his gaze.
Decision made.
Spy Gorilla can stay.
Everyone can relax once more.
CONTENTED GRUNTING
In adults, chest-beating is a show of power.
For youngsters, it's an invitation to play.
But games easily get out of hand.
Oops!
His look says it all.
Best pretend it never happened.
But it's not the end for our spy.
He lives to film another day.
HE GRUNTS SOFTLY
The dry season has also come to Brazil.
The Pantanal is the world's largest tropical wetland.
But, at this time of year, it's drying out fast.
Life gathers in spectacular abundance
around the few pools of open water that remain.
As well as egrets, caiman congregate in their thousands,
some of the 10 million found across the Pantanal.
Such abundance attracts other predators.
CHIRRUPING
Meet the world's first Spy Jaguar cub.
Caiman are the jaguar's favourite prey.
BIRDSONG
But they have little to fear from a solitary cub.
Having basked in the sun, they're primed and eager to hunt.
Spy Caiman is ready and waiting.
He's now just one of the locals.
Wherever they go, he goes, too.
It's soon clear why everyone is here -
thousands of fish are trapped in the vanishing pools.
But there is little oxygen in these waters.
And, as the day warms, it holds even less.
The caiman is ready.
Catfish are coming to the surface for air.
All good things come to those who wait.
It's a feeding frenzy.
The morning feast lasts just a brief moment.
Soon, everyone can eat no more.
Only now do the capybara venture out.
THEY GRUNT AGGRESSIVELY
They're the world's largest living rodent,
and one of the most intelligent.
They welcome the dry land that's now appearing.
It's perfect for a spot of sunbathing.
But they must keep their wits about them.
JAGUAR SNARLS SOFTLY
CAPYBARA PURRS
JAGUAR PANTS
Something else now piques his interest.
JAGUAR PURRS
Jaguars kill the cubs of others.
JAGUAR SNIFFS
But curiosity overcomes aggression.
This isn't the only jaguar here.
A rival!
Jaguars are fiercely territorial.
THEY GRUNT FEROCIOUSLY
The result is a draw.
Neither willing to risk their life.
Is this the reason for the brawling?
A partner worth fighting for?
SHE SNARLS
In courtship, it seems, the female takes control.
SHE SNARLS
Having put him in his place, she turns on the charm.
A rarely-filmed moment of tranquillity
in one of the busiest wildlife spots on Earth.
Costa Rica is next to host one of the Tropics' great events.
Black vultures gather in anticipation.
This year, they have company.
A vulture that can film.
The gathering begins on the third quarter of the moon,
when the tides are at their minimum.
Olive ridley turtles.
Many travelled over 1,000 miles to get here.
They're returning to the beach where once they were born.
WAVES CRASH
When the tide is out and the surface calm,
they come ashore.
TURTLE SNORTS
Where one leads, others follow.
For those breeding for the first time,
15 years have passed since they hatched on this very beach.
Now, they compete for a place to lay eggs of their own.
This is the great turtle arribada.
20,000 may arrive in a single day.
Only so much can be seen from the air.
WAVES CRASH
As they keep coming, so do our spy creatures.
Spy Turtle is here, as our eyes on the ground.
Turtles lay above the high water mark.
So, first, our spy must climb the beach.
In water, turtles are effectively weightless.
Now, flippers meant for swimming
must haul huge bodies across the sand.
LABOURED BREATHING
Spy Turtle is soon in prime position...
..ready to film their nesting techniques.
Her flippers become scoops.
Tools to dig a nest.
Now, the moment she came for.
Each egg is carefully placed.
Up to 100 in every clutch.
She must bury them quickly.
They're what the vultures were waiting for.
Those already buried are beyond reach,
but turtles still laying must fend off thieves.
VULTURE HISSES
As things hot up, Spy Turtle needs backup.
A clutch of hidden cameras.
So far, the vultures have had little reward.
That's about to change.
There are so many turtles, every spot has been taken.
Eggs of previous visitors are batted away like ping-pong balls.
Straight into the mouths of the vultures.
They finally get their reward.
VULTURES HISS REPEATEDLY
But all is not lost.
Beneath the sand, enough eggs will survive
to produce the next generation.
As the turtles' epic undertaking ends,
they return to the sanctuary of the sea.
Around 50 days will pass before their eggs are ready to hatch.
As the turtles' eggs are left to incubate,
Zambia is in the grip of its dry season.
The vast Luangwa River is reduced to barely a trickle.
Desperate animals gather,
seeking the only available water for hundreds of miles.
Everyone is feeling the pressure.
HIPPO SNORTS
Especially the hippos.
THEY SNORT AGGRESSIVELY
The shrinking river has forced families closer together.
Rivals now live cheek by jowl.
Tensions mount.
What must it be like inside this pressure cooker?
Spy Croc is about to find out.
It could be a dangerous mission.
Hippos and crocs co-exist in an uneasy truce.
Enough to allow Spy Croc into their midst.
The reason lies just beneath the surface.
Fish are everywhere...
..attracted by the waste the hippos produce.
With plenty of fish for crocodiles to eat,
hippos have little to worry about.
But, in the middle of the pod, where the youngsters are found,
croc attacks are still a real threat.
This is a job for Spy Hippo.
To succeed, he must give off all the right signals.
HE SNORTS
This is a high-security area.
Here, the dominant bull watches over the mothers and young.
But he seems surprisingly amiable.
Even letting Spy Hippo approach a baby.
Here, the youngsters can safely play.
For now, it's just a game.
One day, they'll be fighting for the best spots in the river.
An intruder.
A male looking for females.
The resident bull must defend his position.
HE SNORTS
It's wise to get out of the way.
But Spy Hippo is right in the battle zone.
It doesn't get riskier than this.
The rival is unceremoniously dispatched.
HE GRUNTS
As tempers calm, the hippos settle down,
doing what they do best.
Sleeping, for up to 16 hours a day.
While for some, drought is a time of hardship,
carmine bee-eaters relish this time of year.
The exposed river banks provide safe nest sites.
Spy Egret is at the heart of their colony...
..poised to capture a bird's-eye view.
INCESSANT BIRDSONG
It's the avian equivalent of an apartment block.
Back in Uganda, Spy Gorilla is now one of the family.
It's an opportunity to explore their intelligence.
Fruit Cam is a replica of a local fruit, and is totally non-toxic.
Being smart means they're fascinated by anything new.
Their social nature makes them happy to share.
It's now a game of pass the parcel.
But what about this - Spy Grub?
One of our more outlandish spy cams.
SHE GRUNTS
SHE SNIFFS
Whatever her baby finds must be checked out.
Impressed?
Not so much.
But the other spies are recording something truly ground-breaking.
CONTENTED GRUNTING
They've caught our gorillas singing as they eat.
CONTENTED VOCALISATION
It's a chorus of appreciation.
The first time this phenomenon has ever been recorded
among wild mountain gorillas.
VOCALISING CONTINUES
They not only sing for their supper,
consuming 20 kilos a day is bound to have consequences.
IT BREAKS WIND REPEATEDLY
They live in a semi-permanent state of flatulence.
IT BREAKS WIND
Back in Costa Rica, two months have passed
since the great turtle arribada.
Only one, lonesome turtle is still here...
..ready to record the next great moment in their lives.
The eggs have finally hatched.
To find the sea, the hatchlings turn to face the brightest horizon.
But there's trouble ahead.
Frigatebirds have travelled far for this event.
For the hatchlings, it's a race against the odds.
The frigates are spoilt for choice.
Spy Turtle is still at the nest site.
There's always one who's left behind.
She cannot stay here.
She, too, must run the gauntlet.
But the terrain is treacherous.
Ahead, the aerial attack is relentless.
But the urge to reach the sea is overwhelming.
Now it's all down to luck.
Another is lost.
This is her new home.
It will be 15 years before she returns to this beach
to lay eggs of her own.
WAVES CRASH
BIRDSONG
In the tropics of South America, the rains have arrived,
and the Amazon Rainforest is undergoing a magical transformation.
The daily deluge causes the mighty Amazon River to burst its banks
and flood the surrounding forest.
Water levels can rise as much as 15 metres.
For the animal inhabitants, life changes completely.
To investigate, spy creatures are everywhere.
Staked out in the trees, and in the water below.
They don't have to wait long.
MONKEY CHITTERS
Capuchin monkeys are territorial.
They make their feelings clear.
MONKEY CHITTERS
But they've never seen a monkey quite like this.
MONKEY CHITTERS
Irritation turns to intrigue.
And curiosity conquers caution.
MONKEY CHITTERS
With the forest floor under water,
the monkeys must forage in the tree tops.
Conveniently, it's the season when many trees bear fruit.
A treat not just for monkeys.
Scarlet macaws come from far and wide to enjoy the harvest.
Spy Macaw is here to greet them.
SQUAWKING
Gorging on fruit helps them reach prime breeding condition.
SQUAWKING
Everywhere, love is in the air.
Even Spy Sloth seems to have gained an admirer.
As sloths rarely cross paths,
she'll take the opportunity when she can.
Her first move is to rub noses.
Followed by a mating call.
HIGH-PITCHED SCREECHING
But, this time, her calls go unanswered.
Never mind, there are plenty more eligible sloths in the forest.
Down below, a rather bizarre spy creature takes over.
A replica of the animal it has come to film.
Amazon river dolphins.
It's an otherworldly meeting.
As eyes are of little use in murky water, they've become tiny.
Other senses compensate.
Sensitive hairs on her beak react to the slightest vibration.
While sensors in her mouth detect the electric fields of prey.
The greeting is an alien sensory experience.
Courtesies over, it's down to business.
The best hunting is found among the submerged trees.
Fish are drawn to the food and shelter they provide.
To catch them, the dolphins hunt together.
One flushes the fish from hiding,
the other...reaps the reward.
It's a technique that rarely fails.
A fish supper served up among the trees
that are usually high and dry.
BIRDSONG
In Australia's tropical north, as the cool season arrives,
the continent's greatest gathering of mammals occurs.
CHIRPING
100,000 of them in all.
They are little red flying foxes.
Mothers gather together in huge nurseries among the eucalyptus.
Today, a new bat has joined them.
A way of taking a closer look at life inside their world.
But, first, Spy Bat must earn their trust.
She has been anointed with smells from the colony.
She can also mimic their friendship calls.
CHIRPING
Having passed inspection, she fits right in.
Capturing the most intimate views of a maternity roost ever seen.
Mothers and their babies are never parted.
Even when they fly, there's a baby onboard.
CHIRPING
They're caring and attentive,
washing their pups to keep them clean and fresh.
She won't miss an inch.
CHIRPING
At several weeks old, the youngsters never stay still.
Making bath time a challenge.
The mothers raise their young in wintertime,
in what should be the coolest months.
But, today, they must flap their wings just to keep cool.
INCESSANT CHIRPING
Even Spy Bat joins in.
As the climate changes, winters are becoming hotter than ever.
Heatstroke is now a common threat.
Only the cool of evening brings some relief.
As they leave, Spy Bat quietly follows.
Its wings are designed to dampen the sound of its motors.
It also has a lowlight camera, able to film at dusk.
After the extreme heat of the day,
the river is a place to cool down and rehydrate.
They have a novel technique.
They belly-flop.
Plunge-diving traps water in their fur.
Convenient for in-flight refreshment.
But all this splashing attracts attention.
Freshwater crocodiles are moving in.
All they have to do is wait.
For the crocs, it's a matter of timing.
For the bats, it's a matter of luck.
There's always one whose luck runs out.
Refreshed, the survivors head off to find nectar.
As they feed, they pollinate millions of trees.
In this way, Australia's great eucalyptus forest
depends on flying foxes for its survival.
As the year moves on, the dry season
comes to Borneo's mysterious forests.
The creatures of the forest now congregate
around the life-giving rivers.
Most are found nowhere else on Earth.
Proboscis monkeys, the most aquatic monkey of all.
GRUNTING
They live alongside another denizen of the forest.
But this one is a spy.
He's here to meet whoever visits the river.
The group is led by a dominant male,
easily distinguished by his massive nose, used to amplify his calls.
NASAL GRUNTING
So the button-nosed youngsters have some way to go.
The rest of his troop is made up of mothers and their offspring...
SCREECHING
..including young males spoiling for a fight.
SCREECHING
But there's only one who's really in charge.
NASAL GRUNTING
Real orangutans are also drawn to the plants
that thrive near the river.
Any new orangutan always creates a stir.
Best check out this one from afar.
Now for a closer look.
Perhaps wisest left alone.
There's yet one more unique animal to meet.
SNORTING
BIRDSONG
The elusive pygmy elephant.
The smallest elephant in the world.
CURIOUS SNORTING
These surprisingly gentle creatures are rarely seen.
But, in the dry season, they visit the river more often.
Here, another spy awaits.
GENTLE GROWLING
SQUAWKING
At this time of year, the river is their main source of water.
GENTLE GROWLING
It's where they drink and bathe.
Today, they won't be bathing alone.
Assuming they let Spy Elephant join them.
TRUMPETING
They are notoriously shy, so it's a sensitive moment.
But he's soon closer than ever thought possible.
TRUMPETING
It's mission accomplished.
But who can resist meeting a baby elephant?
The reception could hardly be more positive.
A magical close encounter
with one of Borneo's rarest inhabitants.
Then, as quickly as he came...
TRUMPETING
..he's gone.
But not quite.
SQUAWKING
There's a downside of being in the heart of the action.
SQUAWKING
Like all good spy creatures, he carries on filming.
TRUMPETING
But he's certainly seen better days.
BIRDSONG
As the tropical year turns full circle,
the Peruvian coast is the venue for another astonishing spectacle.
Two million Guanay cormorants nest here,
attracted by the fertile Humboldt Current that passes just offshore.
It also sustains an extraordinary tropical penguin -
the Humboldt.
The chicks' fathers have yet to return from fishing.
HONKING
They are starving.
But the waiting will soon be over.
Spy Penguin prepares to meet the returning males.
They've been catching fish for days to feed their chicks,
but the hardest part of the journey still lies ahead.
First, a few formalities.
Now, they face a trek of over a mile.
But there's a problem.
Sea lions, and not just a few.
There are 50,000 in all.
Or is it 50,001?
A spy, with cameras in both eyes.
THEY SNORT
It can even move to capture the best angle.
To feed their hungry chicks,
the penguins must take on the sea lions.
It's so easy to put a foot wrong.
GRUNTING
Somehow, they make it through.
But their problems are far from over.
The Atacama Desert hugs the coastline.
To reach their chicks, they can't avoid it.
Spy Penguin keeps them company
as they tackle the driest tropical desert in the world.
They must pace themselves, or risk overheating.
Finally, their destination is in sight.
But, now, another problem.
The two-million nesting cormorants.
Their take-off zone lies right in the path of the penguin colony.
The returning penguins are trapped.
Reaching their chicks is now impossible.
The mothers protect them any way they can.
THEY GROWL
And still they come.
The great exodus takes two hours.
WAVES CRASH
As calm returns, the valiant penguins finally make it back.
Their chicks are fed at last.
It's also time to put our spy creatures to rest.
In Uganda, the great silverback is making his bed for the night.
A moment to relax with family and friends.
For mothers, that's easier said than done.
GRUNTING
But, eventually, sleep comes to all.
Even our spy can finally stop filming.
HE BREAKS WIND
Next time - we travel to the lands north of the Tropics,
where life is governed by the changing seasons.