Original subtitles

The world is full of extraordinary animals.

But how well do we really understand them?

How do they really think and feel?

To find out, a team of spy creatures is going undercover.

They not only look like part of the family,

they behave like them, too.

Armed with the latest camera technology,

they are going to travel the globe...

..to understand the true nature of the animals they meet

and reveal how intelligent they really are...

..how badly behaved they can be...

..how important friendship is to them...

..and if it's possible that they can truly love each other.

What they discover will change our perception of animals for ever.

Perhaps they are more like us than we ever believed possible.

When it comes to solving life's problems,

just how clever can animals be?

In the forest in Borneo lives one of our closest animal relatives,

the orang-utan.

These great apes share 97% of our DNA.

They're one of the most intelligent animals on Earth.

To film the behaviour of these shrewd primates

requires an exceptionally lifelike spy creature.

To be totally convincing,

Spy Orang-utan must mimic their facial expressions.

Rather than bare her teeth, she needs to appear friendly.

By sending out the right signals,

she soon draws attention.

Adult males are always interested in any new female.

But he needs some convincing that all is quite what it seems.

Spy Orang-utan pouts her mouth,

a sign she's not a threat.

As news gets around, a young male comes to investigate,

and he, too, seems unsure.

Time for some careful reflection.

He keeps a safe distance,

and finds an imaginative way to test the spy creature's reactions.

It's a somewhat unorthodox way to make new friends.

Solving problems creatively is proof of a clever mind.

Over time, as more orang-utans visit the strange new creature,

confidence grows that she's not a threat.

One youngster seems especially curious.

Young orang-utans learn

by constantly interrogating their surroundings, and everything in it.

Spy Orang-utan captures a unique view

of an intelligent young mind developing.

Curiosity satisfied, he heads back.

Among these orang-utans,

the thirst for knowledge has inspired some astonishing behaviour.

Careful to keep her baby dry,

the mother leaves the jungle to visit an old research outpost.

This is the human world,

a treasure trove for inquiring minds.

She quietly helps herself.

A bar of soap.

She carries her find in her mouth back to the forest...

..and joins a friend.

They appear to use the soap just as we would.

Around 40 years ago,

rescued orang-utans released here learned to use soap

by watching local people washing in the river.

But, remarkably, these orang-utans were born in the wild,

so the idea has spread among the wild population.

The sharing of the soap suggests how new orang-utans

may have learned the technique.

It's become a form of animal culture, passed on to the young,

something only seen among a few intelligent species.

Why they are so keen to lather up

is intriguing and not completely understood.

But then, nearby, a female does something

that might shed light on this extraordinary behaviour.

She chews a piece of bark...

..and creates a frothy lather in her mouth,

just like soap suds.

Rubbing it on her arm,

she makes the same movements as she would if washing with soap...

..but then starts to eat it.

Orang-utans are known to use medicinal leaves in similar ways.

So perhaps the bark has therapeutic qualities, too.

Maybe soap washing caught on so easily

because it mirrored their natural behaviour.

They also eat the suds, but strangely,

they seem to enjoy the taste.

It doesn't harm them in any way.

Perhaps it aids their digestion, too.

And now Spy Orang-utan gives it a try...

..much to the real one's fascination.

Intelligent curiosity is vital for orang-utan survival

in a complex jungle world.

In the cold and harsh conditions of Alaska,

animals also rely on their wits to stay alive.

Here, sea otters gather together in congregations known as rafts.

They are notoriously difficult to approach.

So Spy Sea Otter offers the best chance to infiltrate their world.

He approaches slowly...

..and soon captures some of the closest

and most intimate views possible.

Happy he's harmless,

the otter gets on with his daily routine.

Wherever he goes,

Spy Otter keeps a spying eye on him.

Sea otters spend up to 50% of their time feeding,

catching seafood delicacies such as clams and crabs.

But some shells are just too tough for their teeth to crack.

This is where their ingenuity comes in.

Stones are dredged from the seabed...

..then placed on their chests as anvils.

He can then crack even the toughest shell.

It's a brilliant solution,

but a mother with a newborn faces a problem.

How to feed with a baby on board?

Newborn otters are covered with soft, downy fur

to keep them warm and buoyant.

It takes three months to gain the waterproof adult fur

needed to dive underwater.

So, when he's wet and bedraggled,

the mother grooms his fur and blows in air to keep him dry and buoyant.

Having spruced him up into a floating fuzzball,

she confidently leaves him to bob about on his own.

She's now free to dive for food...

..leaving baby asleep

in his furry flotation suit.

When he awakes, he finds his mother has gone.

He swims to reach her,

but he's now fighting the tide.

But his mother must eat while she can.

The survival of both depends on it.

The baby may be struggling,

but here, mothers believe in tough love.

She can't miss the opportunity to feed.

No matter how vigorously her baby swims,

the current carries him away.

But his mother is smarter and more caring than she seems.

Far from being neglectful,

she's teaching her baby a vital survival lesson.

He's been born into a tough world.

These sea swells are nothing

compared with what he'll face in the future.

Intelligent animals spend a lot of time teaching their youngsters.

It's how they pass on vital skills.

Now another lesson.

In rough weather, sea otters

wrap themselves in kelp

to use as an anchor.

Sometimes, it helps to cosy up with someone else.

Spy Otter tries it out.

Clearly, this is harder than it looks.

In this harsh environment,

the otters' intelligence helps them eke out a living.

The arid forests of north-east Brazil

could hardly be more different,

but here, too, necessity is the mother of invention.

It's so dry, bearded capuchins find little in the way of fruit.

Instead, they have to make do with dried seeds and nuts.

But these nuts have incredibly hard shells.

To crack them open, they use stones as tools,

some almost as heavy as they are.

It's a cultural tradition

that's thought to be at least 700 years old.

Spy Rock stakes out their favourite nut-cracking site.

It takes both skill and intelligence to perfect the technique.

But the rewards are great...

..even if a little bitter.

Rolling the nut removes the unpleasant pith.

These techniques can take three years or more to truly master.

First, he uses smell to select the perfect nut.

Then looks for a good spot,

one where it won't roll away.

It's a frustrating business.

Success!

But it's never that easy.

The branch isn't a good choice.

He's learning the hard way

that wood is far too bouncy to work as an anvil.

There is only so much frustration any monkey can take.

Time to think this through.

At around 18 months old,

young monkeys start seriously practising using stone tools.

Spy Rock is designed to be the monkey's favourite shape and weight.

But it's far too heavy for a little one to lift.

It may capture his interest...

..but it's no use to him at all.

But could it work for someone else?

Spy Rock may be the best weight for the job,

but it takes all his strength to lift it.

This time, he's learned from his mistakes

and picks an anvil used by the more experienced monkeys.

But will it do the trick?

He's done it.

It's a significant moment.

Capuchins only survive here by being smart

and learning from trial and error.

But such intelligence is not confined to primates.

In the cloud forests of New Caledonia,

an island east of Australia,

lives one of the world's cleverest birds...

..the New Caledonian crow.

These crafty characters have many ingenious ways of finding a meal.

Spy Crow is here to film just what these super-smart birds can do.

This one has found the fruit of a candlenut tree.

It's a hard nut to crack,

and her beak is not up to the job.

Fortunately, she has an ingenious solution.

She places it in the cleft of a tree.

One with a stone directly beneath.

Spy Crow is in one of the few secret spots

where a branch of the correct height

is perfectly aligned with a rock below.

The crow takes aim with meticulous precision.

Then, bombs away!

But these are seriously tough nuts.

So around here, crows don't give up easily.

This time, she's cracked it.

But the crow's intelligence doesn't end here.

To enjoy the opportunities the forest has to offer,

it pays to be creative.

Even the rotting trunks of candlenut trees contain hidden treasures.

It just takes a bit of know-how to find them.

A fat and juicy longhorned beetle larva.

To capture the crow's ingenious hunting skills,

a Spy Grub is concealed in the rotten wood.

The crow's keen vision soon pinpoints the real larva,

but it won't be easy to reach.

However, this is a bird with a plan.

She selects a tool of the perfect length.

Under Spy Crow's watchful eye, she probes deep into the hole...

..dextrously aiming for the larva's jaws.

Its bite seals its fate.

The crow disarms the larva

by removing its powerful jaws.

The grubs are so large and nutritious,

a few a day is all she needs.

Caledonian crows acquire their knowledge

through both practice and learning from others.

The crow calls down a young family member

for some one-to-one tuition.

CROW CAWS

What makes Caledonian crows so special

is their skill at manufacturing the right tool for the job.

First, she removes the leafy end.

She holds it on her left side, a matter of personal choice.

She makes it look so easy.

Time for the juvenile to have a go.

But it doesn't quite reach.

This should do the trick.

But he's got to get the grub to bite,

and that's not so easy.

It's tantalisingly close.

The stick is a bit too long,

so he decides to shorten it.

It's now spot-on.

His newly-acquired skills pay off.

Spy Crow tests how difficult it really is.

Now, that's what's called beginner's luck!

Crows are certainly smart, but when it comes to using tools,

our nearest animal relatives are king.

In Senegal, the chimps' favourite snacks

are found in these huge termite mounds.

And they, too, use sticks to catch them.

The chimps fish out termites by getting them to bite the sticks.

Youngsters learn to make these simple tools by watching the adults.

But stealing from Mum is easier.

Better still, he's been given one to practise with.

Even at this age, they start adapting what they have...

..then graduate to selecting and modifying their own sticks.

There's quite an art to using them.

It takes a good four to five years to perfect the technique.

Termites have a painful bite,

so they need to be careful.

The chimps' mastery of sticks doesn't end here.

This is Spy Bushbaby.

He's based on an animal they naturally hunt.

Hiding in his protective log,

he's arousing great curiosity.

All seems calm,

but this young male is reaching maturity.

So when a female arrives, he's desperate to impress.

CHIMP SHRIEKS

And this bushbaby is bigger than normal.

So it could be the male's chance to make an impression.

He checks she's watching,

and begins his performance.

CHIMP SHRIEKS

For her eyes only,

an ostentatious show of bravado.

A classic case of showing off.

He checks she's still looking...

..then ups the ante.

Branches make a flamboyant weapon.

But she's seen straight through him.

It's all a bit embarrassing.

Trying to impress a female by taking on Spy Bushbaby

was somewhat ill-advised.

Females are the experts at hunting real bushbabies.

They use a well-crafted weapon -

a spear.

During the day, when their prey hide in hollow trees,

the chimps use sharpened sticks to catch them.

The best hunters continually modify their weapon

to suit the shape and depth of the hole.

The male has a less refined technique.

His spear isn't even straight.

It's a huge contrast with the considered expertise of the female.

The male favours brute force.

When the stick breaks, he even tries to scare it out.

Fortunately, the youngsters generally learn from their mother.

But the male perseveres.

And this time, he's made a bit more effort with his spear.

It's just a shame he didn't make it shorter.

There's little for a young one to learn here.

For the youngsters, just making a stick is an achievement.

Making one long and strong enough is even harder.

It's both technically complicated and hugely frustrating.

Even for the experts, there are no guarantees of success.

The bushbaby squeezes out,

and in a flash, it's gone.

CHIMP SHRIEKS

But there is one bushbaby that might just be easier to catch.

This female comes prepared...

..but uses a thicker branch to test the reaction.

She fashions a better weapon...

..but then has second thoughts.

She tickles it instead.

Spy Bushbaby lives to spy another day.

Intelligence allows animals to solve complex problems.

The inhabitants of the Amazon rainforest

have their own wealth of specialist knowledge.

This is Spy Sloth.

He's here to reveal how the animals find and use jungle remedies.

25% of our medicines were discovered in the rainforest,

but its animal inhabitants know of many more.

He soon attracts the interest of a real three-toed sloth.

Their first encounter is a very slow affair.

Spy Sloth's close-up view reveals something remarkable.

Its fur is crawling with other life.

Up to 900 moths and beetles can live on a single sloth.

They aerate his fur and prevent infections.

As well as the insects,

84 different fungi also thrive here.

Many are antibiotic or antimalarial,

and some have been shown to destroy cancer cells.

Usually, there is only one sloth per tree,

so this requires some careful negotiation.

It's not just the sloth's fur

that harbours a medical treasure trove.

So, it seems, does the tree it eats.

Cecropia is renowned by indigenous people for its curative properties.

It's used to ward off aches and pains,

treat asthma,

and is even an effective diabetes treatment.

But sloths aren't the only animals

who have discovered the rainforest's medicinal secrets.

Macaws are one of the most intelligent birds in the world,

and they, too, have extensive knowledge of jungle remedies.

They gather on these muddy cliffs for a very particular reason.

To find out why, Spy Macaw joins the flock.

Cavities mined in the cliffs reveal the reason for its attraction.

They eat clay,

a special kind, with therapeutic qualities.

When food is scarce,

macaws are forced to eat fruit and seeds containing natural poisons.

This clay provides the antidote.

It helps neutralise the toxins in their stomachs

and prevents them being absorbed.

In the muddy clay pools below,

other jungle inhabitants are also seeking remedies of their own.

These are white-lipped peccaries.

They, too, come for the health-giving mud.

Spy Peccary has a poolside view of all the comings and goings.

Like macaws, peccaries also need help with their digestion.

And there are other valuable ingredients in this special mud -

mineral supplements they can't get elsewhere.

Trips to this rainforest pharmacy

are a vital part of the peccaries' lives.

Spy Peccary's presence helps reassure the nervous visitors

that this clay lick is safe and predator-free.

Like macaws, dusky-billed parrotlets

use clay to combat toxins in their diet,

and gain mineral supplements in the process.

For male butterflies,

the salts they sip from the mud are needed for breeding.

When they mate, they pass these vital minerals to the females.

As the crowds build,

the most secretive creature of them all pays a visit.

A tapir - a distant relative of horses and rhinos.

He needs the clay to kill harmful bacteria

and balance the acids in his stomach.

Reassured by the gathering,

yet more skittish creatures arrive.

Black spider monkeys.

Spy Monkey is also filming and, like Spy Peccary,

his presence reassures the troop

that that there are no predators around.

The monkeys' diet of fruit lacks essential minerals,

including magnesium, iron, calcium and phosphorus.

But here, they get all the supplements they need.

The knowledge of the health-giving properties of the clay

is passed down the generations from mother to baby.

It's a magical scene, with so many different creatures

taking advantage of the healing power of this miraculous mud.

Perhaps one day,

rainforest medicines will lead us to more human cures.

Having taken their treatment,

the macaws return to the jungle and its boundless riches.

In North America,

the forest's bounty is much more fleeting.

So, for grey squirrels,

surviving the winter needs both brain power

and maybe even a criminal mind.

Each autumn, a squirrel buries around 10,000 nuts.

Its memory is so phenomenal,

it can retrieve up to 4,000 of them.

To achieve this feat, as winter approaches,

the area of the brain responsible for memory enlarges 15%.

The squirrels show another brainy trait - cunning.

A Spy Squirrel, bearing gifts,

is ready to record their devious behaviour.

He looks a soft touch.

But the squirrel needs to be sure.

He lashes his tail to show confidence.

Fluffing it up makes him appear bigger,

and shows who's boss.

Spy Squirrel is a pushover.

He's going to be popular.

The nut is immediately stashed away.

But clever minds can also be devious...

..and this squirrel watches where the nut is hidden.

As soon as it's buried, she makes her move.

OK if you don't get caught...

but there's big trouble if you do.

The duped squirrel needs to be craftier this time.

The crook may still be watching,

but this is what he wants.

In a shameless display of overacting,

he pretends to bury his nut.

The thief waits until the performance is over...

..then quietly sneaks in.

But there's no nut to pilfer here.

Hardly surprising.

It's stashed in his intended victim's mouth.

With the nut raider preoccupied,

he can either eat it, or bury it secretly.

But the thief hasn't abandoned her life of crime.

Spy Squirrel has a new nut,

one with a camera.

Theft is such an easy option,

around a fifth of all squirrels steal nuts,

rather than forage for them.

It's a crafty way of letting others do the hard work.

But this time, the thief has picked the wrong nut.

When the snow finally arrives,

the squirrel's phenomenal memory map comes into its own.

Their hidden stores

keep these crafty little creatures alive until spring.

In a cold, harsh winter,

deception can be a life-saver.

On the sun-drenched African savanna,

subterfuge is just as important,

but for a very different reason.

Here, a male ostrich and his mate

will raise the offspring of up to five of his other females.

They put all their eggs in one basket,

creating one huge nest.

Joining them is Spy Ostrich Chick.

For the male, it's just another member of his ever-expanding brood.

Spy Chick is in the perfect spot,

as new life hatches all around.

This spy creature receives the same devotion and protection

as the real chicks.

With a large brood to look after,

ostriches are always alert for danger.

A leopard.

All the young can do

is stick close to their father.

But the female is a master of deception.

When there's nowhere to hide,

making yourself conspicuous is the next-best option.

She launches a carefully planned and ostentatious display,

one designed to catch the leopard's attention,

luring him away from where the babies are hiding.

She pretends she's injured and helpless,

so tantalising for a predator.

The leopard can't resist following.

But he eventually realises he's been had.

There will be no easy meal today.

With the leopard lured away,

the parents can relax.

As much as you can, with 20 young in tow.

But perhaps the cleverest scam in the animal world

can be found in South Africa's Kalahari Desert.

At the heart of this deception is the drongo,

a bird that likes to hang out with meerkats.

To delve deeper into the crafty world of the drongo,

a new spy camera is needed.

Spy Termite Mound is a natural part of the landscape -

except it can move, and, of course, it has a camera.

The meerkats feel at home with this new arrival,

and continue to forage for insects.

While they eat, a meerkat is on sentry duty,

looking for danger.

Spy Termite Mound gives a little bit of extra height.

Drongos have keen eyesight, and as they can perch higher,

they often spot the danger first.

Martial eagles are a serious threat.

DRONGO CHIRPS

The drongo's alarm alerts the meerkats.

MEERKAT BARKS

They, in turn, call and run for cover.

Having their own lookout bird

helps the meerkats spend more time feeding.

But there is a price to pay.

The drongo isn't quite as selfless as he seems,

and has learned to turn this alarm to his advantage.

He becomes an expert on their habits,

learning that when an adult finds food,

it calls out to the youngsters to share.

As the food is about to be exchanged,

the drongo calls the alarm...

DRONGO CHIRPS

..but this time, it's a trick.

As the meerkats abandon their food and flee,

the drongo steals their meal.

Onto a good thing,

the drongo tries again.

DRONGO CHIRPS

But the meerkats know when they've been duped.

And this time, no-one reacts at all.

So the drongo takes it to the next level.

DRONGO CHIRPING INTENSIFIES

But even screaming the alarm in their face doesn't work.

The meerkats are smart enough to know a cheat when they hear one.

Or are they?

The drongo has another trick to pull.

DRONGO BARKS

This time, the drongo mimics the meerkats' own alarm call.

It's so accurate, the meerkats are duped again.

Drongos get over a fifth of their daily meals

by making false alarms and stealing.

When he's exhausted all his tricks,

he tries a more brazen approach.

But he's pushed his luck too far.

He must try his scams elsewhere.

The intelligence of animals is sometimes so extraordinary,

it can truly amaze.

In Borneo, the orang-utans have ventured back to the human world

and are bathing in the river.

One of the spy cameras is soon spotted...

..inadvertently filming an intimate moment

when the pair enjoy the cooling water.

The images captured show an animal with extraordinary mental capacity,

one that contemplates and considers in a way we recognise.

Then, something happens

that confirms just how similar their way of thinking is to our own.

At a jungle hut, this female finds a saw.

Despite being totally wild,

somehow she has worked out what to do with it.

Like us, orang-utans have an opposable thumb

that allows them to grasp and handle objects with precision.

Over 20 years ago, a rescue orang-utan learned how to saw

by watching people constructing the huts here.

But this is a totally different and wild orang-utan.

She seems to take pride in her work...

..even clearing away the sawdust.

She's so smart, she uses her feet as a vice to steady the branch.

Filming a wild-born and free-living orang-utan

mastering this complex task is remarkable.

But now, she's not the only orang-utan sawing.

Spy Orang-utan has joined her.

It seems to be bringing out a competitive streak.

She's becoming even more enthusiastic.

But, for a novice, sawing is tiring work.

She's lost all momentum.

Then, finally, calls it a day.

Spy Orang-utan may have machine-like stamina,

but it's the astonishing and versatile mind

of the real orang-utan that's won the day.

She's certainly earned her rest.

In the animal world, intelligence shows itself in ways that, once,

we would never have thought possible.

From the cleverness of using tools...

..to the craftiness of deception.

From problem-solving...

..to making weapons...

..or finding jungle cures...

..we're only just starting

to realise how clever animals really are.

Next time, the spy creatures look at extraordinary animal friendships

to see how similar many of them are to our own.