Sex, Lies and Dirty Tricks World's Sneakiest Animals

Now, what would you say if I were to tell you

that a freshwater mussel

was one of THE most devious animals on the planet?

Well, I know what you're thinking, you're thinking,

"Is that honestly the best he can do?

"Starting the programme with a mollusc, a watery snail?"

Well, let me ask you for something. The next two minutes of your life.

Because if you give them to me,

I can promise to show you something utterly remarkable.

You see, when it comes to looking after her young,

this little mussel has a big problem.

Like all mothers,

she wants to provide her precious offspring with food and protection.

But in a fast-flowing, barren river, that's an impossible challenge.

Unless she can enlist help from an unsuspecting neighbour.

Like, say, a bass.

But first of all, she's got to well and truly dupe it. Just watch this.

Hidden inside her shell is something extraordinary.

The perfect fish lure.

An incredible copy of the small fishes she lives alongside.

Which happen to be the bass' favourite prey.

It's totally tricked.

And when the bass attacks...

..the mussel fires her young straight into its face.

Because this is exactly where she wants them.

You see, her little ones snap shut on the fish's gills,

where they feed on nutrients from its blood.

Her brood are safe.

And when they're big enough, they drop down to the riverbed

and grow into adults.

She's pulled off the perfect con.

The most extraordinary thing is

that this mussel doesn't even have any eyes.

She can't even see the fish she's mimicking in minute detail

to get exactly what she wants.

This is a very sneaky solution to a childcare conundrum.

It's transformed the modest mussel into a master of deception.

And it turns out that this mussel isn't the only one

tricking other animals to start and raise a family.

All animals face the same ultimate challenge.

They've got to successfully produce the next generation.

But it's far from straightforward.

They have to win a mate...

..and then care for their young...

..to make sure they survive.

So, how do animals increase their chances in the minefield

of the mating game?

Would they lie, cheat,

even steal from one another just to get an advantage?

Come on! Of course they would.

Join me as I met seductive sneaks...

..love rats

and some very dysfunctional families.

Animals doing whatever it takes to survive.

'The first problem animals face is finding a mate.

'But this is far from straightforward.'

You see, many animals live in complex social groups,

where only certain individuals are allowed to breed.

Take these long-tailed macaques, for example.

Somewhere in this group is a dominant male, the alpha male.

And he enforces his dominance

for the right to mate with all of the females here.

SNARLING

So amongst many types of animals, when it comes to mating,

there are rules.

But, of course, we're talking about deception here,

so those rules are made to be broken.

So, how are those animals at the bottom of the pecking order

going to get what they want?

BIRDSONG

A mob of red kangaroos.

This male is a long way down in the group's hierarchy.

If he wants to have young, he's going to have to take on this guy.

The alpha male.

Only he has the right to mate with the females in this group.

Now, our young male could choose the hard way.

The honest way.

And fight his way to the top.

But it could take years to grow strong enough

to dominate his rivals.

And it's risky.

With a kick that can crush bone,

kangaroo fights can end in serious injury.

So instead, he opts for Plan B.

Cheat.

If the alpha male isn't looking...

..and it's always worth checking...

..he takes a chance.

This illicit liaison is also in the interest of the female.

By mating with other males,

she's mixing up the group's gene pool,

which could give her offspring an advantage.

The crafty pair have got scot clean away with it

and the old alpha male has absolutely no idea

that he may not have fathered the next generation.

This sneaky strategy is seen right across the world.

BIRDSONG

Take this blackback gorilla in Uganda.

The only way that he can become a father

is to try going behind the silverback's back.

In fact, research shows that 15% of mountain gorillas

aren't fathered by the dominant male at all.

So it's a successful tactic.

Despite the risk of getting caught in the act.

HOOTING

ROARING

Breaking the rules gives males low in the pecking order

a chance to continue their line.

But for most males, the biggest challenge is convincing

a female to mate with him in the first place.

And some of them have come up with incredibly calculated cons

just to get their attention.

'One of nature's greatest cheats lives here.

'The grasslands of the Maasai Mara.'

Where predator and prey...

..are locked in a battle to survive.

But remarkably, one animal has turned

this ever-present danger to his advantage.

He's the sneakiest pick-up artist on the plains.

The topi.

Africa's unlikely Lothario.

The topi are gathering for the breeding season.

But playing the mating game here...isn't easy.

Fortunately, topi are ever-alert to the danger.

With ears pricked and a knowing stare,

they warn the herd with a loud snort.

SNORT!

SNORT!

SNORT!

SNORT!

SNORT!

Once her cover's blown...

..a lioness has no chance of sneaking up unnoticed.

So it's back to the matter at hand.

And time is running out.

You see, female topi are only in season for one day of the year.

And they have a whole herd of prospective partners to choose from.

So competition between these males is intense.

Losing a fight means making do with

a position on the outskirts of the herd,

where it's much harder to attract a mate.

Fortunately, a female is passing by.

It's his big chance to impress.

But she barely notices him.

He's going to have to try something a bit more, well, underhand.

First, he scans the scene.

No sign of danger.

Which makes what he's about to do very devious indeed.

SNORT!

SNORT!

SNORT!

SNORT!

This alarm call will stop any female in her tracks

because it means that a predator must be nearby.

SNORT!

But it's a complete con.

A false alarm just to keep her close.

And by delaying a female just a little bit,

he gives himself another vital chance to mate.

And she is none the wiser.

Now, male topi who use this trick, and many of them do,

get on average three more matings with every female that they fool.

OK, it may be dishonest, but it works.

And you know the really smart bit?

They don't use these false alarm calls outside of the breeding season.

So our two-faced topi never gets caught crying wolf.

So a strategically-timed trick can keep a female close at hand.

But other ladies are far more demanding.

And to win their attention, males have to pull off

the most elaborate deceptions in the natural world.

'The outback - tough, unforgiving.

HE EXHALES

'Just like one of its female residents.

'And in an attempt to impress her,

'one male has created something truly extraordinary.'

But this designer has a devious side.

I give you the one and the only great bowerbird.

'Yes! He's one of nature's greatest architects.

'But this isn't a nest, it's a bower.

'It's built purely to impress a female.'

It's designed to entice her, to intrigue her,

to keep her around long enough to give him a chance to mate.

I think it's a fair comparison to say that this bower is

a bit like the male's internet dating profile.

It's something that he's got to tinker with,

fiddle with until he gets it exactly right.

Because it's got to work.

It's got to attract a member of the opposite sex.

But let's be honest, we all know how this game works.

Dating profiles are always improved

with a few, let's say, embellishments.

And our bird has done something similar.

He's built something sneaky into his bower.

An incredible visual trick.

Let me demonstrate.

By taking objects that we know the scale of

and playing with the perspective, we can trick the mind

and make it think that they've magically changed size.

It's an illusion we called forced perspective.

And the bowerbird's curious construction

is using just this technique.

An abandoned bower can show us how.

The design of the bower is based around this central avenue here,

which opens out on to an arena at each end.

And that's made up of small grey or white objects.

And we call it the gesso.

There are some more objects, a pile of stones right in the centre here.

The male hopes that the female will watch him

from that spot as he displays outside, on that arena.

But recently, scientists have discovered that the male has

created an extraordinary illusion.

And it's all down to the arrangement of the objects on the gesso.

Take a look. Those closest to the avenue entrance are quite small.

Those halfway across are a little larger.

And those furthest away are the biggest of all.

So let's see how this tricks a prospective mate.

She's inside the bower.

In just the position for the illusion to work.

Now, usually, the further things are away from us, the smaller they look.

But our bowerbird has reversed this with his gradient of stones.

And when the female stands in the bower...

..it changes how the world is supposed to look.

And just like us looking at the cars,

or other forced-perspective illusions...

..it takes her a while to make sense of what she's seeing.

And this makes her stay a few crucial seconds longer.

His beautiful illusion is enhanced

by the movement of objects that he tosses in front of it.

Watch this.

Come on, you have to admire the lengths he's going to

to pull his bird.

SQUAWKING

Success!

This is the first time that any animal on earth

has been seen to be using the illusion of forced perspective.

It's an illusion, it's a strategy that works.

What a bird! What...a bird!

Remarkable new science is revealing that animals across the world...

..are using mind-bending optical illusions in the mating game.

In the forests of South America...

..this male wire-tailed manakin

displays to a mate with his bright colouration.

And he's got a neat trick to maximise his assets.

Now, take a look at this.

What would you say if I told you that this strip

running across the centre of the panel was all the same colour?

You might disbelieve me because your eyes, like mine,

are probably telling you

that it's darker at this end and lighter at this.

But I can prove that we've got it wrong.

If I take the strip off and hold it down here,

you can see that it is indeed all the same colour.

And this is an example of the simultaneous brightness

contrast effect.

And the sneaky manakin is using just this illusion.

He needs to appear to be as bright, as vivid as possible.

Yet he displays in dark shadows under the rainforest canopy.

So, why on earth would he do that?

Let's imagine each of these discs

represents a male brightly-coloured bird of the same species.

I'll put the first one of these male birds on here

and then I'll put the second one displaying over here, in the shade.

And look at that.

There's absolutely no doubt at all

that the bird that's displaying in the shade looks much brighter.

And this isn't down to the way we receive things optically,

it's down to the way that our brains, and those of the birds,

register contrast.

It is a mind-blowing effect.

A shady and successful deception.

Visual trickery gives some males the edge when it comes to attraction.

But most use a far more straightforward approach.

Simply be THE biggest.

# Get up, get on up

# Get up, get on up...#

Despite all the debate, I can tell you that when it comes to

impressing the opposite sex, size really does matter.

It helps females make a choice.

Because it's an honest representation

of the male's underlying strength and fitness.

It's a foolproof plan.

Well, unless, of course, you can cheat the system.

Meet the fiddler crab.

This one enormous claw means that he's a male.

Eyeing up the beach, he's looking for a mate.

And his oversized appendage is the way to win her over.

So he takes pride in its appearance.

All he has to do is wave it in the air to attract a passing female.

The problem is...

..there's a little competition.

Look at it, it's heaving with them.

Sometimes, you can find 45 crabs in one square metre of mud.

Now, when the females are receptive,

they leave their burrows to size up the local talent.

And whilst most of the males sport an average appendage,

others are rather better endowed.

Which goes down pretty well with the females.

# Baby, here I am I'm the man on the scene

# I can give you what you want But you got to go home with me. #

And begs the question, how does the less-equipped male actually compete?

He needs to make his claw stand out in the crowd.

But how?

Well, scientists noticed that these crabs

are very particular about their neighbours.

Let me show you something.

It's a little optical illusion that might explain what's going on here.

And all I need is a small, round stone.

If we copy the stone

and surround one with larger stones

and one with smaller stones,

the stone on the left appears smaller than that on the right.

But if we switch sides...

..the other stone appears smaller.

This is a trick of visual perception

and it's known as the Ebbinghaus illusion.

If a crab could surround itself with smaller males,

then this trick might just work.

Because its claw would look larger than it really is,

just like the stone.

The question is, though,

how could an animal like a crab go about organising something like that?

Well, he can't just wander around and stand next to a smaller-clawed crab

to make his look bigger, he's got to stay near his burrow.

It's vital for his survival.

It's his bolthole at high tide.

And to escape from predators.

So instead, he does something extraordinary.

He manipulates his neighbours.

If a rival male moves into the territory next door

and it's got a small claw,

then the central crab doesn't bother to challenge it at all.

It will only challenge a new neighbour

if it arrives with a large claw.

And it doesn't stop there.

You see, he'll also defend his small-clawed neighbours

by driving out any intruder with a large claw.

All for his own gain.

Because if he can permanently surround himself

with small-clawed neighbours,

then his average claw will appear relatively much larger.

Simple and beautiful.

And I can actually see it happening right here, now, in front of me.

It's a very sneaky solution from a very crafty crustacean.

I love it when it's the little things that really get you going.

Not the tigers, the dolphins or the chimpanzees, but the crabs.

How many times have you not looked at a crab?

Just thought, "Well, it's a crab".

And yet their life histories,

their lifestyles are incredibly fascinating.

I mean, waving your claw about and making it look bigger.

It's brilliant. It's absolutely brilliant.

From artful illusions, let's move on to blatant cheats.

You see, some males will go to extreme lengths

to trick the competition and beguile the girl.

And to start the next generation,

one animal is even breaking the fundamental laws of nature.

'The Brouage wetlands are the stronghold

'of a spectacular bird of prey.

'The marsh harrier.'

In the breeding season, this male has a problem.

Competition with other males over breeding territories is intense.

SQUAWKING

But he has an extraordinary solution.

In fact, a ground-breaking discovery has completely changed

everything I thought I knew about this bird.

Take a look at this.

This is what I'd call a pretty typical adult male marsh harrier.

It's got these grey panels in its wings and this plain grey tail.

And I'd have said that was a male. I'd be pretty certain about that.

I'd have said that this one was a female.

It's a much browner bird

and it has these pale leading edges to the wings here and a pale head.

I'd have said it was a female, but I'd have been wrong.

You see, this isn't a female, it's a male in disguise.

Since he became an adult,

this male has grown feathers that make him look like a female.

It's remarkable because in many species, the harriers included,

males and females deliberately look different.

It's called sexual dimorphism.

Both sexes use these visual cues

to know how to behave towards one another.

Whether to fight, or to flirt.

So, why would this bird intentionally put on this pretence?

What's going on here really is quite extraordinary.

And scientists have been studying these birds

to see why they're doing something so extreme.

And the results they've come up with are truly remarkable.

'I'm in the middle of a male marsh harrier's territory.

'And using these models, I'm going to conduct an experiment.'

Under the strict guidance of the scientist working here,

I'm introducing an intruder into this territory

in the form of this decoy,

which has been very accurately painted

to look like a typical, traditionally-marked male marsh harrier.

'Here's the resident male.'

During the breeding season,

male marsh harriers are fiercely protective of their nesting sites.

He's spotted the decoy.

Legs down, talons out.

SQUAWKING

This is a clear threat to the intruder.

Who he sees as a rival.

'But what happens if we put out a different decoy?

'Enter the female mimic.

'How's he going to react to this one?'

Here is our male. It's drifting over the reeds now.

Here it is, here it is.

Right over the decoy.

And there's no doubt at all that he saw that decoy.

There was no aggression there at all. He just drifted past.

Pretending to be female stops these male birds from being attacked.

Using their devious disguise, they sneak past other males

and right over their turf without any conflict.

Then they set up their own territory right on the doorstep

of a typical-coloured male.

'But, of course, the ultimate goal for these males is still to breed.'

So, how does that work?

Well, when our cheat meets a real female, he switches tactics.

SQUAWKING

Just like a typical male, he courts her with an elaborate sky dance.

She has no doubts at all that he's a male bird.

'They settle down to raise the next generation.'

He gets access to prime hunting grounds

and can bring up his chicks without any conflict.

It's great, isn't it?

This uniquely sneaky strategy

means that the cross-dressing male

has a much easier time when it comes to rearing his family.

But you know the most remarkable thing of all?

It's such a successful strategy

that 40% of the male marsh harriers in this population

are now using it to their advantage.

These marsh harriers are committed to their cross-dressing colouration

for their entire lives.

But in the ocean, there is

an animal that can change its disguise in just an instant.

Giant Australian cuttlefish, up to a metre long, are gathering to breed.

The marble-coloured females

draw in their tentacles to show that they're impressed by a male.

The big guys with bold,

striped courtship patterns dominate this crowd.

They guard females underneath their bodies.

A small male has a tough time even getting a look-in.

The dominant male sees him off with an eight-legged arm-wrestle.

But this little chancer is about to pull off his party trick.

He draws in his tentacles to look like a female.

But that's not all. He even changes his pattern to complete the con.

Using this devious drag act, he slips underneath the male.

As far as the big guy's concerned, he's now protecting another female.

But beneath him, our cross-dresser is mating with his female!

And he's ensured that at least some of the next generation belong to him!

These elaborate illusions, tricks and cons

give animals an advantage when it comes to mating.

But there's a bigger challenge ahead once their little ones are born.

WAVES CRASH

To make sure their offspring survive,

animals have to provide food, shelter and protection around the clock.

It's a massive investment of time and energy.

So perhaps it's no surprise that some of them

have found very sneaky ways to reduce these childcare costs.

Introducing the emperor tamarin.

Ouch!

They're called emperor tamarins because of this extraordinary

moustache here.

Reminiscent of a Chinese emperor.

And as you can see, they're a very small monkey species,

which means they can occupy a very particular niche.

They can reach right to the end of the thinnest little twigs,

where they forage for fruits and also for insects.

But, of course, being small does also come with some disadvantages.

Particularly when it comes to having your young. Ouch!

Emperor tamarins live in the rainforests of South America.

This female, named RC because of her radio collar, is a new mum.

These tamarins are tiny.

So to make childbirth easier,

they have two smaller twins rather than one large baby.

Nevertheless, together,

these twins weigh about 50% of her own body weight.

That's a bit like me carrying a couple of...

Well, not just carrying a couple of toddlers around,

but leaping around in the branches of a tree,

carrying a couple of toddlers.

It's a real burden.

A burden on their ability to find food for themselves

and successfully rear those young.

They need some help.

And to get it, RC has been very devious indeed.

Scientists have discovered that she's at the centre

of an elaborate con.

They use coloured beads to identify the males in the group.

This one is Purple Beads.

RC mated with him five months ago.

And he's arrived to help bring up the babies.

That's good news. The childcare is now split 50/50.

But hang on. Red Beads has also reported for childcare duty.

And finally, No Beads is also taking a turn looking after the twins.

Now, with childcare covered, RC can finally forage.

Getting food for herself and to help produce milk for the twins.

The question is, how on earth has she enlisted so much help?

Well, back in the breeding season,

it turns out that RC didn't just mate with Purple Beads.

She deliberately mated with Red Beads.

And No Beads, as well.

It's created such confusion

that now, none of the males actually know who's the daddy.

But if there's any possibility that the twins are theirs,

then, of course, it makes sense to invest in looking after them.

So they all chip in with the childcare.

By playing the genetics to her advantage,

RC has elicited more than enough help.

It's an absolutely brilliant maternal monkey con.

It's magnificent.

It's hats off to the tamarin.

So two-timing tactics

are a way of shirking some parenting responsibilities.

But other cheats have managed to get out of childcare altogether.

BIRDSONG

And this plays out as one of the darkest deceptions of all.

Meet the greater honeyguide.

CHIRPING

As its name suggests, it guides people to honey-filled bees' nests.

The deal is that both sides get a reward.

So our honeyguide seems a caring, sharing kind of bird.

But when it comes to parenting, she has a sinister secret.

Because she doesn't do any at all.

And the key is conning another species.

An unsuspecting pair of little bee-eaters.

Their nest is just inside an abandoned aardvark burrow.

It's pitch-black in here, but with the help of specialist cameras,

we can reveal the extraordinary events inside this nest.

The bee-eaters incubate their precious eggs around the clock.

Each is barely the size of a fingernail.

But look closer.

The slightly larger one is the egg of our honeyguide.

Her devious plan has already been laid.

You see, honeyguides are brood parasites.

Much like another bird we're very familiar with.

The Eurasian cuckoo.

They lay their eggs in other birds' nests.

And apart from a small size difference,

they mimic them perfectly.

The parents, in this case, a pair of reed warblers,

are completely fooled, and they incubate them all.

Leaving the female cuckoo completely free of any responsibility.

Back in Africa, it's a similar story.

The doting bee-eaters care for all of the eggs.

But the honeyguide has a new problem.

Her chick needs the bee-eater's sole attention to survive.

So, how is she going to orchestrate that?

One of the eggs has hatched, and it's the honeyguide's.

Exactly as she intended.

Our honeyguide incubated her egg inside her body before laying it.

Ensuring that it hatched first.

The bee-eaters have been completely duped.

They believe this colossal chick is their helpless first-born

and they do everything they can to care for it.

Keeping it warm...

..and working tirelessly to find it food.

But as the other eggs near their hatching date...

..all of this is about to change.

Above ground, the cuckoo chick has an extremely underhand way

of dealing with the competition.

The imposter's innate response to unhatched eggs...

..is quite extraordinary.

It heaves them straight out of the nest.

Removing the problem.

And ensuring that it gets all of the food.

Until it's old enough to fledge,

no matter how...big...it gets.

But our honeyguide chick can't kick out the other eggs.

It's deep underground in a burrow.

And these eggs are now starting to hatch.

It needs another way.

And the chick's solution would make its scheming mother proud.

It's been growing a very specialised razor-sharp bill.

Now, remember, it can't even see its rivals.

But it takes a stab in the dark.

This is pure instinct at play.

One by one, each of its foster siblings is killed.

This behaviour is a shocking new discovery.

But it's also a strategy that works.

The honeyguide chick now has the bee-eater's undivided attention

until it's ready to leave the nest.

As for the adult honeyguide, well, not only has she got out

of the effort of raising a family,

she never even sees her own chick.

Surely the most devious childcare plan that's ever been hatched?

Crafty cuckooing has to be the sneakiest way

of avoiding parenting duties.

But even the most dedicated parents face a problem.

Because, often, their offspring are also trying to trick them.

You see, all young animals have their own agenda.

They want more time, more food and more attention.

More than their parents want to give.

In nature, there's always an underlying conflict between parents

and their offspring.

A form of competition.

At times, the adults don't want to feed the young

quite as much as those young would like.

But I've got to tell you that some youngsters have come up with

an extraordinary scheme to get what they want.

These bold and boisterous

black and white birds are called pied babblers.

These striking four birds here are the adults.

Hiding in the shelter of the bushes are the plainer brown youngsters.

But don't be fooled by their dowdiness.

These young chicks are out to trick their own parents.

BABBLERS SQUAWK

They already have the whole family running around after them.

Their parents and the older siblings are working relentlessly

to satisfy their appetites.

But as far as they're concerned, that's still not enough.

So, is there anything that they could possibly do that would get them

any more food?

Well, yes.

Actually, there is.

But it's pretty outrageous.

It involves the babblers' predators.

The Kalahari is a dangerous place to live.

So, for a young bird, staying hidden is by far the safest option.

And yet, this is when they do something very strange indeed.

Rather than hiding from predators,

it's almost as if they've got a death wish.

These two youngsters have hopped right out into the open.

And they're making lots of noise.

This is asking for trouble, surely,

because they're very vulnerable to any predator.

Why would they be doing that?

Well, there's a reason for everything in nature.

Surely, there's got to be some method in this madness?

There is.

A remarkable new discovery is revealing a manipulative masterplan.

Consider the scenario.

We've all seen it.

A child having a tantrum in a supermarket aisle.

What it's doing is making a scene in public

so it might just get its bag of sweets.

And that's exactly what's going on here.

These chicks are trying to extort food from their parents.

And I'm going to demonstrate exactly how they're doing it,

with the predator warning call of one of the babblers' neighbours.

I've got the alarm call of a starling.

So, I'm going to play this to these babblers

and see what their reaction is.

Obviously, if they know the alarm call,

they'll think that there's a predator present.

AGITATED BIRD CALL

Well, they didn't... They didn't need much of that, did they?

Clearly, these adults recognise that predator alarm call.

But just look at the chicks.

They're still out in the open, calling for food.

Now, to stop all of this noise attracting

the attention of predators,

the adults rush out to feed them.

They're trying to keep them quiet.

And by using this strategy,

the chicks can get fed an incredible nine times more food.

These chicks are blackmailing their parents.

It's despicable,

but wonderful.

Surely, these are the ultimate con artists?

Tricking their family from almost the moment they're born.

Parents all over the world have always suspected that they were

being blackmailed by their kids.

And, as this ground-breaking study shows, it's certainly the case.

Pied babbler, take a bow.

So, whether they're avoiding predators...

..finding food...

..or starting a family...

..we've met the devious animals that will stop at nothing...

..to get ahead in the game of life.

They really are the world's sneakiest animals.

I've been amazed, in fact, I've got to tell you I've been staggered

at the lengths they'll go to to transform their appearance,

or their behaviour.

I mean, you might have thought that only humans could be that crafty.

But, no.

Let's celebrate the illusionist, the con artist, those thieves.

The species that use spectacular deception

and incredible ingenuity to ensure their survival.

It's hats off to the natural born hustlers.