WHALE SINGS
SINGING CONTINUES
A male humpback whale singing
as he hangs in the vast blue emptiness of the ocean.
WHALE CALLS
He's proclaiming his presence to females.
WHALE SINGS
If he gets a response,
he will have solved a major problem faced by all animals
that live in the ocean.
How to find others who have to play the mating game in
the largest and least-populated habitat on Earth.
Every year, humpback whales leave their cold, rich feeding grounds
and swim nearly 3,000 miles to assemble in Hawaii.
These warm waters are a safe playground
where mothers can give birth.
Not all the females here have calves.
This one is announcing that she is here to mate.
WHALE CALLS
It's the signal that the singing male has been waiting for.
But he is not the only one who's heard it.
He has rivals.
This may be his only chance to mate this season.
The female takes the lead...
..and the males chase after her.
The more males she attracts,
the greater her choice.
There are now over 20 males chasing after her.
They race to take pole position alongside her.
Only the strongest are able to keep up.
They bellow and blow huge curtains of bubbles
to intimidate one another.
She slows down -
that forces her pursuers closer together.
And the chase explodes into violence.
The 35-tonne males barge into one another
as they try to force their way to the front.
A larger male pushes a rival aside.
Then, without warning, she calls a halt.
Fewer than half her suitors remain.
They circle her, keeping their distance.
All except one.
She allows him to caress her.
He has won the right to be her close escort,
and he makes sure that the others stay back.
Their mating game appears to be over.
These intimate scenes have never been witnessed before.
We still don't fully understand what is happening.
She may have made her final choice.
This may be just the first stage in a longer courtship.
What is certain is that the most private moments of her life
have yet to be documented.
No-one has ever seen humpback whales mating.
The world beneath the waves
is one we ourselves can visit only fleetingly.
And for us, it's still filled with mystery.
But in a few special places where we can spend time below the surface,
the secrets of the seas are, at last, being revealed.
The mating game, indeed, all life began in the ocean.
And still today, there is no place where it is more visible or
more varied than on a coral reef.
Creatures living here enjoy one of the most stable of
all marine environments...
..and one that contains a diversity of species unequalled
anywhere else on Earth.
Here, it's nearly always the breeding season for something.
The reef may look like paradise,
but its beauty hides a violent side.
One that determines the mating strategy of many reef fish.
These bumphead parrotfish, over a metre long,
are among the largest of the reef's permanent inhabitants.
Despite their size, when it comes to breeding,
bumpheads face the same problems as other, much smaller fish.
Adult females release their tiny eggs into the water
for the males to fertilise.
But many other creatures are waiting for that to happen
with arms and tentacles outstretched.
For many reef inhabitants, fish eggs are excellent food.
If the next generation of bumpheads is to survive,
the adults must get away from the reef and out into the open ocean.
The approach of a new moon provides the best conditions for doing so.
The high tide creates powerful currents that sweep out to sea -
exactly what the fish need.
Bumpheads come from all the nearby reefs and assemble together
in a super school 1,000 strong.
They head into deep water,
leaving the reef's egg-hungry creatures behind.
Now, the males develop white faces and striped flanks -
their breeding costume.
The mating rush begins, and soon, each female is surrounded by males.
As she releases her eggs, so the males eject their milt.
The strong tide now ensures that the bumpheads' fertilised eggs
are carried away from the dangers of the reef.
It seems an excellent strategy.
But it does have a flaw.
Huge schools of fish inevitably attract predators.
This solitary bull shark, however, is too late.
The spawning rush has ended.
But there are others for whom sharks present a far greater danger.
These little striped fish are convict tangs.
They, too, have gathered in huge schools to spawn -
and they, too, must get away from the reef.
But it's not just their eggs that are at risk.
They have attracted grey reef sharks.
Hundreds of them.
With hungry sharks above them and predators of all kinds
lurking in the coral, the tangs are trapped.
These convicts have an escape plan.
The first to spawn
attract the attention of the sharks.
The moment the sharks attack one spawning party,
another takes its chance.
The more tangs that join in,
the greater the confusion.
In the dazzle of flashing stripes and swirling clouds of spawn,
the sharks find it difficult to select individual victims.
The spawning tactic has worked.
The sharks go hungry, and billions of tiny fertilised eggs drift away
from the reef.
But in the open seas, there are other dangers.
A manta ray is waiting with its huge mouth open wide.
And this female is not alone.
Mantas are among the most social and intelligent of fish,
and they're very skilled at finding the floating eggs and other tiny
organisms on which they feed.
When food is scarce, they swim in small groups.
But where the currents create a really rich soup, mantas gather
in immense numbers.
Over 150 have found this particular feast.
An assembly like this one is rare, but when it happens,
the mantas produce one of the most graceful ballets
to be seen anywhere in any ocean.
Despite their numbers, there is more food here than the mantas
themselves can eat.
Only when the surviving eggs have developed into tiny fish
that can actively swim, will they make their way to the reef.
But not all of the reef's inhabitants are able to leave
in order to breed.
And those that stay here have developed some of the most
ingenious mating strategies of all.
This is one of the commonest and most familiar
of the reef's permanent inhabitants.
A clownfish.
She spends most of her time surrounded
by the writhing tentacles of a giant anemone.
She is head of a family.
And the biggest of them all.
Her family is growing fast with well-cared for young,
who are clearly thriving.
What could be more perfect?
But all is not as it seems.
As the largest in the family, she is clearly in charge.
But it wasn't always so.
Before she became head of this family, SHE was a HE.
It was the disappearance of the previous ruling female
that triggered this change of sex.
This middle sized fish is a male -
her breeding partner - but he is only biding his time, waiting
for the moment when, for one reason or another, she disappears.
Then it will be his chance to turn into a female and become
the new head of the family.
The smallest fish is a newcomer, a male, the lowest
in this line of succession.
While he remains small, he will not mate.
The dominant pair want to maintain their rule
and they constantly bully him.
This stress produces hormones in his body, which prevents him
from growing larger and upsetting the breeding hierarchy.
So long as he sits third in line, his mating game
is more of a waiting game, and it may be so for quite
a while yet.
She might rule her household for nearly 15 years.
Changing sex is not uncommon on the reef, but there are others
here who have even stranger breeding techniques.
These flamboyant creatures are nudibranchs.
Their vivid colours and elaborate patterns are certainly not ways
of attracting the attention of the opposite sex,
for nudibranchs are in fact blind.
Their colours instead are warnings to predators that their bodies
are packed with poison.
So stay away.
Since appearance is no help in bringing individuals together,
they have to rely on scent or taste which, under water,
is more or less the same thing.
And they play a special version of the mating game.
Nudibranchs are neither male nor female.
They're both at the same time.
So when they do find a partner, they neither fight nor flirt.
They simply, peacefully and more or less simultaneously
fertilise one another.
If only it was always so straightforward.
This is a flatworm.
Flatworms, like nudibranchs, are also both male and female and blind,
finding their way by smell.
But that is where the similarity ends.
This one called the Persian carpet flatworm because of the elaborate
patterning, is a voracious predator.
And when it comes to mating, it's also somewhat aggressive.
It has sensed the presence of another flatworm,
a potential partner.
To start with, they seem wary of one another,
and with good reason.
Each of them is trying to avoid the labour of looking
after the fertilised eggs.
It's better not to become pregnant.
Rearing up, each reveals its two-pronged penis.
And now they fence.
Each tries to stab and inseminate the other
without being stabbed first.
A strike anywhere on the body will fertilise.
A successful strike and sperm is injected into the rival.
The duel is over.
The impregnated flatworm is left with the scar and the labour
of laying the eggs.
Its only solace - it's young will carry the genes
of a master swordsman.
Coral reefs are more than just hothouses for trying new versions
of the mating game.
They're also excellent places for meeting others of your own kind.
The mantas are back.
They're well fed and preparing to breed.
These giant fish do not produce spawn.
They breed in a more complex way.
A fish is more likely to meet others of its own kind here, than wandering
around in the open ocean.
And while they wait for someone interesting to turn up, cleaner fish
give them a going over, removing any parasites or bits of dead skin.
They're quite choosy.
Only a partner with the right abilities will do.
Young mantas - not yet mature - flirt with the others.
The adults mate belly to belly.
Getting into the right position requires practice and coordination.
They don't necessarily get it right first time.
An adult female arrives and she is seeking a mate.
Any interested male must now get down to business.
Rehearsal time is over.
Several males fancy their chances.
She starts to twist and turn, while they follow.
She's assessing their stamina.
The courting males imitate her every move.
This performance may go on for hours.
Some males eventually start to tire.
And now, she ups the tempo.
Once she's made her choice, she slows down...
..and they mate.
The genes that gave them both such speed and agility are now
passed to the next generation.
After mating, the male mantas play no further role
in caring for their young.
It's a strategy common to many ocean creatures.
But not all.
The coastal lagoons of Portugal.
Here live fish that form long-term partnerships.
The seahorse.
This is a female, and she's looking for a partner.
The choice is an important one,
for the partnership is likely to last for years.
Could he be the one?
He's turned pale -
a sign that he's interested.
But she needs time to get to know him.
Once she's certain,
she, too, changes her colour to match his.
Over the next few days, they barely leave each other's side,
imitating one another's every move.
Their synchronised swimming skills will determine the success
or failure of the next stage in their partnership.
Her belly is now swollen with eggs ready to be fertilised.
On his belly, he has a pouch.
For, in seahorse partnerships,
parental responsibilities have been exchanged.
So, now she's going to pass her precious eggs to him.
The crucial act, the transfer,
is about to happen.
They position themselves with great precision,
and she transfers all her eggs without losing a single one.
The pouch on his belly now contains about 300 eggs.
It's now up to him to look after them.
And she is free to start producing the next batch of eggs.
Three weeks later,
and his pregnancy is almost at an end.
His body starts contractions that slowly increase in intensity.
And then...
..release.
Many fish give birth to live young,
but seahorses are the only group in which it is the males who do so.
The young are just ten millimetres long,
fully formed and ready to make their own way in life.
Each a perfect miniature of its parents.
This male's pregnancy has given him a guarantee of their paternity.
And, by producing live young,
he has given them an excellent chance of survival.
Nowhere is the mating game more hectic than
at the margins of the sea,
where water disappears twice a day...
..and reveals mud.
Here in the mangroves, fiddler crabs start the action just
as soon as the water disappears.
There's no time to lose.
A male - his burrow could make an excellent family home.
All he has to do is find a willing female.
And he must do so before the water returns.
His large yellow claw weighs as much as all the rest of his body,
and is completely useless for feeding.
But its colour does catch a female's eye.
And, if she needs more convincing,
the wave should do the trick.
The tide turns, the clock is ticking.
He needs to up his game.
She seems distracted.
Competition has arrived.
Lots of it.
All with the same desire.
And all with moves just like his.
Every time he waves...
..so do all his rivals.
She is spoilt for choice.
His time has almost run out.
At last, she makes her choice.
But it's not in his favour.
He'll have to wait until the next tide,
and then, try again.
Many ocean animals only play the mating game once a year.
So, for them, the stakes are particularly high.
To win, a player must be prepared to risk everything.
A colony of South American sea lions in Argentina.
Every summer, for a few weeks, they gather on the shore.
Heavily-pregnant females close to giving birth arrive
in search of a place to do so.
Any.
These safe places give the mothers
time to bond with their newborn young.
But such prime real estate does not come rent-free.
A beach master.
Over 300 kilos of muscle.
The females have landed on the territory that he had to
fight hard to establish.
Now, a week after giving birth,
they're ready to mate again.
And he aims to be the one to father their next pups.
The trouble is, he's surrounded by other males.
They all want females - and, just like him,
they all fought to establish a territory.
And.
Squabbles are common...
..but, as long as each male stays in his own patch,
they won't come to blows.
But a crowd of fertile females inevitably attracts attention.
A younger, smaller bachelor is on the lookout
for just such an opportunity.
On his own, he's no match for a battle hardened beach master.
But he's not on his own.
Other bachelors are watching.
Each would like to steal a female from the beach master.
But none of them wants to make the first move.
SEAL BARKS
Edging closer, they test the beach master's defences.
One breaks ranks...
..and then they all invade his territory.
As he tries to retain his panicking females and fight the intruders,
the raid spills over into neighbouring territories.
GROWLING AND BARKING
GROWLING AND BARKING CONTINUES
Now, the bachelors get their chance.
Using others as cover, a bachelor grabs an unguarded female.
Another targets one of the beach master's partners.
He charges to her rescue.
One on one, the beach master has the strength to stop any kidnap.
The raid is short lived, but the beach master
will have to face many more before the breeding season is over.
Each battle will sap his strength and so shorten his reign.
But bachelors who fail are even worse off.
Only those with the size and strength to defend the territory
and the females within it will win this mating game.
His dominance may last for only a few years, but during that time
he will father dozens of pups.
Among them, the next generation of males.
Including those with the genes that gave him the strength to become
a beach master.
For all those who play this mating game
there is only one measure of success.
A healthy newborn whale calf is living proof that both his father
and mother had game plans that worked.
Many aspects of those strategies remain a mystery.
One thing, however, is clear.
The success of any species anywhere depends on the skill
with which its members manage to play the mating game.
WHALE CALLS
CALLING CONTINUES
The humpback singers are just amazing.
Just being next to one whale underwater is incredible,
but then add the sound of those things.
WHALE CALLS
It just inhabits every pore of your body, every nerve cell
in your brain. You just...
Everything feels like sensory overload.
There's just a weirdly difficult to describe feeling associated
with being so close to something that's, you know,
500 times your own weight.
It's an incredibly exhilarating, demanding, exciting place to be.
Filming a singing whale was the first of many challenges
the mating game crew had ahead of them.
Cinematographer Doug Anderson and team are attempting to film
the spectacular mating contest of humpback whales.
It's known as a heat run.
100%, yeah. All right, you're good to go in the water.
No-one really knows what happens on these courtship chases,
and the crew hope to be the first people ever
to document humpbacks mating.
This thing is such an overt, massive piece of behaviour.
What the detail?
What's the details of this?
What other behaviours are happening in there? Is there mating?
Can we follow this chase to its conclusion?
That was the bit that's exciting.
From a photographer's point of view,
we're going there with a bunch of new kit to just find out
what happens and to do that
we had to make a fancy pole cam.
Doug's fancy pole cam is a stabilised camera fixed to the side
of the boat.
Do you want to just run on that?
The plan is to position the boat alongside the whales
during their courtship chase and use the camera to try and understand
what the whales are doing.
The team is working with experienced scientists
who want to use this technology to learn more about whale behaviour.
We had to get close and even though they are massive animals,
they have an incredible ability just to swerve and miss
and create space.
And we became a part of it.
Whales coming in at 12 o'clock.
All right.
Well, this is against...
OK, let's get ready to go around to the right.
Three, two, one, go.
Go, go, go.
Got it. OK.
They just went underneath the bow. Going right or left?
What speed are we going?
The noise of the whales hitting each other on the surface,
it's like, it's palpable.
The crunching of these bodies coming together, it's visceral and violent.
You could see individual whales and their strategies and whales
bottling out and peeling away.
On the left.
It just felt like such a privileged view being allowed to be closer
and in a more intimate position with this massive event
than any film-maker ever has.
It was incredible to see these extended shots of whales
bashing into each other, competing for space and everything else.
But we weren't seeing anything new.
The pole cam provided an unparalleled view of one
of the greatest battles in nature.
But it didn't get the team any closer to revealing
how a heat run ends.
After following the chase for hours,
the whales come to a halt and Doug takes the chance to get in the water
right where the whales have stopped.
We'll just try and get down on the edge of it.
Like, to whatever depth it is.
What he then witnessed was truly remarkable.
We got in and she was just there hanging in the water.
I think what was going through my head was, "If not now,
"then when will I regret not just trying to become a part
"of this scene?"
I mean, adrenaline was high and excitement was through the roof.
These animals are so large, and I had never even heard
of anything like this.
WHALES CALLING
In the moment, I felt like I had an invitation to become
as much a part of the scene as I could.
I thought this is mating.
He's won.
I'm as close to mating as anyone has ever got.
And the male came over her back and drew his chin so delicately
over her back, almost like a caress across the top of her head.
It was just such a tender moment between such enormous animals.
The male beat his tail towards me.
I didn't even find myself flinching.
It was just a part of the moving of.
And I was left bewildered.
I thought I was going to see something that was an end to this.
But actually all I saw was another bit, another chink through a window
into what the heat run is.
We have to go now, but... Because it's going to be dark.
But I'm guessing that I don't know, that's it, that's the point.
If I could have stayed there that night,
and filmed in the dark, you know, or under moonlight or, you know,
if we had the ability to do that, then it's in that space that we find
the next piece of the puzzle of what this is for all
of its bluster is the prequel to the main event.
And we have just picked up the first tiny piece in the puzzle
of what that is.
And that is great.
But I would love to see the rest of it.
WHALES CALLING
Next time...
When animals that live in rainforests want to mate,
their challenge is finding a way to stand out from the crowd.
Some are spectacular show-offs.
Others must fight.
But sometimes working together is the key to success in jungles.