Original subtitles

Killer whales are one of the most

successful predators

on the planet...

..but one tiny group in Antarctica

have the most spectacular

hunting technique of all.

Swimming in tight formation,

they create waves so powerful

and accurate, they can wash a seal

off a piece of floating ice.

Watched by millions in Frozen Planet II....

..it's earned them a fearsome reputation.

But they are not just ruthless killers.

They live in close families,

with complex lives

we know little about.

Now, a hand-picked team of scientists and film-makers

are heading to the Antarctic Peninsula

to unlock secrets in the lives

of these whales.

- We're about to catch our first glimpse of Antarctica

and possibly the killer whales.

- We really want to witness the power of the waves,

the sound of them crashing.

It is utterly spectacular.

- Antarctica's changing rapidly,

and so it's paramount that we learn as much as we can about them

before we reach some sort of tipping point.

- But with only a few weeks of good weather to complete their work,

the pressure is on.

The team is heading deep into

the Antarctic, to an area where

whale biologist Leigh has studied these

killer whales before.

- In this part of Antarctica,

the population is only around 100 animals,

and that's been declining at approximately 5% per year.

So coming down here,

learning more about them

and then, ultimately, how they

conduct their lives in this environment,

that's what we want to understand.

- But with a search area of 50,000 square miles...

..the team has to stay on constant watch.

- The critical element

is spending time at the top of the boat, as high as we can be,

binoculars glued to our eyes.

- This is such a shifting landscape

and everything is moving all the time.

The killer whales, the boat, the ice.

It's like looking for a needle

in a wet and very moving haystack.

- We have these small windows of opportunity

to try and unlock all these secrets,

so any little bit of data we get is so, so valuable. So..

..I'd better stop talking and start searching.

- Trying to find a black-and-white killer whale

in a black-and-white landscape is tricky.

- These killer whales are easily capable

of covering over 100 miles a day.

We're doing between 50 and 100 miles a day,

but whether we're doing it in the right direction,

that, we'll have to wait and see.

OK, there's a group up.

- Oh, yes.

So you see the triangular-shaped island bit in the middle of that,

straight down from it? That's where they just blew some air.

First time ever seeing killer whales,

so we're off to a pretty magical start.

- Everything we could have hoped for on day one,

with such a short window to work in.

And hopefully, they're animals that I know,

that it's kind of like finding old friends again.

- The team heads out to meet them.

- Everything we're filming together is a lot to do with teamwork

and communication, just like the killer whales themselves.

Tom's giving very clear, calm instructions.

Dave's navigating the ice like an absolute champ.

And I'm holding a big piece of metal and trying very hard

not to dunk the extremely expensive camera in the water.

- We need to go out in the Zodiac.

Are you happy to shoot photo ID? - Yep.

- OK, so let's head this way, Dave, so we give them some space.

- They are absolutely enormous.

You can't really appreciate the scale of them

until they're next to a six-metre Zodiac.

- Pack ice killer whales can grow to

almost eight metres in length.

- See him?

- Oh! Wow!

It's Kinzel.

- This is a whale Leigh knows well.

- This killer whale is named Kinzel

because he's got a very distinct sort of K shape

to the trailing edge of his dorsal fin.

- Kinzel is a young teenager,

and he's with his little sister,

six-year-old Georgie.

But the most critical member of the family is missing.

Their mother, Gertie.

- I've never seen Kinzel without Gertie.

They're mother and son, so they're always together,

or should always be together.

- In seven trips to the Antarctic,

Leigh has developed a deep bond with Gertie.

- Our core reason for being here is to find any pack ice killer whales,

but of course, you end up with favourites,

and one of my favourites, I call her Gertie.

She's named after my gran

because my gran had ten children,

so she was definitely a matriarch, an incredibly strong female,

and that's exactly who Gertie is as well.

- Gertie is the most accomplished

pack ice killer whale

Leigh has ever studied.

- She's taught me everything I know about pack ice killer whales.

Gertie has really honed her hunting technique,

so she's one of the most successful

at feeding her family.

For me, Gertie is just the boss.

- And with such a strong connection,

Leigh can easily recognise her.

- Clearly, she's had a challenging life.

You can see that in her dorsal fin shape,

and that's got two really large

notches on the leading edge.

And then she's got a small knit,

a piece taken out of the trailing

edge of her dorsal fin as well.

- An experienced matriarch,

her parenting is critical

to both Kinzel and Georgie.

Like killer whale families all across the world,

sons, daughters and grandchildren

stay with their mother their entire lives,

relying on her knowledge of where to find and how to catch food.

Females go through the menopause.

They stop having offspring in their 40s,

but can live to over 100 years old.

Survival beyond child-bearing years

is rare in mammals,

but it allows these matriarchs to devote the rest of their long lives

to passing on their knowledge

and experience.

Without them, their families

could die out.

For Leigh, studying the matriarch

is the best way to understanding killer whale behaviour,

and he learns more from Gertie than any other.

- So are you a bit worried

that you can't see Gertie, then?

- I am, because if we have a matriarch die,

then you normally see the pod collapse completely.

- Finding Gertie is now Leigh's top priority.

Also on this expedition

is marine biologist Jess.

She's here to investigate the health of the killer whales

and the world they live in.

- We're just trying to get a 360-degree view,

so that we can understand what they need to thrive.

- But to do this, she'll have to get her hands dirty.

- What I'm doing is looking for poo.

There's all sorts of information you can get from poop.

It's really like having the food chain just laid out in front of you.

People think you're going to do marine biology,

and you're going to walk around on a beach with a camera and a bikini.

No.

You're going to be massaging turds with your hands!

- But finding a poo, or scat,

floating in the Southern Ocean

is easier said than done.

If Jess succeeds, she'll be the first person ever

to collect a scat sample from a pack ice killer whale.

But even with 24 hours of daylight...

..there have been no more sightings

since the team found Kinzel and Georgie.

- It is, believe it or not, actually night-time.

I can't remember how late it is, something like 10pm or 11pm,

but it's still very light,

Antarctic summer.

- They keep looking...

..but over the next few days, they face a new challenge.

A lack of pack ice.

Pack ice is the name given to the pieces of ice that form

as the frozen Southern Ocean breaks up after winter.

These floating platforms provide the perfect place for seals to haul out.

And a resting seal is the ideal target

for hungry, wave-washing

pack ice killer whales.

But in 2023,

Antarctica's sea ice reached its lowest level since records began.

- We're now travelling through open water,

not through pack ice.

It's broken up and disintegrated to nothing.

That's a huge concern for the killer whales,

and particularly, for example, for Gertie's family.

I've seen her here every year.

This really is her patch, her core foraging zone, at this time of year.

And now, what should be pack ice is open water.

- Since 1979, there are about

100 less days of sea ice cover.

That's an impressive amount of ice that is no longer in this system.

- Now is the time when they should be feasting on seals

that would be out on pack ice.

If they're not here,

finding good amounts of food,

..then they're having to travel further between meals.

If Gertie starts to lose body condition,

Kinzel, that huge son of hers that we saw,

their health is going to suffer as well.

- There's a number of Weddell seals on the beach up there.

- With no pack ice to haul out on,

Weddell seals - the killer whales' favourite prey -

are resting on a nearby beach.

If Jess can collect their scat,

she can see if man-made pollutants have found their way

into Antarctica's food chain.

- If the killer whales are eating the seals,

it's kind of important to know what the seals are eating

because you just need to know how everything's connected.

Hi, guys.

Can we come by?

- Weddell seals can grow

over three metres in length

and weigh more than half a ton.

- Weds are a very large seal.

They have a high fat content.

It's a lot of bang for your buck.

In my opinion, this is the world's super seal, right here.

They're not land animals. This isn't what they do.

Where they excel and where they're amazing is out there,

and it's underwater, and we don't see that.

I mean, the fact that they can capture fish in complete darkness.

- Weddell seals dive as deep as

600 metres, and for as long as

80 minutes, on a single breath.

- Hello!

It's brilliant that we can come ashore and get these poo samples,

but the thing of finding this many Weddell seals on the land

is they're not out there on the pack ice.

And if they're not out there on the pack ice,

they're not food for the killer whales.

- Oh, yeah.

I didn't even like changing diapers,

but this, with the promise of

scientific discovery, I can do.

If you're looking at the health of a particular predator,

this is just a really simple way to do it.

- Science gold. - Science gold

will be the killer whale turd.

This is like science silver.

OK, I think that's probably sufficient.

He's a good assistant. He carries all the turds!

- Leigh thinks Gertie will have headed further south...

..where it should be colder, with a higher chance of finding pack ice,

so the team does the same.

Across the world, killer whales have relied on

stable conditions to develop

specialist techniques to target prey.

In the North Atlantic, they hunt herring, herding them into schools,

then stunning them

with a flick of their tail.

Others target fur seals,

striking from below, to hit them

up to 20 metres into the air.

And some hunt in groups, to tackle

prey many times their own size.

But being such specialists

means they may struggle to adapt

to any rapid changes in their environment.

If Antarctica loses more pack ice,

it will have disastrous consequences for these killer whales.

After days of searching,

the boat hits ice.

- It's so nice to see this much pack ice...

..finally, on the search.

- Ah, they're out here somewhere.

- It's constant effort to find them in this environment.

Even when you have two Zodiacs

in the water and a drone in the air,

all it takes is them feeding behind an iceberg...

..and you drive by and you never know.

- In the whale country.

- Oh, my gosh! There they are.

- Pack ice killers.

- Do you know which group this is?

- It might be Marge and Tickle.

- Leigh can recognise

many of the pack ice killer whales

by the shape of their dorsal fin and the marks on their backs.

- Oh, there's a seal. There's a seal here, right here.

- It's a leopard seal. - Dave, Dave, from Leigh.

- Go for Dave. - Killer whales are up at our 11 o'clock.

- Yeah, copy.

OK, they're spy-hopping all around the leopard seal now.

- Killer whales beat their tails

to lift themselves up to

three metres out of the water,

a behaviour known as spy-hopping.

- These leopard seals can be aggressive

and they are certainly intimidating.

They eat crabeaters, elephant seals,

fur seal pups like candy, like chicken nuggets.

- Far more aggressive than the Weddell seal,

the leopard seal sits just below killer whales

as Antarctica's top predator.

They grow more than 3.5 metres long

and weigh nearly 500 kilos.

Agile enough to twist like a snake,

and with a wide gape of

razor-sharp teeth,

they are dangerous.

A killer whale will rarely risk

hunting a leopard seal.

As Marge continues to spy-hop,

the leopard seal begins to climb.

- So the leopard seal has now managed to get to high ground.

It doesn't look comfortable.

I mean, I wouldn't be, but it doesn't look comfortable.

- But with only her young calf to help,

Marge won't risk taking on the leopard seal.

- OK, there is... Yes, there's now four whales approaching.

- Out of nowhere, reinforcements arrive...

- Now you're well and truly surrounded by pack ice killer whales, everyone.

- ..and get straight to wave-washing.

The killer whales' first wave

is designed to reduce

the size of the ice...

- It's broken the piece almost in half.

- ..which will increase the impact

of the waves to follow.

But the leopard seal

has a countermove.

- The leopard seal's now hiding in this channel

that's been left in the ice.

- The killer whales stop to assess the situation.

- They seem to be having a discussion.

- I mean, from what I can see,

I think there might be some more waves coming.

- In an incredible display of coordination,

they approach from a different angle.

Swimming on their sides,

the whales drive as much

water upwards as possible.

The faster and closer to the surface they swim...

..the taller the wave.

- So they're increasing the amplitude

and the power in each of the waves

to really flush the leopard seal out.

- This is going to be amazing.

- With a synchronised

flick of their tails...

..they aim the full force of

their wave directly at the seal.

But the seal has the strength to hold on.

An hour and a half in,

the whales continue to spy-hop

to plan their next move.

- I can almost sense their frustration.

Only a handful of people on this planet

have actually seen wave-washing first-hand.

I mean, I've been coming to Antarctica since 2009.

That's the first time I've seen that behaviour.

- The leopard seals are really agile,

so it's able to...

..jump straight back out onto the ice,

something that a Weddell seal wouldn't be able to do.

That means for the killer whales, they have to make lots more waves

because what they need is the seal in the water, in order to catch it.

- This is a battle between

Antarctica's top two predators.

For two hours, the whales send

wave after wave at the seal.

- He's still up there,

but fighting to stay on.

When you think about the amount of energy

that is expended to catch one seal...

- Eventually...

..the exhausted leopard seal...

..can fight no more.

The killer whales deliver one precision bite

to its powerful swim muscles.

- Man, they've earned this seal.

- What a team effort!

There isn't a me, me, me culture.

They're sharing this leopard seal

between all the group members,

so that everyone benefits.

- The hunt may be successful,

but it's been costly.

18 waves for just one leopard seal.

Most Weddell seal hunts

take just four.

And with each whale needing to eat

an average of a seal a day...

..they can't afford to expend

this much energy on every hunt.

- Now, they've completely vanished.

You wouldn't know there was any killer whales

here if you turned up now.

You wouldn't know that one of the world's most intelligent

animal behaviours had just occurred right there.

- Leigh and Jess want to review

Sam's drone footage to see if

the aerial view reveals anything new

about the killer whales' hunting behaviour.

- That's cool, to see how much they pump their tail

to get up and out to spy-hop.

- I think it's crazy how they, like...

The other whales just came on the scene

and it's not like they checked it out first,

they just immediately started swimming towards it.

So that makes you think that that female actually communicated

there's a seal and it's on

this iceberg, swim that way. - Yeah,

because the mum and the calf were there for a long time together,

just the two of them.

She had to have made a call,

because those other animals have come in

from afar and immediately made the wave with her.

- The camera team has captured

something never filmed before.

Not only must Marge have called for help,

but she also seemed to instruct the new arrivals

on precisely where to go and what to do.

- Tom, Sam and Helen are giving

new insight into the behaviour.

- Now, Leigh wants to investigate

how pack ice killer whales

communicate during their hunts.

But their plans may have to wait,

as a storm is fast approaching.

- It's going to blow, right? We're going to have some wind coming?

- Yeah, coming from this afternoon. - OK.

- We've got gusts at 80 knots,

so there's no way that we're going anywhere today.

I'm just double-checking that all the kit is secure

and then I'm going to go inside,

and I think I'm going to stay inside until this stops.

- Whoa!

- So the window of opportunity we have

is only a number of weeks long.

We can't really afford a lost day,

so I'm hoping this weather will break and we can start tomorrow.

But at the moment, the forecast looks like we're due to have

this weather for another day, or possibly more.

- There's still a lot we haven't done yet.

Still a lot to do. Still a lot we haven't found.

We just really need whales.

- The team loses days to the storm...

..but can eventually continue their search.

- It's a relief to even be up here looking,

to be honest, at the moment.

- We can't see any killer whales from our vantage point at the moment.

- I've got a drone view of the whole bay

and I can't see a single killer whale.

- Just beyond that iceberg, there.

- OK, they're up ahead of us.

They've come out and they're moving along the ice edge.

It would be good to try and get out and make a recording of them.

- Leigh and Jess head out.

This time, Leigh is bringing a hydrophone -

a microphone, capable of picking up underwater sounds -

so he can listen to their communication.

- Killer whales around the world use

sounds in a lot of their behaviour,

and pack ice killer whales may be very similar.

We just don't know.

So anything that we can collect here is incredibly valuable.

- If successful, he will be the first

to record their acoustics.

- I think there's about five around here.

One just spy-hopped at 11 o'clock.

- Oh, that might be Gertie.

Try and get photos. Animal on the left.

I know her. That's Jenny and her offspring, Clicker.

- Every encounter with a matriarch

provides valuable data.

- The more data we collect, the more we understand.

The more we understand,

the more we can take those conservation steps in the future.

- Right here, look.

That is a big whale.

- So every time we are able to find a group and see who's there,

we're getting a lot of information

that is feeding in to our understanding of this population

as a whole, and that's really critical.

Look at the calf, coming to say hello.

- Jenny and Clicker aren't alone.

They are in a large group, with a lot of calves.

- I can see one, two, three.

- At the moment, we've got this group

that are not out as mindless killers.

They're there socialising.

- Socialising is an essential element

in the lives of pack ice killer whales.

- These animals are not just hunters.

They're complex social animals,

with tight family units

and even tighter family bonds.

- Leigh listens to the whales as they interact with each other.

- Can you hear them?

I can hear them.

So many pulse calls and whistles.

It's so aethereal. It's so otherworldly.

The pulse calls are predominantly used

when the animals are socialising.

And whistles, typically, can be used

where the family group are establishing

and renewing their bonds between one another,

particularly, for example,

between a mum and her offspring.

This is the first time

pack ice killer whales

have ever been, ever been recorded.

- Leigh continues to listen to the group for several hours,

as they look for a suitable meal.

- Typically, killer whales are quiet

when they're searching for prey

because sound travels incredibly well in water,

and so they could alert their prey to their presence.

What's interesting here, because their prey is out on the ice,

it seems these pack ice killer whales are OK with vocalising,

and that's never been known before, it's completely new.

Literally, what we're hearing this second is new.

We're watching searching for prey happening

and the animals are being very vocal.

Those seals have no idea.

It's amazing.

- Somehow, the killer whales understand that seals on ice

cannot hear them vocalising underwater...

..so they can communicate freely,

knowing it won't scare their prey away.

Finally, the whales find a crabeater seal.

They may be the most abundant seal in Antarctica...

..but they're small and feisty,

so sit low on the killer whales' menu.

Jenny tentatively tips the seal into the water.

- Oh, he just went in.

He's back out, he's out. He's in the middle.

- The calves attempt to topple

the seal off the ice.

Now, Jenny uses her teeth to gently

pull the seal into the water.

- The same way that we can hold something very, very carefully

with our fingers,

they're able to do that with their teeth and jaws.

- She moves back and lets the calves have a go.

- You know, it's a visual learning experience,

so I'll show you, and then

I'll hang back and then you repeat.

- Teaching behaviour like this has never been filmed before.

- This could be over so quickly,

and yet, it's drawn out because of

the learning that's happening.

- I think one of them has it in its mouth.

- Using her snout,

Jenny swims the seal away

from the safety of the ice...

- You see how the calf comes next to mum

when she's pushing the seal here.

- ..then releases it again...

..letting the calves

practise the manoeuvre.

- They repeatedly let prey go,

in order for the young to learn,

and that's a real gamble for them

because that prey could get away

and then that's a meal lost.

- Killer whales are one of

only a handful of animals

that actively teach their young...

..and it's the females that take on this duty...

..ensuring the survival of their family.

- Mothers and grandmothers and aunts

take a lot of time teaching their offspring exactly how to do

these complex behaviours.

Similar to us as humans, they have culture in their society,

in that they're passing on information to one another

that is benefiting not only themselves, but other group members.

- Killer whale culture relies on

this transfer of knowledge

from generation to generation.

It's how pack ice killer whales have developed

the most sophisticated hunting strategy on the planet.

But to learn from the queen of wave-washing,

the team must find Gertie.

Over the next few days, they put everything into looking for her.

They spot a group of killer whales...

..but it's what they've left behind that interests Jess.

- It's just this sort of diffuse sort of cloud that comes out

from behind the killer whale.

And you have to look really close.

Otherwise, you'd miss it.

But Sam said he's seen it, so...

..let's go get it!

- If they reach it in time,

Jess will finally be able to analyse

the health of the whales.

But they must hurry.

Scat breaks up quickly in water.

- Are we sure we haven't run over it?

- Yeah. I mean, the piece we saw was literally like

my fingernail size, if that. - That's all I need.

There's no way we're finding that again.

- Oh, here. Here, here, here. There, there. There. - Right there.

Let me just... Go forward, forward, forward, forward.

Got it. - She got it.

- Got it. - She got it.

- World first.

This has never been

collected before.

It's the tiniest little bit of scat,

but my favourite part is it's noninvasive research.

So...

..I'm pretty...

What do you say, "chuffed"?

- Do you say chuffed? - I'm right chuffed!

Whoever thought somebody would be this excited over a poo?!

- Woo!

- But for Jess to be absolutely sure,

she needs to find killer whale DNA in it.

This has never been done on a boat in Antarctica.

- In theory, that tiny little bit of what looks like water

should have the DNA in it. Should have.

Doesn't mean it does,

but it's supposed to.

OK. Erm...

Moment of truth.

I'm going to hit the green button.

I'm really nervous.

Ah! It's sequencing.

So there's DNA in it.

It worked.

It's just insane that that can be processed

inside of the cabin on this tiny little ship

that's rocking around in the Southern Ocean.

- The presence of DNA is huge.

It means Jess will be able to test for contaminants or parasites

and analyse the stress levels of the killer whales.

She's got her science gold...

..but Leigh is yet to find his.

With time running out,

they must make a decision.

Stay where they are and hope that Gertie appears,

or travel to a new spot

and begin their search afresh.

- Right now, we're in no man's land,

but the journeying between sites

is eating up the few hours we have left.

- What's your gut? You got five seconds to decide.

Three, two, one.

- Stay.

You can make all sorts of plans,

but sometimes, you have to go with a gut instinct.

The killer whales forage in this area. If we stay,

they'll be there. It's just about waiting.

We're only looking quite literally for a handful of animals...

..so the magnitude of the task...

..has become very real for everyone.

When you feel like there's time pressure,

it's as if time goes even more quickly.

I definitely feel that, and I'm aware of that as each day passes.

We're all chomping at the bit to really get that one more chance.

- You guys have eyes on her?

- I think I've got them.

I've got them.

- OK, I see them.

Oh! It's Kinzel.

And it's Gertie.

This is incredible. Really brilliant.

- Leigh can once again study the whale that's taught him the most

and embodies everything that makes pack ice killer whales

so extraordinary.

- It's rare for me to feel I have a bond with an animal.

Seeing her with her son

and Georgie, I do feel I have that link to her.

- Like her namesake,

Gertie is also a grandmother,

and all three generations are here.

- They have so much personality.

It's really incredible to watch them just be a family together.

- OK, I'm going out with acoustics.

The thought of recording Gertie is...is...

..it's really cool.

And there's a lot of vocal behaviour happening.

Lots of whistles between Gertie and Georgie,

as they establish and keep that family connection.

- They're swimming up to that crabby

that's on that flat piece of pack, aren't they?

- Guys, they're going to line up on this crabby

that is ahead of you, Dave, by about 300 or 400 metres.

Sam, Sam, get ready for a hunt.

- Here they come. Here they come.

- Gertie leads her family to a crabeater seal.

- Spy-hopping the seal.

- She's spy-hopped this berg about seven times from all angles,

but now there's about four or five other animals coming

just behind this berg.

Did they leave it?

Yep. They've moved on.

- Like all pack ice killer whales,

Gertie can differentiate seal species.

But what really sets her apart

is her exclusive focus on Weddells,

the seal that offers her

the highest chance of success.

So, she leads her family on.

- Red Zodiac needs to turn left 90 degrees, Dave.

- Being in the Zodiac in that moment,

as killer whales come right underneath the boat,

I'm very aware that they are incredibly intelligent

and powerful animals, and if they wanted to,

they could flip us over in a heartbeat.

You just sort of sit and you wait,

and maybe once they've finished popping up and having a look

and they move away, you kind of release a breath!

- They have just dived, so they're not at the surface any more.

- Suddenly, the whales dive,

disappearing from view.

Leigh listens in to try and figure out what's happening.

- It's completely silent at the moment.

I'm not hearing any calls at all.

But any data that we collect,

even if it's silence,

that silence is actually valuable in telling us something.

Oh, I see them now. They're just coming up.

Ah, red. OK. There's something

definitely with blood.

- Gertie has just caught a seal in open water.

This explains her silence.

She's demonstrated being capable of more than just wave-washing.

- This is exceptional.

- It's why Leigh learns more from her

than any other matriarch.

- So travelling this way. - Yep.

- With so many mouths to feed,

the family quickly move on.

- OK, I have got a seal at our 11 o'clock.

- A Weddell seal.

Gertie's preferred prey.

The killer whales' eyes, either side of their large head,

give them a 300-degree field of view.

They quickly realise the seal

is protected by ice on all sides...

- That piece is enormous.

- ..so they push it into open water.

- We can really hear the excitement

start to move through the group,

especially the younger animals.

When they've really found the prize that they want,

then it's about coordinating what they're going to do.

- Oh, they're washing, they're washing!

- This time, Gertie uses a subsurface wave,

its force focused on breaking up

the ice from underneath.

The next wave is deployed

to wash the seal to the edge.

Weaker and less agile than a leopard or crabeater seal,

it takes the Weddell seal

much longer to climb to safety.

But there's a problem.

A submerged shelf prevents

the whales getting close enough

to pull the seal into the water...

..and a raised ledge blocks their

waves from washing it off the floe.

Gertie needs a new plan.

- They are being very vocal,

which is allowing them to co-ordinate themselves.

- Firing bubbles from their blowholes,

they manage to break the shelf...

..bringing the seal inches from their grasp.

- Killer whales are incredibly intelligent,

and we're watching them problem-solve, as the hunt evolves.

- And with one final wave...

..the seal...

..is theirs.

- That was one of the most remarkable things.

You can see them processing

the shape of the ice, what to do about it, how to work as a team.

Like, you can watch them thinking about it.

- I've seen different pods take on prey in different situations

and have different levels of success,

but when I watch Gertie and her group,

the efficiency with which they hunt

really shows that she's at the very top of her game.

She's learnt amazingly well from whomever her mother was

and she's passing that information down on to her offspring,

and they, hopefully, will become just as successful as her.

- That was insane. I don't know how anything I ever see in my life

is ever going to compare.

- That is a life experience, right there.

- During the hunt, Gertie changed tactics multiple times

to be as efficient as possible.

Now, she and her family

share their prize.

- Seeing how skilled

Gertie and her group are

really shows they truly are

the apex Antarctic predator

and one of the most fascinating

types of killer whale on the planet.

- After Gertie's masterclass in hunting,

Leigh's personal mission is coming to a close.

- This habitat...

..and Gertie there,

it just makes it all so worth it.

Gertie has been the essential key

to my knowledge and understanding of pack ice killer whales,

because I've been able to learn

not only the techniques that she's using

in teaching her family members,

but see how she's able to change

that behaviour, based on

different situations.

- In their short time in Antarctica,

the team has learnt a huge amount.

- It just takes so much planning, so much time,

so much effort, by so many people,

and it's come together.

- Leigh has begun to decode

their complex behaviour.

- They are like old friends.

You know, I've spent so much time searching for them,

and every little bit of data we get is a huge win.

- Jess has what she needs to investigate the health of the whales

and the place they call home.

- I have all of my samples and I have the data,

and there's a lot of it, which is great news.

But now, I've got a lot of work to do.

- And with their unique perspective,

the camera team has revealed

how matriarchs transfer knowledge through the generations.

- They are so curious

and so intelligent, and you just have to sort of sit there and enjoy

the pleasure of making eye contact with one of the most

incredible mammals in the world.

- But Antarctica is changing.

These pack ice killer whales

face an uncertain future.

- If we were to lose pack ice killer whales,

not only would we lose an incredible apex predator...

..but we would lose this

incredible hunting behaviour

that has clearly been learnt over

many thousands of years.

- The team hopes that the data they have collected

will help deepen our understanding

of these extraordinary whales

and their unique culture...

..before their way of life

is lost forever.