Animals Up Close with Bertie Gregory

The wind speed is 38 knots. 38 knots.

Okay, the killer whales are coming up

on a chunk of ice with a seal on it.

Oh, no, poor penguin. Get out of the way.

Here we go.

You can see when they're ripping alongside each other,

they are stacked up right next to each other.

Oh, my word! Look at the size of that wave!

I've been all over the world as a wildlife filmmaker.

The best stories are often the hardest to get to.

This one is no exception.

Ooh.

Try not to fall in. I wouldn't last long.

I think that would be pretty much guaranteed death.

We're heading to the icy wilds of Antarctica

to film a group of killer whales with one of the most sophisticated

hunting strategies on the planet.

We have to cross the Drake Passage.

One of the roughest stretches of ocean on Earth.

I've done this journey 10 times, and it never gets easier.

Many seafarers have died crossing these waters.

Definitely feel very, very tiny out here.

To think what it must have been like to be the first explorer coming down here.

They must've just had a serious hunger for exploration

and bucket loads of bravery.

It takes six days and nights to reach a special part of Antarctica.

Home to a group of killer whales scientists call "B1s."

I'm going to use my drone to film them hunting from above.

Cinematographer Tom Walker will be operating

a stabilized camera system to cover the action at surface level.

We have supplies for five weeks, so it's all hands on deck.

This place is like another planet. We're in the land of icebergs

and mountains and...

There's a little penguin as well. A little chinstrap penguin.

And although this place looks really beautiful, it is hostile.

If we were left on land, we'd survive hours,

if we fell in the water, we'd survive minutes, but fortunately,

we've got this amazing expedition sailboat to support our mission.

To maximize our chances of filming B1s hunting,

we need to find a particular type of ice.

So, we'll be working in an area known as "the Gullet."

It's an icy labyrinth of narrow channels running northwards up

to an impassable ice sheet.

This acts like a giant ice-maker. As winter turns to spring,

chunks break off and drift down the Gullet.

Weddell seals, the B1s' favorite prey, use the ice to rest between feeds.

At least, that's how it's meant to work.

I expected this spot right here to be full of ice.

Not just icebergs, but sea ice. This whole area frozen. And it's not.

This year's different. So, we're gonna have to go further deeper

into Antarctic waters to see if we can find the killer whales.

We've also got a world-class spotter on board.

Leigh Hickmott is a whale biologist.

He has a map of B1 hotspots for us to check out.

Okay, I've got some whales.

Looks like three animals direct ahead.

Leigh has seen this family of B1s before.

The group is led by a female, a mother, and she lives with her children.

- - Lovely to see how they interact.

They're clearly very close, they're rubbing against each other,

brushing their pec fins and their heads against each other's backs.

Amazingly complex social structure that works together and lives together.

Matriarchs can live up to 90 years,

and pass their knowledge down to their young.

She's leading them further up the Gullet in search of food.

Oh, this is more like it.

Suddenly, the action has stepped up a gear.

The family speed up and fan out,

pushing their heads out the water as they pass the ice.

This is called "spy hopping." They're looking for seals.

They almost look like a jack-in-the-box the way they're going, "Boing! Boing!"

Well, they have found a Weddell seal.

Here we go.

Weddell seals can weigh up to 500 kilograms, 1200 pounds.

They're large and bulky.

Once in the water, they're often an easy catch for B1s.

They're all spy hopping around it.

Just trying to figure out

how they're gonna get this seal off the chunk of ice.

These killer whales have a trick up their sleeve.

They're picking up speed and using their tails to make a weapon.

Wow! Big dumper.

Seal just about managed to stay on the ice floe.

This hunting technique is called "wave-washing."

B1 killer whales are the only animals on the planet that do it.

They're lining up for another wave.

- Wave-washing! - Wave-washing!

Ooh! So powerful.

But each wave they make, little chunks of that ice

are breaking off and the seal's lifeline is getting smaller and smaller.

You can see the three-year-old calf really is part of the hunt,

learning how to wave-wash from mom and grandma.

Oh! It's in, it's in.

No, it's back out.

- - They got it.

The unbelievable intelligence that these animals have.

- - It's a really cool strategy.

- - This really is...

nature's ultimate predator.

It's awesome to see this family wave-wash,

and see it being passed down the generations.

But they're part of a shrinking population.

It's estimated there are only 100 B1 killer whales alive today.

The major reason for this is ice. Or rather a lack of the right type of ice.

I'm diving down for a closer look.

We've posted lookouts in case the killer whales choose this moment

-to come and say hi. -

And with the water below freezing,

I'm keen to make this quick.

There's gotta be easier ways to earn a living.

First up is this classic Antarctic iceberg,

which has broken off a glacier.

Stand by, stand by, stand by. Okay, yep.

The scale of this iceberg is just crazy.

I mean, it's huge above the surface, but underwater, it's just massive.

It goes down as deep as I can see. And almost all of it is under the water.

And as beautiful as this iceberg is,

it's not the type of ice we're looking for.

We're looking for sea ice, so I'm gonna keep going this way.

Sea ice is very easy to spot,

mainly because so little is visible below the waterline.

Well, this is a big chunk of sea ice. And you can see how, underwater,

it's a totally different shape to the iceberg.

It doesn't hang deep, it hugs the surface in this thin, skinny layer.

And because it's this lovely skinny, flat shape,

it makes it a really good platform

for the seals to jump out of the water and to rest on.

But while it's a great place for the seals to rest,

it also means the killer whales can get very close to them.

It doesn't take them far out of harm's way.

Flat sea ice is essential for the B1s' wave-wash attacks.

But the problem is, it's getting harder to find.

Sea ice has been steadily disappearing over the last decade.

You might think this place looks cold,

but Antarctica is one of the fastest warming regions on Earth.

We managed to find the family of three females again

as they search for prey.

No flat ice should mean no food for them.

But these intelligent predators

are always on the lookout for any opportunity.

Okay, there is a seal. That looks like a Weddell seal as well.

There are two killer whales next to the seal at our two o'clock.

Very close, Bertie.

Okay, they found it.

This is glacial ice, so it runs deep below the surface,

and the B1s can't swim underneath. Wave-washing is not an option.

Oh. So, they've got the seal pinned right against the chunk of ice.

There's a little ledge that the seal's using

to get its hind flippers on.

You can see the killer whales trying to sneak 'round the side,

trying to grab its hind flippers.

Oh. They got it, they grabbed it. They man... One of them managed

to get around the back of it and grab its flippers

and they've just pulled it down. Oh, they let it go.

Well, the seal has spun around to defend itself with its bite.

What are you gonna do, killer whales? You're gonna need another strategy.

They're delicate with the prey

and that seems like a pretty weird thing to say

that such a massive predator would be delicate, but they are.

They're really carefully just trying to nip it and grab it.

Even though they are many times bigger than it,

that seal is still dangerous. It's got a big mouth full of teeth.

A blinding scratch to their eyes could blunt their hunting skills

and ultimately be fatal.

The B1s are switching tactics.

Look at them blow bubbles to disorientate the seal!

- - Oh. Savage.

It's taken a lot of effort,

but the B1s figured out a different way of hunting a seal on glacial ice

-rather than flat sea ice. -

And this one kill is vital for the whole ecosystem.

These apex predators are now providing food

for the other species that live here, predominantly birds.

So, we've got some skua coming down, taking pieces of meat.

We've got Wilson's storm petrels dancing on the water's surface,

just picking off little droplets of oil.

- -

Having fed at last, the family cruises back into open water...

and meets up with more B1s.

Considering there are only 100 known to be alive,

it's magical to see so many in one place.

But how have such a large group come together?

We know killer whales use sound to communicate,

and this is a great opportunity to learn more.

Well, while this pod's in this really mellow, relaxed state,

we're gonna take advantage of that and see if we can record some sound.

The noises I'm hearing sound like something from outer space.

-They're going... -

Can hear them clicking. Click, click, click, click, click, click.

That's echolocation, that's how they see the environment underwater.

Even though the underwater visibility is very bad.

So, they send out clicks that bounce off of objects like ice and the land.

And then they hear that bounce back, and they can use that to create a picture

of their environment, so they know where the land is,

where the ice is, where there might be seals out on ice.

- -Oh, there's a big guttural.

- -

Their calls can travel nearly 10 miles underwater.

Scientists think this is one of the ways B1s swim with perfect coordination

when wave-washing.