(soft music) ♪ (splashing) (narrator) The remote, ancient Kimberley Coast of Northwest Australia.

For thousands of years, humpback whales have migrated here to mate and have their young.

♪ (woman) The drive to migrate is unbelievable.

They're hardwired.

♪ The predictability of their migration gave them a really close call with extinction.

In 1963, there was between 200 and 300 humpback whales in this West Australian population.

(narrator) World-renowned marine biologists Curt and Mich Jenner have studied humpbacks for 25 years.

Their groundbreaking work was instrumental in identifying Camden Sound as the epicenter of the breeding grounds and having it designated as a whale sanctuary.

(Curt) Over the last 25 years, they've now recovered to the point where there's probably 33,000 animals, and obviously, that calving ground is absolutely critical to that.

(dramatic music) ♪ (narrator) Now, Curt and Mich return to the Kimberley equipped with cutting-edge technology.

♪ (Curt) All right, tag's away in a good spot!

(narrator) Using satellite tags, they attempt to follow a female and record the vital first hours of the life of her newborn calf.

Quadcopter cameras prove to be a scientific revelation, giving them a unique perspective on the males' violent battles for dominance.

(Mich) Forty tons of animal whacking against each other, that really does inflict awful injuries.

(narrator) And capturing an extraordinary event, the victor's courtship of a female.

(Curt) Really, we haven't seen anything like this in the 25 years that we've been doing this, so it's pretty incredible.

(narrator) Their new night vision cameras reveal a desperate battle in the darkness as a mother tries to protect her calf from marauding males.

(Mich) These males could breach on top of that calf and crush the calf.

♪ (narrator) It's an expedition that will change their understanding of the place they call the Birthplace of the Giants.

♪ (orchestral music) (Curt) One out the bow, coming up the bow!

(water hissing) ♪ (splashing) ♪ (giggling) (Mich) Wow!

♪ Look at that!

Oh my goodness!

What a sound!

(Curt) Oh, look at that!

♪ -Listen to that!

-Unbelievable!

(Mich) Wow!

Oh, wow!

(dog barking) They just wanna see what we are!

(Curt) Ah, wow!

Woo-hoo!

(Mich) This is when the whales come and find you!

We don't even have to find them!

♪ (Curt) And we have the stern, the back again!

Look at you!

You're a funny whale!

-Oh!

-Wow!

-Look at that!

-Wow!

It's moving right here!

Oh my goodness!

♪ Wow, look!

I can barely see-- look at it!

(camera shutter clicking) (laughing) What a beautiful experience!

Just a wonderful afternoon studying humpback whales!

♪ (narrator) To get to the Kimberley, the humpbacks have made an epic journey.

♪ It begins in their summer feeding grounds in the Antarctic.

(soft music) ♪ After three months of feeding to gain body weight, they set off for the Kimberley.

Their round trip of nearly 13,000 kilometers is one of the longest migrations of any animal on the planet.

They'll remain in the Kimberley breeding grounds for months and won't feed again until they return to the Antarctic.

♪ (horn blowing) (Curt) Okay, let's take that bowline off.

(narrator) Aboard their ship Whale Song, Curt and Mich begin the journey to the Kimberley from their home port of Fremantle.

(solemn music) (waves crashing) ♪ (Curt) The front that we're trying to escape and that the whales, ultimately, are trying to escape as well, come over the top of us and we had a bit of a rough start to the day.

(splashing) ♪ Humpback whales are an interesting animal.

They've obviously figured out, over thousands and thousands of years of evolution, the right way to do things.

This time of year in the Southern Hemisphere, we've got nothing but nonstop storms.

Every three days, another storm front comes through, and that makes the water rough and it also brings cold water up from the Southern Ocean, and that's not good for giving birth to a newborn calf.

They have very little blubber on them, and the more successful animals are born in nice, warm tropical waters with almost dead, glassy calm, and that's what we're heading for.

And the whales know that.

(waves crashing) (narrator) The humpbacks are no longer hunted here, but they still face life-threatening hazards on their journey.

(piano music) One of those hazards is running into commercial fishing gear.

Whales entangled in fishing gear can die from drowning or from shark attacks as they lie trapped.

Some die slowly and painfully from the rope wounds inflicted in their struggles.

But help is at hand.

(soft rock music) ♪ Wildlife officer Doug Cochran is a world-leading expert on whale rescues at sea.

(Doug) One of my main roles is basically to disentangle whales that are in trouble.

We have a whale entangled in lobster gear.

We'll go for a cut that'll do a total disentanglement.

So everything's safety, safety, safety, all right?

Whales are beautiful animals, but they're also large wild animals.

A 40,000 to 45,000 kilo animal, how do we manage an animal so powerful?

This whale is anchored, so I can't attach a control line, which gives us a solid attachment.

Being so sensitive as they are when they've come into contact with ropes and lines, they most often panic.

(tense music) ♪ (indistinct remarks) (narrator) Doug uses a pole-mounted underwater camera to assess the entanglement.

(Doug) Okay.

(water bubbling) The rope, in fact, is like a mass of twine making one thick rope.

And we know from experience that even a simple entanglement will kill a whale.

(narrator) Doug's inspection reveals another, bigger complication.

-Big girl, eh?

-Yeah, it's a girthy animal.

(Doug) It's obvious to me, it's so rotund, I'm dealing here with a pregnant female.

If I don't get this rope off quickly, who knows whether she's going to be able to deliver her calf and not abort.

(solemn music) At some stage, the animal wants to rest.

That gives us a little window to get in close and hopefully get one shot.

I can see that I can get that blade under the right side of the wraps.

(indistinct remarks) ♪ (splashing) -One good, clean cut!

-She's free!

(orchestral music) (Doug) It's come free, it's making a bolt for it.

What I saw at the last moment was all that gear drop.

-Well done.

-Well done, guys.

(narrator) But the rescue isn't the end of the story.

(Doug) You know, once we've now freed her, it's still a big question: Will she make it?

Will her calf make it?

(narrator) Doug's rescued over 60 whales, but he's never been able to find out if any of them have survived long term.

The only way to be sure would be to have a confirmed resight of a whale he's freed.

But to Doug's knowledge, that's never happened in the Southern Hemisphere.

(soft music) ♪ In Camden Sound, Whale Song and her crew are on the hunt.

(Curt) The main objective of this exercise is to actually put a tag on a humpback whale that's pregnant to track to the point where she actually gives birth, and then follow her through the calving grounds.

♪ They can be fairly elusive, particularly these cows, they really do not want attention.

Best thing to do is to have people up on the top deck.

Carrie's up there, and they're looking in all directions.

♪ (narrator) Eventually, a likely whale is spotted.

(Curt) The best way to tell whether these animals are pregnant or not is to look from behind down the middle of their back, and the animals that are pregnant are almost flat across the middle of their back and they look like you could pretty much drive a truck down them, they're so big and wide.

(camera shutter clicking) (Mich) Look at the photo on the back here!

-So broad!

-Wow!

She's definitely pregnant.

This is it.

(dramatic music) ♪ (narrator) The whale will be tagged from the ship's inflatable.

♪ Research technician Simon will fire the tag.

(Curt) The tags we're gonna use for this project are quite new.

There's two little prongs on the tags and they attach into the dorsal fin of the animal, and so they're quite benign, they don't disturb the animal at all.

(suspenseful music) Foremost in our mindset when we're approaching a female is to not disturb her.

If you do it wrong, the animal can be upset.

Hold on, hold on.

Not a good one, not a good one.

The animal is pregnant, and of course, we're approaching her with an air rifle, putting a dart in.

♪ Good shot, good shot, mate.

All right, tag's away in a good spot.

-Made way.

-Yes, woo-hoo!

Time, 13:54.

All good, but let's grab the arrow.

(Curt) That was some of the most exciting stuff that we could ever do in our lives.

We actually really don't know where she's going to go, and that's the real mystery here.

That's what this tag's gonna tell us, it's gonna tell us how they use the sanctuary, and that's really important.

(Mich) We called her Willow.

It really has been years in the making that we've been thinking about tagging a pregnant female and following her here in the calving ground.

♪ (narrator) Doug's day hasn't begun so well.

(somber music) ♪ (Doug) A humpback sub-adult female came ashore and is now beached high and dry.

♪ It's a whale in big trouble.

♪ It's come ashore basically in a starving condition.

Sinking along the flanks of the whale indicate to me that the body reserves, basically the fuel tank is empty.

Now that it's up on the beach, what's happening internally is their temperature goes up.

Well, this is multiplied by the fact that the outer covering of the body is in fact a coat of blubber that retains heat, basically cooking it from inside.

♪ The sun blisters the skin, similar to what happens to very bad burn cases, and it's slowly being tortured to death, basically.

(groaning) (Doug) Yeah, poor bugger.

(indistinct remarks) ♪ (Doug) It is not a viable animal to rescue.

It's not gonna swim off, because it's not an animal that's in a healthy condition.

So I want to end the suffering now.

♪ Cranium implosion technique involves a pyramid of charge.

The charge is dampened by sandbags that are soaked in water and that focuses that charge directly into the brain and disintegrates it in a nanosecond.

They're now ready to detonate.

(solemn music) I personally feel very sad for this whale.

When you look into the eye, you know there's a soul behind that eye.

So it's pretty hard to deal with from a personal point of view, but I look at it from this perspective: We have a moral responsibility to treat this whale with dignity and respect and also humanely.

♪ (indistinct remarks) -All clear!

-All clear!

♪ (explosion) (Doug) That's it.

-You're happy with that, then?

-Yeah, thanks, mate.

-All clear?

-Yeah, all clear.

We've treated this whale with respect, with dignity, and have delivered an instant death.

♪ (motor whirring) (narrator) With his sad task over, Doug has traveled to join Curt and Mich's expedition.

It's an exciting opportunity for him.

(Doug) Well, in my 35-year career, I've never been to the calving grounds in the Kimberley.

I'll be looking for the condition of the humpbacks, any injuries that are caused by fishing gear.

Even a single rope does leave a scar.

(narrator) Doug's first task is to help them find Willow again.

(Mich) Where are you, Willow?

(soft music) ♪ (narrator) Even with the tag, it's not simple.

(Curt) We'll be getting what we call a fix, a positional location from the tag about every 45 minutes to an hour.

It's not a continuous signal like a radio tag would be, so it actually has to come to the surface, send a signal then from the tag up to a satellite.

It depends on a satellite being overhead.

It will give us a position somewhere within a kilometer.

That kilometer is a big patch of ocean.

We've got Doug up top with an aerial, so he's sweeping the area trying to listen for a ping on a handheld radio.

(Doug) We have a lot of white noise at present, and you'll get a dip in that white noise.

(radio static) Got it, we're in business.

Once we get a signal on Doug's antenna, then it's up to the visual team.

♪ (camera shutter clicking) (Mich) There we go, there she is, that's her!

The black and white marking on the underside of the tail fluke is just like our fingerprint, so unique.

We have three photographs that we use to describe the humpback whale, and it's the right dorsal, the left dorsal, and the tail fluke.

With these, we can resight an animal, so we've resighted Willow because that tail fluke is only unique to Willow.

(narrator) Photos are also a vital tool for whale research.

(camera shutter clicking) (piano music) (Mich) When we're doing these behavioral studies, every sequence that they come to the surface, we can use the photographic evidence of who's there, who's doing what, and what's the timecode that those animals are surfacing?

I'm taking between 3,500 and 4,500 images each day.

(narrator) The photos are matched to research assistant Carrie's logs.

15:08, they were down for five minutes.

We're logging all of their behaviors, everything that they do every time they come to the surface.

(narrator) These records have made Curt and Mich world leaders in understanding whale behavior.

♪ And Willow is behaving very oddly.

They've never seen this rolling and arching behavior before.

(Mich) This could be a good indication that she's fairly close to giving birth to her calf.

It could well be that she's just trying to get comfortable.

She might be just moving the baby around inside and just trying to help the passage.

(splashing) That was a peduncle slap, that was a rather active behavior.

What's that all about?

(narrator) To try and find out, they'll follow Willow into the night.

It will be the first shakedown of their new night vision technology.

(mellow music) (Curt) To be able to have the technology to allow us to follow them into the night is fantastic.

It's such an eye-opener into the world of a whale.

You know, with 5 percent of their life that's spent at the surface, but half that time is at dark, then really you can only see them for two and a half percent of the time, and so we're gonna try and claw that two and a half percent back a little bit.

(whooshing) (Mich) We've seen quite a number of unusual behaviors.

The female is quite active for a whale that's just about to give birth.

♪ She keeps on doing these peduncle slaps.

And the peduncle is from the dorsal fin down to the tail flukes, and the peduncle is hitting on the surface of the water, and this makes a great big splash, and it's a very aggressive behavior.

(splashing) Some of the stuff that we've actually seen so far is behavior that we've never really watched for this long before.

We've certainly followed pregnant females before and watched what they do, but not for this long.

Time will tell whether they're actually precursors to labor.

(narrator) But the weather is making life difficult.

As the wind increases, Willow is lost to the night vision gear amongst the waves.

(waves crashing) She's now only visible on the thermal camera, which picks up her body heat.

(Curt) How long we can hold this depends on how happy they are to be sitting still.

If they want to have a run, then we'll really struggle to keep them for the rest of the night.

(narrator) But Willow does just that.

She runs over a reef between two islands.

It's too dangerous for the ship to follow.

By the time they round the islands, there is no sign of her.

(Curt) The satellite tag has given us one fix so far.

That fix wasn't a very accurate one, unfortunately.

Obviously, the whale didn't spend enough time at the surface.

Once we lose our visual cues, we're down to using instruments only, and we're having trouble.

♪ (narrator) There is no alternative but to abandon the chase for the night.

(Curt) We'll let the satellite tag do its thing overnight and we'll regroup in the morning.

We're gonna anchor out here, and we'll be here in the morning.

♪ (piano music) ♪ (narrator) Morning brings bad news.

Willow's latest satellite fix is over 30 nautical miles away.

Curt's made a big call.

He's not going to give chase.

(Curt) We made the decision to watch her basically on our computer screens.

She's giving us positions on a regular basis, and we felt it was probably best just to let her track along independent of us and our cameras et cetera following her so that she had a peaceful first few days to her life with the new calf.

(narrator) He'll rely on Willow's tag to fill in her story, and the expedition moves on to a new phase.

♪ (Mich) It's early in the morning, and we found a cow-calf escort pod, and this pod is just lying at the surface here.

Logging is what we call it, and it's literally because she appears to look like a log at the surface.

(mellow music) ♪ They're all just having a beautiful morning snooze!

Well, why wouldn't you?

Sister Kimberley is absolutely spectacular today.

♪ (Curt) One of the interesting things about the way we're doing this right now that I don't think we could do with any other boat, including even our small inflatable is to stay this close and not impact the whale.

And it's about the sound that the boat is making.

We have a very low noise signature with this vessel, and it's been measured by the Australian military as being one of the quietest boats probably in the Southern Hemisphere if not the world for its size.

♪ (narrator) But there are limits to how close even this ship can get, and one piece of technology is about to prove to be a revelation for their studies.

(Curt) One of the things that's always intrigued us about cows and calves is, when they're resting, how do we tell whether the animals are asleep?

What are the body postures that we're looking for?

How do they interact with the calves?

Are the calves feeding continually or just every now and again?

And it occurred to us that one of the only ways that we could do those sorts of observation was from overhead.

(soft music) (drone buzzing) We've started using these quadcopters quite cautiously.

We applied for a permit, of course, to approach to within 300 meters to see how they react, and we're happy to report that we've seen absolutely no reaction to the quadcopter at all.

They seem oblivious to it, almost like there would be a seagull overhead.

♪ To try and do these same sorts of observation techniques from a standard aircraft like a helicopter or even a fixed wing plane would be impossible.

I think it's a fantastic advance in our research.

♪ You can see that the animal, in fact, when it sleeps, is completely asleep.

The pec fins are hanging straight down from the body, the tail fin is actually curled and lying down, straight down in the water.

That's a really relaxed animal.

♪ The important thing about resting, of course, is the female is saving her energy, but also it's about the energy that the calf has consumed, the milk that she has made from that blubber supply, and turning that into blubber reserves on the calf.

And so the calf actually needs to sleep as well.

♪ (Mich) It's essential that these cows and calves rest while they're here in the calving ground, because it's an enormous journey that they need to make back to the Antarctic.

♪ (narrator) Some behaviors below the surface are almost impossible to make out from on deck.

The calf disappears.

But seen from the quadcopter, it's obviously directly underneath its mother.

There's only one explanation: it's feeding.

(Mich) It's really fantastic, because we've got the exact timing that the calf was under the cow, and we can match it with this aerial footage, and we know for sure now that this calf was suckling.

(piano music) ♪ What we're able to see here is the closeness and the beautiful tactile relationship that occurs between a cow and a calf.

And this is the strongest bond in a humpback whale society.

♪ Really interesting thing to observe is the nuances of their behavior.

♪ It was just beautiful to see these tiny, really interesting little behaviors and really close relationship.

♪ (Curt) This is what we need, a very quiet area.

There's actually industry in this area, there's a mining station not too far from us, but it's quite quiet.

They don't have a lot of noise going on on a daily basis, and it works quite well, so I think this is a good mix.

Humans can exist in an area where there's a whale sanctuary, we just have to do it the right way and do it sensibly.

♪ (narrator) The expedition enters the Buccaneer Archipelago, right in the middle of a battle.

(dramatic music) ♪ (splashing) ♪ The Kimberley is not only the humpbacks' calving ground, it's where they come to mate.

♪ But first, the males must decide who's top dog.

♪ (Mich) This is a competition by the males to show the most aggressive behavior and put them at the top of the tree.

♪ They're swiping and thrashing and crashing at each other, and all of this is for the availability of a female.

♪ These whales are doing these underwater blows, so they're exhaling just under the surface, and it creates these beautiful bubble trails.

♪ This is the way that you show the other males how big and wonderful you are with these big, bolshy, huge, big, aggressive blows.

♪ They're physically whacking into these other animals.

♪ Forty tons of animal whacking against each other, that really does inflict awful injuries.

♪ (splashing) (Curt) We've heard stories and we've seen photos of these battles ending really badly for some of the whales.

The dominant animals will come out and breach.

♪ One landed in Hawaii on the back of another male and broke its back.

(splashing) (Mich) What's really amazing to see with these whales is how mobile they are and how agile.

They're just twisting and turning just on a dime!

(solemn music) A 40-ton whale, 17 meters long, and they can be roaring along at one direction and then quickly turn.

It's just wonderful to see.

♪ (narrator) This agility is down to their huge pectoral fins.

Not only the biggest of any whale, but with the lumps or tubercles on the leading edge reducing drag, one of the most efficient shapes in nature.

♪ Efficiency is combined with enormous power.

The muscle that powers the tail is the strongest in the animal kingdom.

♪ There will be no letup until a victor emerges.

(Mich) It's a really long endurance competition here.

They can be five, six, or seven hours, so the males are in for it for the long time, but they're gonna win a female at the end, so I guess it's worth it.

♪ (narrator) After all the chaos, something strange.

(piano music) A whale's tail fluke sticking out of the water.

This behavior called "tail sailing" isn't often seen.

The quadcopter gives a new perspective on this mysterious behavior.

♪ Nobody knows quite why whales do this.

Could it be a cow giving birth?

♪ No, her calf pops up.

♪ The calf dives down to feed, so this may simply be the position in which this mother prefers her calf to suckle.

♪ With a belly full of milk, the calf is full of energy and decides to try out this tail sailing for itself.

(playful music) ♪ It's harder than it looks.

♪ It just can't get its head to stay down.

♪ (splashing) Time to give up.

But the cow is still going.

She might be too hot.

The blood vessels in her tail fluke are close to the surface, so as the breeze cools the blood here, it flows back and cools her down.

As she comes up, she's surrounded by remora fish.

Remoras eat parasites off the whale's skin.

So she may have been hanging upside down to let the remoras do their work.

Wow!

(camera shutter clicking) (bright music) Coming right up beside us!

This is what we call whale cricket!

Where you run from either side of the boat all the time.

♪ I've already taken 600 photographs.

(laughing) (soft music) (narrator) Despite all the fun, there's a serious message in this behavior.

(Mich) This whale is a large animal, but she's definitely not pregnant, but it looks like she's desiring to be so.

♪ So she's thwacking her pec on the water like that.

Incredibly percussive sound.

That pectoral fin is five meters long, it's the same as our arm, all of the same bones, the phalange bones and all the same arm bones.

Look at that!

And thwack on the surface.

And that sound is so loud and that sound carries.

All the whales in this area know that she's available.

She's letting them know with this pec wave and pec slap like that.

♪ (splashing) She's pretty good at this game.

She knows when she's doing that that this will bring the males in.

It's very obvious and it's very clear, that, you know, this is how we operate in the animal world.

(narrator) And sometimes she gets more than she bargained for.

(dramatic music) ♪ One female has picked up a whole group of admirers.

♪ (Mich) It looks like they're all stacked up following a whale that we're calling Embee.

♪ Embee turns, then the entire pod turns.

Really, their focus is all about her, so she's kind of winding up eight other individual whales, and all of their attention is on her.

But she's obviously quite a hot property.

♪ (narrator) There is a definite pecking order of the males.

(Mich) It's really interesting to look at the literal positioning of the whales.

You get a primary escort, and that whale actually has prime location next to the female, then there'll be a secondary escort literally just a little bit further back.

And then there's a tertiary escort.

It's really interesting to see this whole tiered effect.

♪ It can be that the primary escort doesn't actually hold that position, so they can fight for several hours to be the primary escort literally with the prime access to the female, but then there'll be a secondary escort that may come in and usurp them, so they've really got to look over their shoulder, keep checking what the other whales are doing, and then still keep focusing on the female as well.

It's a really hard-won battle, and when they win, the reward is great.

♪ (narrator) And then the quadcopter captures something Curt and Mich have waited a quarter of a century to see.

(Curt) Okay, we've identified this whale as the focal female.

And you can see now that the male's coming up from below.

It pretty much lifts her clear of the water.

(soft music) ♪ It gets a bit hard to see here, but as they come up, they're locked together, and you can see that they're belly to belly.

♪ I'm pretty convinced that this was a mating or at least a mating attempt.

I guess we won't really know whether it was a successful mating unless we see a calf with this female next year, but we'll certainly keep our eye out.

♪ The more I look at this footage, the more I am convinced that this was a mating attempt.

♪ And really, we haven't seen anything like this in the 25 years that we've been doing this, so it's pretty incredible.

(narrator) A spectacular day ends equally spectacularly.

(calm music) ♪ (bird chirping) (air blowing, screaming) That was right here!

(laughing) They're right here!

That's fantastic!

Look, they're coming up!

It's just amazing!

Gave me a fright!

Right there.

They're glowing gold in the tangerine sun!

What a treat!

(water lapping) (waves crashing) (dog barking) (Curt) We've lifted anchor this morning.

Within about half an hour, we've come across a cow and calf.

(soft music) (Mich) This island is called Miawaja, so we've decided to call the cow Mia and the calf Waja.

A cute little poppet!

♪ They've got all these little sensory tubercles on the tip of their rostrum and the forward pad of the rostrum, and it makes the calf look like a little dill pickle.

What they're doing is giving information about the water temperature and water quality, so a single hair cell involved in that system.

Humpback whales are mammals, they're marine mammals, and as you know, you need to have hair to be a mammal.

So this is the hair on a humpback whale.

♪ (whooshing) So little Waja is just at the surface now.

Just got some energy after having a nice little feed.

(playful music) ♪ Humpback whales are the clowns of the ocean, they're the jesters of the sea, and they love to play and roll and fluke slap and crash and bash.

And right from an early start, they begin these behaviors.

Certainly looks like they're having fun.

♪ (splashing) ♪ All of this is all about conditioning for the journey south.

Really feeling all the muscles, and really getting the whole body toned and trained for the journey back to the Antarctic.

♪ Funny little calf.

(narrator) But the end of the day brings a reminder of the dangers lurking in these waters.

(suspenseful music) (Mich) Goodness, what was that?

Did she do a peduncle slap?

(camera shutter clicking) Wow, two peduncle slaps!

♪ Oh, calf breaching!

♪ Okay, so we've gotta really watch what's going on.

Maybe there's a shark here.

♪ Inverted fluke slapping!

Really loud noise on the water, and it really seems as if she's giving a shark the hurry-along!

Get away from my little calf!

♪ Even though you're a 40-ton, 17- or 18-meter humpback whale, a shark could be a threat.

I know it's kind of surprising for people to think of that, but a shark will just take a bite and swim away.

Little calves, if that shark bites in just the wrong spot, then it could be fatal.

(splashing) (narrator) Mich spots a tell-tale sign that it's the female that's been attacked.

(Mich) There's a slick just over here, and we just came downwind of it, and I can smell that it smells like blubber and maybe this is a little shark has nipped her somewhere, maybe the pec fin or the fluke of the female, and this is what we're seeing in the water!

(narrator) A slick as large as this couldn't have come from the calf.

He's still too young to have developed enough blubber.

(solemn music) As darkness falls, the night vision cameras give Curt and Mich a whole new understanding of the dangers of predation.

♪ (Mich) As darkness fell, it was relatively quiet at first, but then absolute chaos!

(dramatic music) ♪ (Curt) Nobody's really done an in-depth behavioral study of humpback whales at night that I'm aware of.

♪ There's been instances where we've heard breaches in the distance and that sort of thing, but we've never been sure of what's been going on.

Now, with these new night vision tools, we're starting to get an understanding of actually what's going on, and it's pretty exciting stuff.

♪ What we think is going on now is that on dusk, the predators, sharks that are in the area, have probably been circling these animals that are moving very slowly around here, and so they've stalked their target all afternoon, and they take a bite out of the whales.

And so what ended up happening tonight was a fairly spectacular instance of it.

We had repeated breaches over and over and over again.

Maybe the sharks were a little bit more persistent tonight, and they needed to be a bit more firmly chased off, but it was pretty spectacular.

♪ (birds chirping) (narrator) The morning reveals another danger faced by the calves, this time from their own kind.

(soft music) (Curt) Sometimes, the females, after giving birth, are willing to mate again, it seems.

♪ (narrator) Other whale species, like dolphins, excrete hormones that the males sample to determine the female's breeding status.

It's not known for sure if humpbacks do this, but the overhead view gives some new evidence that they might.

These males are constantly maneuvering themselves behind the female, and do appear to be trying to determine her readiness to mate.

But not every female is ready to mate, and that can lead to danger.

(splashing) (ominous music) (Curt) These males are getting a little bit aggressive and probably a little bit too aggressive for her.

♪ (Mich) Paramount in the female's mind is to protect her little calf.

♪ (narrator) Humpback mothers have developed clever strategies to protect their calves.

(Mich) This little calf is rolling around right on the top of Mom's back.

The calf is protected by all of her body, so she's really doing a full body block for her little calf.

Often, they do it literally by putting the calf right on the top of their pec fin.

And they ride along, swimming along with the calf perched up right on the top of their pec fin.

It's really amazing to see, and it's a really incredibly effective defense mechanism that she is keeping her calf away from these males.

♪ (narrator) The calf is carried along in the slipstream of her pectoral fin, allowing her to move fast.

♪ This female blows a curtain of bubbles to divert her calf away from the males.

♪ Even the chase itself is a threat to the calf.

(Mich) The calf will need to feed very often each day, so the longer she engages in these racing and chasing to get away from males, that's time spent without feeding the calf.

(soft music) (narrator) Nightfall doesn't lessen the danger to the calf.

♪ (Mich) Certainly, the calf is in great danger when the males are roaring around like that.

♪ These males could breach on top of that calf and crush the calf.

♪ (Curt) This is the first time, certainly, that we've ever witnessed this sort of stuff going on after dark.

So the animals continue their same behaviors day and night, which for an animal that lives in a pretty much predominantly dark ocean, I guess that makes sense.

♪ (narrator) They want to see if the female can keep her calf safe.

Although the darkness is no longer a barrier to following the drama, the landscape is.

(Curt) Unfortunately, the whales are getting up against the side of an island right now.

We've got a lot of uncharted reefs in this part of the world, so we feel that it's a little bit too dangerous to keep following them tonight and we're gonna call it quits.

♪ (calm music) ♪ (narrator) The chase is over.

The calf has made it and is once again feeding, resting, and playing.

♪ (Curt) Coming up.

Woo-hoo!

Wee!

(indistinct remarks) (narrator) Whale Song has found herself in the middle of another pod of fighting males.

(whooshing) (Curt) Right there.

(Mich) That whale's got a fantastic fluke!

This is a pretty noble animal, so White Knight seems a nice name.

And then the one accompanying it has got a gray racing stripe down the caudal peduncle, so Graystone.

(Curt) Oh, what's going on?

They are rolling.

Big blow, wow.

(whooshing) -Wow!

-We're actually one of the pod right now.

Yeah, it's just a very delicate way to drive, and we'll just watch what we're doing, but yeah, it's pretty exciting.

That's Graystone!

-That is!

-That is the White Knight.

(Mich) And there!

(Curt) That's got some power.

Look at him chase that whale.

He's actually actively chasing that whale.

He ran over there, and he actually took a swipe at him with a pec fin, and then he came back over towards the White Knight.

That's Graystone.

That's Mr. Grumpy.

(narrator) White Knight has really caught Curt's attention.

(Curt) We've probably only got about 5% of our whales, maybe even less, in our catalogue that have got white on the top side of the fluke.

(narrator) But Doug can hardly believe his eyes.

(Doug) Wow!

Gotta be you.

When I first glimpsed it, I felt, you gotta be kidding me.

You've gotta be kidding me!

I looked at it and I thought, "I've seen that before," and it's not like it's something you see every day.

When I have an image indelible on my mind from a rescue, they kind of stay there for a long, long time.

When I saw that distinctive white pattern on the top of the fluke, it's just like, "You've gotta be kidding me!"

(soft dramatic music) And I've got images from that rescue.

Have a bit of a comparison and see what we've got.

♪ Have a bit of a look.

♪ If this is the same whale that Doug has rescued last year, this would just be fantastic.

♪ (Doug) It's the same type.

(mellow music) ♪ -Back!

-Back!

(Doug) Back!

♪ (indistinct remarks) All clear!

♪ (narrator) After over 60 rescues in 35 years, this is the moment Doug's been waiting for.

What are the odds, such a big ocean and a population exceeding 30,000 animals, of finding that particular one?

Unbelievable!

(narrator) It's positive proof that severe entanglements are survivable long-term and answers the question that Doug's been asking for so long.

(Doug) It's hard to describe the personal feelings, because I don't think words can explain it well enough.

♪ To contribute to its survival is just, I guess, humbling.

♪ (splashing) (water roaring) (bright music) (narrator) The aerial and night vision technology has given Curt and Mich new scientific information on the lives of humpback whales.

♪ (Curt) Good shot, good shot, mate.

(narrator) Even the satellite data from the tagged female Willow has contributed.

Despite the disappointment of losing her so soon, the tag tells a fascinating story of her first few days with her new calf.

(Curt) One of the things that the study was aimed at was trying to look at how females with newborn calves used this calving area.

And she's used it about as well as you could imagine.

She's gone right around the outside boundary of the entire calving area and then stopped to rest in the staging area before leaving it, which is what we've imagined they do the whole time, and she's actually done it, traced it out on the map for us, and it's given us a great bit of information to talk to managers about the area and suggest extending the boundaries of the marine park.

So it's one of those things that you always hope happens when you start planning a study, but it's actually happened this time.

(soft music) (narrator) In the 1960s, the population of humpback whales in Western Australia was on the brink of extinction.

Curt and Mich's 25-year mission to understand and protect these extraordinary creatures has contributed to one of the greatest recoveries of any animal population on the planet.

It's a mission they intend to continue.

(Mich) Making the journey from the Antarctic where they feed in the kitchen to the bedroom in the Kimberley is absolutely critical in a humpback whale's life.

They need to come here to find friends, and they need to come here to give birth to their calves.

It makes it a really special place.

(dramatic music) (Curt) It may not be coincidental that this is the least inhabited spot on the planet by humans and the most populated spot on the planet by humpback whales.

♪ So it is the ideal sanctuary for these animals.

♪ Now that it's a marine park and protected, it's going to continue that way, so this population is gonna be one of the world's treasures for a long, long time.

♪ (whooshing) ♪ (Mich) The work that we have been able to do has been able to help in the protection of humpback whales in Western Australia, even though it only started out with a deep-down love for humpback whales.

♪ (bright music)