♪♪ MUSTILL: My name's Tom Mustill.
I make wildlife films.
In 2015, I was in a kayak whale watching trip in California, when this happened.
A humpbacked whale breached on top of us.
How can you get that close to something that big and that much power and not die?
I couldn't let it go.
I've come back to California to reconstruct what happened to me.
How come my whale hit me?
Was this an aggressive act?
Could it have jumped on us on purpose?
WOMAN: Please tell me you got that.
[ Screams ] MUSTILL: Then I started to realize there were other close encounters with whales.
HAUSER: He tried to tuck me under his fin.
It was very, very scary... until I saw the shark.
The whale came right up behind me and pushed me to the boat.
MUSTILL: Suddenly I was drawn into a much bigger story.
I became obsessed with whales, and that's where the detective work starts.
♪♪ ♪♪ WOMAN: Beautiful.
They're surrounding that boat right now.
MUSTILL: In 2015, I was in a kayak whale watching trip in California with my friend Charlotte.
That's us, there.
And then, this happened.
A humpbacked whale breached on top of us.
MAN: I got him, I got him on video.
MUSTILL: My name's Tom Mustill.
KINLOCH: My name's Charlotte.
MUSTILL: I make documentaries.
KINLOCH: I'm an accountant.
MUSTILL: Out of the water came this giant thing, like a big, black thing, and it blocked out the sun.
KINLOCH: Really it was huge, it was like a building.
MUSTILL: And it happened just like... [ Exhales sharply ] ...and that was it.
I felt this huge swoosh and I was cartwheeled around like a doll.
KINLOCH: I had no idea if either of us were going to survive.
MUSTILL: I remember having to swim, and I seen the surface and swimming towards the surface.
KINLOCH: I remember this absolute elation, seeing light when I got above the water, just being so happy to be alive.
Those lovely kayakers came and they rescued us.
♪♪ MUSTILL: A guy came over and he said, "That's never happened before."
And they drained our kayaks and I climbed back in.
So I started to think, "Well, no one's ever going to believe me."
Two days later, this video pops up on the Internet.
Six million views later... MAN: I got him, I got him on video.
MUSTILL: ...I found myself watching it, over and over again.
It's the most ridiculous thing that's ever happened to me and probably will ever happen to me.
How can you get that close to something that big and that much power and not die?
I started to realize that we weren't alone.
There were other videos of other close encounters.
WOMAN: Please tell me you got that, Julie?
[ Screams ] MUSTILL: Charlotte went back to work, but I couldn't let it go.
I just wanted to go back and try and figure out what happened to me.
Who was this whale?
Why was it there?
What was it doing?
Did it do that on purpose?
I became sort of obsessed with whales and that's where the detective work starts.
I've come back to California to try to reconstruct what happened to me on that day three years ago.
This is Moss Landing Harbor in Monterey Bay.
Out there is where the humpback whale landed on us.
I make wildlife films.
But this time it's different, because it's personal.
I'm going to have to learn a lot about whales to understand what happened to me.
The first person I turned to for help was Professor Joy Reidenberg.
Joy has advised me on many films over the years.
She is one of the great experts of whale anatomy.
When a whale dies, Joy dissects it and she's done a lot.
REIDENBERG: Maybe I'm getting close to a thousand.
MUSTILL: These are the tools of her trade.
REIDENBERG: You can't hurt something that's already dead, but you can learn a lot from it.
MUSTILL: I've come to Joy to get a humpback whale 101.
REIDENBERG: A humpback is so much bigger than a person, but it's throat is only a little bit bigger than yours is.
MUSTILL: A humpback hasn't got any teeth.
According to Joy it can't even nibble you, let alone swallow you.
REIDENBERG: They have baleen which is kind of like a big set of brushes in their mouth, and they filter the food through that so the water squirts out and the fish stays.
MUSTILL: They might look very different, but they are our relatives.
REIDENBERG: In many ways they're actually closer to us than many other animals that share the world with us.
MUSTILL: Whales are mammals.
Their ancestors once lived on the land, but then they moved back to the sea.
REIDENBERG: They breathe air like we do, they have pregnancies like we do, give birth to live young, nurse them with milk, maintain a high body temperature.
All these are mammalian things.
MUSTILL: Their skin, just like ours, constantly grows and sheds, feeding armies of giant lice.
REIDENBERG: They're so big even their lice are the size of your thumbnail.
They can host a community of other animals on their bodies, like barnacles.
MUSTILL: Barnacles are shell fish that take root on whales and live there for their whole lives.
REIDENBERG: I actually think they use these barnacles as weapons, like brass knuckles.
MUSTILL: Inside a humpback's pectoral fins are the biggest arms on the planet.
Its big tail fins are called flukes.
They can propel this 30-ton beast into the air in what is known as a breach.
Sometimes they breach close to our boats and extremely rarely, they land on people, like us.
This is the other reason I've come to see Joy.
I want her to look at my breach.
Just have a watch of it.
[ Laughs ] MUSTILL: It's not funny.
[ Chuckles ] REIDENBERG: No, no, actually it's not funny.
The thing that really surprised me when I saw that video, was that whale didn't do what I would think is a normal breach.
This whale tried to accomplish an aerial spin while it was flying through the air.
It looked like it was going to tilt, maybe land on its side, maybe land on the back of its head, but instead rotated very counterintuitively the wrong way.
You guys would have been dead if it had landed with the back of its head on you.
MUSTILL: It was a weird breach, do you think?
REIDENBERG: I think it was very unusual.
MUSTILL: Joy's theory is that our whale turned away from us in mid-air.
But why was it breaching at all?
REIDENBERG: We don't even know what breaches are about.
MUSTILL: You don't know what breaches are about?
REIDENBERG: No, there's lots of theories about what breaches are about, no one really knows for sure, because no one can get inside the head and ask a whale, "Why did you do that thing?"
That's like asking someone who decides to dance down the street, "Why are you dancing on the street?"
Well, maybe you're happy, or maybe you're crazy, or maybe you've got an ant in our shoe.
I think we have so much we need to learn about these animals.
MUSTILL: So it seems that the animal that could've killed me, although a giant, is an enigma.
Here's a short list of what we don't know about humpback whales -- we don't know how long they live, we don't know how many there are, we don't know what their beautiful songs are for.
We've named all the ways they splash -- tail throw... tail slap... chin slap... pec slap... ...breach... but we don't know why they do any of them.
♪♪ Most of our explanations for their behaviors are still theories, because almost all of their lives are hidden beneath the waves.
This is the sea off Moss Landing.
This is where the whale landed on me.
And this is MBARI, it's a marine research center and somewhere I hope I can get some answers.
RYAN: My name is John Ryan.
MUSTILL: He's a scientist here.
RYAN: I'm a guy who listens to whales in the world they live in.
MUSTILL: I've come to ask John why my whale was here.
RYAN: Monterey Bay is spectacular when we view it at the surface and if we were to look beneath the water, we would see that it is spectacular along the bottom, because the bay is bisected by a massive submarine canyon, on the scale of the Grand Canyon, and this means that very deep water is close to shore.
MUSTILL: The scientists at MBARI have explored this canyon and found it stretches over 250 miles and is as much as 12,000 feet deep.
RYAN: Many species of animals are difficult to study with visual methods.
However, they vocalize, which means that just by listening continuously in the ocean, we can learn a lot about their lives.
[ Whale singing ] MUSTILL: This is the call of a male humpback whale.
John's listening to a microphone that he attached to a monitoring station, 3,000 feet beneath the waves.
Down here, MBARI's machines can see and hear what we cannot.
This deep water is rich in nutrients.
And when it rises and hits sunlight, there's a colossal explosion of life, an enormous interconnected feast.
Squid, seals, eels, sea slugs, jellyfish, sharks, otters, mola mola, kelp, sea lions, sea birds in their tens of thousands and of course, whales.
They are drawn to feast on krill and fish.
This is why my whale was here.
Monterey Bay is a humpback feeding ground.
RYAN: We can see whales out this window sometimes, foraging very close to shore.
I love it here.
MUSTILL: But on that day, there was an unprecedented layer of anchovies, 150 feet deep, over a mile long, and packed into the canyon mouth, and we were right on top of it.
But we weren't alone, the whales had come to feed and people had come to see the whales.
This stretch of coast is one of the whale watching centers of the world.
WOMAN: Oh, my God!
[ Cheering ] MUSTILL: This sight would have been unbelievable until recently, because Monterey Bay was once a whaling base.
We hunted whales for their oil, baleen, flesh and bones.
Last century, we killed an estimated 3 million of them, reducing some populations to almost nothing.
Thankfully, here, the slaughter has stopped and the humpbacks seem to be recovering, their numbers roughly tripling in the last 25 years.
Where once we caught whales now we capture their pictures.
Whale watchers are drawn here in their thousands.
I know about humpback whales in general, but I have become intrigued by my whale.
Is there a photo of it somewhere?
Could I even identify who it is?
MUSTILL: I've heard of someone who can help me find out.
CHEESEMAN: I guess people would call me the whale tail guy.
MUSTILL: Ted Cheeseman runs an unparalleled humpback whale photo identification service.
CHEESEMAN: I've now looked at way over 100,000 images of whales.
MUSTILL: Has that made you weird?
CHEESEMAN: [ Laughs ] It could be.
MUSTILL: Ted's database is called Happy Whale and it relies on a very helpful feature of whale's tails.
CHEESEMAN: Humpback whales' tails are really fantastic.
They will tend to scar black on white.
MUSTILL: A humpback's life story is written in the unique pattern of scars on its tail flukes.
CHEESEMAN: You can use the bite marks of killer whales, you can use scars from entanglement in fishing gear, barnacles leave a little round scar.
MUSTILL: For decades, scientists have painstakingly assembled catalogues of humpbacks' tail flukes, which they gave to Ted.
CHEESEMAN: 7,000 images of 3,000 known individuals, over the past 25, 30 years of whale science in California.
MUSTILL: Ted's big idea was to combine these catalogues with a constant stream of whale watching photographs.
WOMAN: Oh, I like that one.
CHEESEMAN: So you see a whale, you take a photograph, send it to Happy Whale.
We'll identify that individual, it might be the whale Grumpy, it might be Frosty, one of my favorites.
MUSTILL: People's holiday snaps have become a scientific tool.
CHEESEMAN: We have identified about 1,500 in the last three years, so that's coming close to, say, 70% of individuals in California.
MUSTILL: Is there a chance we could track down my whale?
Is it somewhere in Ted's archive?
I want to know if it's possible to identify any of the whales?
CHEESEMAN: Hmm, I don't know.
2015 we were just starting, and so... MUSTILL: I'd hoped we could get a lead from the shots of the whales spotted next to us from right before the breach.
CHEESEMAN: It's very odd, but, um... MUSTILL: Do you want to try it?
CHEESEMAN: It's running, I just loaded the -- I took 22 screenshots, so here in I'm attempting to match these against one of our catalogues, which has 18,000 photos in it.
MUSTILL: Do you think you can find it?
CHEESEMAN: I'm not very hopeful.
I mean, we can look at it.
MUSTILL: I had hoped we might be able to identify a few suspects.
But Ted got back to me a few days later, it turns out that September 12, 2015, was a freak day.
More whales were identified that day than almost any other.
He sent me photo after photo of flukes and their catalogue numbers.
In Monterey Bay alone, 51 different known whales were confirmed that day.
How could I ever find out which one is my whale?
♪♪ But a very different question had been bothering me.
Was this an aggressive act?
Could it have jumped on us on purpose?
Despite having hunted them, stories of whales attacking humans are rare, but I had heard of one.
HOWARD: If the animal had hit me eight inches higher, it would have hit me in the neck, it would have knocked my head clean off.
MUSTILL: This is Howard and Michele Hall.
They're a team.
MICHELE: If I'm boss, he's president.
MUSTILL: They are pioneer underwater filmmakers.
MICHELE: Over 3,200 dives.
I have kept track.
MUSTILL: This is a grey whale's penis.
Over 30 years ago, Howard recorded one of the first ever shots of one underwater.
But it almost cost him his life.
HOWARD: I never saw it and I was unconscious when I got that.
[ Laughs ] MUSTILL: We managed to find the film to show him.
HOWARD: This is the first time I've seen it in 20 some-odd years.
I was working for a producer that wanted to capture a shot of whales mating underwater, which is totally impossible.
Um, visibility down there is only about two meters, about six feet.
I took a deep breath, swam down thirty feet and swam out towards some whales that were mating.
And that's when it got scary.
Within a few seconds, I could see dark shapes all around me and that was literally terrifying, to know that you're in the midst of whales that are violently mating.
And suddenly, right in front of me, there was a whale's face, and I could see its eye.
The whole animal just bolted.
I was totally terrified.
I knew I was going to get hit, and I curled up into a ball, trying to make as small a target as possible.
And then the next thing, there was a whale's tail next to my left arm.
I didn't see it coming.
It just happened.
It sounded like a shotgun went off right next to my ear, very, very loud explosion, and then the lights went out.
I was unconscious for 20 seconds or more and when I woke up, I'm upside down, sinking toward the bottom of this murky bay.
I just managed to get to the surface.
I had a broken arm, two broken ribs.
But the good part of the story is that I had the camera running.
Footage of this gigantic, 12-foot-long prehensile penis moving through the frame.
And I wasn't enormously proud of the shot, because it really wasn't composed very well, but that's excusable, considering I was, you know, unconscious.
♪♪ MUSTILL: Howard believes the whale intentionally attacked him, because he got too close and surprised it.
But following this encounter, Howard has continued to film whales underwater, like these humpbacks.
Is he not scared, being so close to these giants?
HOWARD: It's not scary being in the water with whales... ...especially when you consider that an animal that's literally gigantic can so easily hurt you, even unintentionally, and they tend not to.
You get a sense when you're with one of these animals that it recognizes you as another living thing and is looking back at you when you're looking at it, and it is careful not to hit you or hurt you, or be aggressive to you.
MICHELE: It sort of leaves me speechless to try to describe what it's like to see a mom and calf, that allow you to be in their proximity and swim by you, swim around you, move their pectoral fin, where you think, "Oh, my gosh.
It's going to hit me," but it doesn't.
♪♪ MUSTILL: So how come my whale hit me?
MICHELE: This is just so mind-boggling.
Oh, my gosh.
HOWARD: They can make mistakes just like people do.
And I think that animal just, you know, kind of blew it, was jumping, wasn't paying attention and, ah, it wouldn't have done it on purpose, but, you know, you were just in the wrong place at the wrong time.
MUSTILL: Wrong place, wrong time.
It seems what happened to me was just an accident.
My investigation had been into my whale and my experience, but suddenly I was drawn into a much bigger story.
On May the 9th, we heard that a whale had been found dead three hours north of where we were staying.
Joy arrives to join a big team that's gathering.
When dead whales turn up in San Francisco, they're towed to this uninhabited island.
The remains of other dead whales litter the shores.
REIDENBERG: The first priority is, why did this animal die?
If we don't know why it died, we can't do anything about it, we can't stop it.
If we lose those opportunities, then we may lose the species, because we will have missed the warning signs.
The red flags are all there, but we have to find them.
So it's a crime scene first, we got to understand why the whale died.
Once that's established, the next order of business is scientific collection.
This is the saddest part of all, because it's a female and a fairly young female.
MUSTILL: Fin whales are an endangered species.
This young female would have had many years of life and many calves ahead of her.
A big team has gathered to do a thorough necropsy.
It will take many hours in the hot sun to find out what killed her.
Joy has a suspicion that something big hit this whale and she's looking for proof.
REIDENBERG: The layer underneath that muscle should look like this, should be kind of whitish yellow.
This is not normal, That's a bruise.
REIDENBERG: And bruising would indicate that it was bleeding.
And bleeding indicates it was alive when it was struck.
And when you look over here, that's rust from the boat.
MUSTILL: Is it?
REIDENBERG: That is like probably the site of the main impact, right here.
MUSTILL: Joy needs more evidence and the team dig deeper into the whale.
Finally, the team expose the spine.
But it's not all where it should be.
REIDENBERG: But this one's been pushed out of position, so much so that it's up against a rib.
It should be in the middle of the whale, it shouldn't be up against the rib, this is crazy.
That's a massive amount of pressure and it also means that the whale was really snapped in half.
MUSTILL: You just don't think of whales as things that snap.
REIDENBERG: They shouldn't.
REIDENBERG: What would normally hit a whale that hard?
There's nothing bigger than a whale in nature, and then comes along a ship and we just need to know how to handle that.
I don't think this was done purposely.
REIDENBERG: It's, like it's more that I'm sad.
I'm sad that it happens, I'm angry that we haven't been able to do something about it to stop it and the tragedy.
More than anything else, it's a tragedy.
MUSTILL: The necropsy complete, the remains of the whale are left for scavenger, and Joy and the team head home.
♪♪ Sadly, this wasn't the only dead whale I saw that week.
First a gray whale calf was spotted with its mother, with what looked like propeller wounds on its tail.
It washed up on our local beach a few days later.
Then two different humpbacks were seen with fishing gear wrapped around them, like this one, with it's pec fins bound to its sides.
CHEESEMAN: We see a lot of scarring of whales running into human stuff.
More than half the whales probably bear some kind of scarring from a ship strike, or from an entanglement.
MUSTILL: I learned that whales have been turning up entangled, injured or dead, in record numbers.
The last five years had seen a 300% increase in humpback entanglements alone.
On the east coast, so many humpbacks were dying that a UME had been declared.
What's a UME?
REIDENBERG: UME is the abbreviation for Unusual Mortality Event, which simply means that we're getting too many dead animals and we don't know why that's happening.
It's really like declaring a state of emergency for whales.
We have to take stock of what's happening and really understand this, so that we can stop it.
MUSTILL: I started out wondering if my whale had tried to kill me, but now all I can think of is have we somehow killed it?
Do you think people would be upset?
CHEESEMAN: Oh, not upset, people would be up in arms.
You're driving down the road, you see a deer caught in a fence, right, you wouldn't just drive by, at the very least you'd call 911.
But these whales are out of sight, out of mind.
MUSTILL: But all hope is not lost.
There are highly trained volunteers standing by along the whole west coast waiting for word that a whale is in trouble.
FOLKENS: We as human beings owe it to these innocent animals to reduce their suffering and save their lives.
MUSTILL: This is Pieter.
FOLKENS: My name is Pieter Arend Folkens.
I'm one of a small group of individuals that disentangles whales.
MUSTILL: Just a handful of people in the state are authorized to cut trapped whales free.
It's August the 8th.
Fishermen had found a whale in trouble.
We joined a team of three small boats and a coast guard escort, heading out into the open sea.
No crew has ever filmed a disentanglement here before.
It took us hours to reach the whale.
The whale is trapped by a rope, attached to fishing gear on the sea bed.
The team thinks it could have been like this for weeks.
Approaching the whale now, Tim.
FOLKENS: Try to get behind where the float is, if you can.
♪♪ There are few things that I've ever done that are as dangerous as disentangling whales.
You don't know what this animal's thinking and feeling, and it may lash out at you.
You know the animal's scared, it's frightened, it might think of you as a threat and is going to defend itself against the threat.
People have been killed disentangling whales, I know three just in the last few decades.
And so we absolutely insist that nobody even attempt it if they don't have a thorough understanding of what they're doing.
MAN: I think we're deep enough, I'm going to pull in.
FOLKENS: Okay, we might get a reaction out of the animal.
MUSTILL: The rope has cut deep into the whale.
FOLKENS: Okay, that was a stress blow.
We're out there being very sensitive to the scared animal, listening to its blows, ah, are they stressful or are they relaxed?
WOMAN: That was a blow.
FOLKENS: Stress blow.
Yeah, he knows that we're here.
Be mindful of the flukes.
MAN: Hey, Pieter, it's underneath like a jumble in the body of the whale.
FOLKENS: Okay, then what you can do is you can drop it.
MAN: Just drop it.
FOLKENS: Drop it.
WOMAN: Drop it on the right side.
FOLKENS: Drop it on the right side of the whale.
It's a very anxious period of time and it's not comfortable.
MAN: Dropping on one side.
MAN #2: Flukes are underneath the bough.
MAN #3: Hold them up.
MAN #2: Okay, we're above the flukes right now.
MUSTILL: With the weather turning, the team is running out of time.
But Pieter judges that the whale is relaxed enough to move in for the cut.
FOLKENS: Do you have your safety knife?
MUSTILL: At this point, Pieter is attached by a rope to an animal larger than a T-Rex, just feet from its biggest weapon, its tail.
Pieter makes the cut.
FOLKENS: If it dives the floatation, we'll pull it through.
MUSTILL: As the whale swims away, the rope pulls out of its tail.
MAN: It's pulling through now.
FOLKENS: Almost there, almost there.
MUSTILL: And after weeks joined to the sea floor, it's free.
MAN: ...the whale, the whale is now free.
MAN #2: Free.
FOLKENS: It's like a huge emotional rush that we accomplished the task, everybody's safe.
And I don't have to worry about it anymore.
Although the animal's tail has been deeply compromised, there's at least a chance in there that it will now survive.
It was kind of a release, the adrenaline's flowing away, realizing that we had done something that was, without question, good.
MUSTILL: There's one animal I can't stop thinking about -- my whale.
What happened to it, in this ocean that I now know is so dangerous for its kind?
I need to narrow down this wall of tails to one whale.
I figured out that there were three boats on the water near us that fateful morning.
In the first one, the captain, Mike, managed to get photos of the whale while it landed on our kayak, but crucially, its tail is underwater.
His camera metadata shows the whale landed on us at 9:24 AM.
Next was Captain Kate Spencer.
When we were in the water, her boat raced over.
Her GPS track shows exactly where we were.
On the third boat was Captain Kate Cummings.
She missed our breach, but photographed other breaching whales that day.
Could one of these be our whale breaching again?
And a final witness was watching from afar.
Filming from the beach that day was a woman called Debi Tomkins.
Debi is obsessed with whales.
TOMKINS: That was after I saw my first blue whale.
TOMKINS: I love whales.
MUSTILL: She wears them on her skin and ears.
In an astonishing fluke, Debi had unknowingly captured a second angle of the most extraordinary moment of my life.
TOMKINS: I got him him splashing!
Have you talked to them at all?
TOMKINS: The people that it happened to?
MUSTILL: It was me.
TOMKINS: You're [bleep]!
I didn't know that!
MUSTILL: I thought you'd figured it out.
[ Laughs ] Can't imagine what that was like.
MUSTILL: Not one of these witnesses had got a shot of our whale's tail.
But now I had a precise time and place, two videos and scores of photos.
Was my whale's identity somewhere in all of this?
I'd been sent some videos from my new friends, the whale watchers, ones without an easy explanation... MAN: Wow.
MUSTILL: ...where the whales almost seem to be watching the whale watchers.
Just look at them go CHEESEMAN: Here we have the leviathan, the giants of the deep, which turn out to be friendly animals.
CHEESEMAN: They're curious about us, they turn out to not be out to kill us, even though we spent centuries very successfully killing them.
WOMAN: Wow... MUSTILL: Could humpbacks be interested in other species?
I'd seen another video, viewed over 10 million times, stranger than all the rest.
HAUSER: Seriously, I would never believe any of this, as a biologist and a researcher, I would -- unless it happened to me, because I just can't believe it happened to me.
But if someone told me this story, I never would believe it.
MUSTILL: This is Nan.
HAUSER: Nan Hauser.
MUSTILL: Nan has spent much of her life studying whales in the Cook Islands.
HAUSER: I was famous for getting the first sperm whale fart and... MUSTILL: The first fart?
HAUSER: Yes, the first sperm whale fart.
MUSTILL: Here's the fart in one of Joy's scientific papers.
Recently, Nan had an encounter stranger than any other I'd heard of.
HAUSER: I just knew that it was a dangerous situation.
MUSTILL: Humpbacks normally avoid touching people and Nan would never normally touch a whale, but here she felt she had no choice.
HAUSER: I couldn't push 50,000 pounds away from me, but I knew that I could push me away from 50,000 pounds.
It tried to tuck me under his fin and literally would swim until I could be under his fin and I'd hold on to it, so that he couldn't hold me there, because I would drown.
And his eye was right next to mine, he had this eye widening where you see the whites of his eye.
It was painful and it was very, very scary.
This went on for 10 and a half minutes... ...until I saw the shark.
The whale came right up behind me and pushed me to the boat.
There's a big, big tiger shark up there.
WOMAN: Well, come on the boat.
MAN: Got a big tiger shark.
HAUSER: And climbing up on the back of the boat and the whale was still there.
WOMAN: Um, Nan, the whale.
[ Whale blows ] HAUSER: I love you, too.
I love you, too.
This is not a normal thing.
I love you.
I just know that it's incredible, altruistic behavior.
MUSTILL: What's altruistic behavior?
HAUSER: Altruism is when you commit an act to help or protect another life without expecting anything in return.
What did this whale gain from any of this, other than pushing me to the boat and protecting me?
MUSTILL: It turns out that Nan isn't the only one to have been saved by a humpback.
There have been over 100 recorded incidents of humpbacks interfering when other species are being hunted.
The global center of these is Monterey Bay, and this woman has been seeing it for years.
BLACK: Humpbacks are saving other animals.
Why are they doing this?
MUSTILL: Meet Nancy.
BLACK: My name is Nancy Black.
MUSTILL: The animal Nancy loves the most is the killer whale.
BLACK: I just, like, saw them and I'm like, "I just want to study wild killer whales."
MUSTILL: Nancy has spent her life following them and named her boats after them.
BLACK: The Sea Wolf, the other boat is called the Blackfin.
MUSTILL: She's one of the great pioneers of whale watching in Monterey Bay.
BLACK: When I first started, way back in the late '80s, no one believed me that there was whales here to watch.
MUSTILL: This is Jason, and this is Mike.
They're Nancy's drone guides, giving her a new perspective on whale behavior.
BLACK: You can see things from the air that you wouldn't see at all from the boat.
MUSTILL: This season, Nancy watched from above as killer whales hunted and killed this gray whale calf.
And then from nowhere, humpbacks arrived.
Humpbacks are the killer whales' mortal enemies.
What were they doing so close together?
I was on the surface and could only catch glimpses of what was happening.
There's just sort of humpbacks everywhere and then killer whales everywhere and trying to figure out what, with all the boats, what's happening must be really difficult.
From above, Nancy could see the whole scene.
BLACK: With the drone, you can see where the humpbacks are in relation to the killer whales.
MUSTILL: What were they doing?
BLACK: They were protecting the carcass from the killer whales from coming.
It's almost like they're acting like it was their own calf.
MUSTILL: The carcass has been pushed deeper underwater and the humpbacks seem to be chasing the killer whales away and throwing their tails.
A blow from a humpback could kill a killer whale.
Do you just think they hate killer whales?
BLACK: [ Chuckles ] Probably, yeah.
Whatever it is, their instinct is to shoo them away.
MUSTILL: Humpbacks have been seen coming to the rescue of seals, sea lions, dolphins and even giant ocean sun fish.
REIDENBERG: Are they really that altruistic?
Do they really care about saving other animals?
I don't want to think it initially, as a scientist, because I feel like I'm anthropomorphizing the whale.
But when you see more and more and more evidence of these animals saving other animals, then you have to start thinking, is their social awareness of other species so high that they feel empathy to other animals, that they want to save those animals?
BLACK: Other baleen whales, like blue whales and fin whales, are very scared of killer whales.
MUSTILL: Where the biggest animal on the planet, the blue whale flees... humpbacks can fight.
No other whale has such giant and lumpy pectoral fins.
Scientists think that these 16-foot-long deadly weapons give humpbacks the power to take on the wolves of the sea.
♪♪ It was our humpbacks pectoral fin that hit our kayak and crucially, from the beach, Debi had filmed a clear shot of that fin, so I took it to show Ted.
There, that is pretty good.
CHEESEMAN: Oh, that is pretty good.
Okay, so... MUSTILL: Ted found a breaching whale from that day with a similar pec fin.
CHEESEMAN: These are Kate Spencer's photos.
This is your day, but this is at -- this is an hour and 20 minutes later.
Let's zoom in a little bit, take a little screenshot of it, so we have a reference there and then let's go to this video.
MUSTILL: It's got a dark lump there.
MUSTILL: It's got a shape there, got a white gap running through there, then it's got a dark lump there.
CHEESEMAN: That makes this an interesting suspect.
MUSTILL: Could you look at all of the photos of our candidate?
MUSTILL: Poor sea lions.
CHEESEMAN: They're just having a ball.
MUSTILL: Wait, that's, that's us.
CHEESEMAN: There you go.
MUSTILL: Wait, that's next to us.
One of these boats is, is our boat.
She is in our kayak group.
That's her there.
I think that makes it the prime suspect.
It's got the same left underarm pec.
MUSTILL: Well, not the same, but very -- Who knows?
It doesn't look dissimilar.
CHEESEMAN: Yep, exactly.
MUSTILL: It's next to us just before we get breached on and it's breaching after we get breached on.
CHEESEMAN: It's a strong case.
CHEESEMAN: In your honor, Tom... MUSTILL: You're going to...?
[ Laughs ] CHEESEMAN: ...we're going to name this whale Prime Suspect.
[ Laughs ] I like it.
MUSTILL: I didn't think that would work.
I didn't think it would work.
What's that line there?
CHEESEMAN: Ah, we could ask Pieter.
MUSTILL: Pieter looked at the scars on the whale we'd named Prime Suspect.
FOLKENS: See that little indentation right there?
That's very typical of an entanglement.
MUSTILL: Prime Suspect, like over half the whales in these waters, bare scars from contact with us.
And Pieter also picked up on something else, something I'd missed, even though I'd watched the video hundreds of times.
FOLKENS: There is a lot of awareness going on here, 'cause usually those eyes are much closer in on the body to kind of protect them and they're looking to the sides, but this animal has pushed them out.
Look at the eyes here.
The eyes are now distended out.
It's looking down at the kayak.
Eyes in, starts to go out, goes out more, goes out more.
MUSTILL: So now I know that as I looked up at Prime Suspect, it stuck out its eyes and looked back down on us.
And finally, Peter wanted to check that we'd got the right whale.
Humpback whales have knobs on their faces.
These have whiskers inside them and their patterns are unique to each whale.
♪♪ ♪♪ FOLKENS: Here it is.
Okay, that's what I'm looking for.
So you got your blowhole here, you got your blowhole there.
Just on the opposite side of the blowhole, you see these paired rostral knobs, smaller/bigger, smaller/bigger.
So based on this photograph and that frame from the video, these are the same animals.
That's my story and I'm sticking to it.
MUSTILL: So Debi's video of our breacher gave us a glimpse of its left pec fin, which looked like the left pec fin of a whale Kate Spencer saw breaching an hour later.
That same whale was photographed by Kate Cummings, next to some kayakers just before the breach, the same people who came to our rescue minutes later.
From Pieter came the final piece of evidence -- the knobs on my whale's head are a perfect match.
Against the odds, we've solved this whale whodunnit.
But this success is bittersweet.
Prime Suspect has become an individual to me and somehow more real, and I want this whale to be okay.
But I still don't know where it is.
I want to meet someone who can tell me what the future holds for Prime Suspect and its fellow whales.
FRIEDLAENDER: I think there's a real chance that there's a couple of species or populations of whales that could go extinct in my lifetime if we don't do things differently.
And I take that personally, I take responsibility for that at some level, because I'm a human and I don't like it.
MUSTILL: This is Ari.
FRIEDLAENDER: My name is Ari Friedlaender... MUSTILL: And this is Ari's job.
FRIEDLAENDER: ...the guy that puts tags on whales and learns about what they do.
MUSTILL: Ari is one of the pioneers of whale tagging.
The tags don't hurt the whales and they can stay in place for hours.
They can record the direction the whale moves, how fast and how deep and most vividly of all, videos pointing in different directions from the whale.
They are a powerful new conservation weapon.
FRIEDLAENDER: Every tag we get back and watch is new and we learn things every minute of every tag that we've ever put out.
MUSTILL: What's the feeling that you get when you just watch hour after hour of being a whale?
FRIEDLAENDER: Ah, man, we don't know anything, you know?
Like, you're constantly seeing things that you had no idea they did or that you didn't expect to see.
You're humbled, for sure.
♪♪ MUSTILL: This is how our distant cousins live, in a world where we cannot go and haven't seen before.
FRIEDLAENDER: It's ballet underwater, it's calming, it's so quiet, just unbelievable.
MUSTILL: We can see a humpback use its mighty tail to propel itself into a breach.
♪♪ We can watch them swoop through schools of fish... ...and see them swimming among the other animals.
We see that humpbacks, despite their size, are far more agile than we suspected and maneuver gracefully around one another.
But sometimes, like this, they bump into each other.
♪♪ ♪♪ These are tiny and profound glimpses into what it's like to be a whale, and they are vital.
FRIEDLAENDER: I often have these guilty feelings like am I doing enough?
Are we getting enough out of this?
Are we doing enough for these animals, just with our science?
MUSTILL: This year, Ari and his team are combining tagging with a massive interdisciplinary whale science blitz.
For two weeks, along with scores of scientists from different universities and research centers, they're throwing everything they're got at understanding the whales here.
Biopsy darts take DNA samples.
MAN: Good sample.
MUSTILL: From the big boats, they take noise recordings, plastic trawls, fish scans and catch samples of whale feces.
MAN: All the things we do for science.
We can tell all kind of cool stuff from stuff, like how stressed out they are, you can look at their hormones.
MUSTILL: The hope is that by building the most complete picture yet of the whales and their environment, we can find a way to share the sea.
FRIEDLAENDER: It's not up to a whale to not get entangled, or to get struck by a ship.
It's up to us to slow that ship down, to put it in a different place, or to use lines or types of fishing gear that aren't going to lethally, you know, take down that animal.
MUSTILL: But people won't change unless they care.
♪♪ FRIEDLAENDER: I'd love for people to be able to feel what I do and to have that kind of connection to these animals.
♪♪ I want to find out how these animals live and I want to use that information to make people care more.
MUSTILL: A member of this giant team is someone I've been wanting to see for a while, a legend in this community.
When he started, over 30 years ago, few had studied the whales here.
He now has the largest whale database on the entire west coast.
I wanted to ask him about my whale.
CALAMBOKIDIS: Prime Suspect is one of the whales that we've regularly seen on the California coast, going back to 2008 -- an animal that was actually first identified as a calf and we actually knew who its mother was.
MUSTILL: This is Prime Suspect's mum, and this is Prime Suspect as a calf, when its tail flukes were still white.
So you know who it -- when it was born and who its mum is?
We try to track, I mean it's in our database.
We take this for granted, you know, among these 36,000 records we have.
We know from where it's been seen that it has a high chance, both it and its mother, of being an animal that either came from mainland Mexico or Central America.
MUSTILL: When was it born?
How old is it?
CALAMBOKIDIS: Ah, seven years old in 2015.
MUSTILL: I mean, that's amazing.
Ah, no, it's kind of neat that we know that about it.
MUSTILL: Now I know what happened that day.
That morning, we paddled out over a giant underwater canyon and into one of the greatest concentrations of humpbacks in this coast's history.
The humpbacks were just doing what humpbacks do.
I don't think it was trying to hit us.
I know it was seven years old, that it first came with its mother from Central America, that it has returned each year since then until now.
I know it has survived being entangled.
But for all I've learned, I do not know where Prime Suspect is today.
As my time drew to an end, Charlotte joined me and I told her everything.
We went out every day, our eyes always peeled for a particular whale.
KINLOCH: I would love Prime Suspect to have a long and happy life.
Hopefully we'll see it before I go home, that would be amazing.
MUSTILL: It was our last day out, but when we left Moss Landing, there wasn't a whale to be seen.
All of the other boats had driven far away in search of whales.
And then this happened.
MUSTILL: It's right in front of us.
♪♪ KINLOCH: Whoo!
[ Laughs ] ♪♪ ♪♪ MUSTILL: Again and again the lone whale kept going, breaching, chin slapping, pec slapping, tail throwing.
It doesn't get better than this.
♪♪ ♪♪ ♪♪ MAN: That was amazing.
We just had an incredible chronic breaching humpback whale.
MUSTILL: You call them chronic breaches?
MAN: Chronic, they keep going, they don't stop.
At least over 30 times.
MUSTILL: Now we can add our video to the ever expanding library of whale awesomeness.
This is the closest I can bring you to the moment frozen in my mind -- a whale suspended in the air... ...the most spectacular thing, I think, in the world.
But this whale was not Prime Suspect.
Its name is 0501280, and it was time for me to go home.
This detective story started as a whodunnit, which I never expected to solve.
It's led me into a much bigger story of a unique community, driven by their passion to understand, protect and take wonder in whales.
They've taught me how much, and yet how little we know about these colossal animals.
Without them, the whales here would be in trouble.
And with their help, the search for Prime Suspect can continue.
And will you keep an eye out for me?
CALAMBOKIDIS: Ah, yes, but I have about 3,500 other humpbacks I'm keeping an eye out for, so I might get it confused.
[ Laughs ] ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.