[RADIOLAB INTRO]

LATIF NASSER: Hey, I'm Latif Nasser. This is Radiolab. Day four of our week of sharks.

ALISON KOCK: Hello?

RACHAEL CUSICK: Hello!

LATIF: And we're starting today with our shark guide in residence, Rachael Cusick and this lady.

ALISON KOCK: I'm Alison Kock. I'm a marine biologist.

LATIF: In South Africa. At a car wash.

ALISON KOCK: Oh my gosh, yes.

RACHAEL: [laughs]

RACHAEL: Today, Alison works for South Africa's national parks, but back in the '90s—young, without a lot of money ...

ALISON KOCK: I was a student at the University of Cape Town, working at that car wash that you mentioned.

RACHAEL: It was a small little spot, not one of those drive-through car washes with those, like, flying sponges.

ALISON KOCK: It was all by—yeah, by hand. And my role was to check the cars for valuables, and move the cars from the wash basin through to the dry basin. I used to also love just being around water, so that was another draw card for the car wash. [laughs]

RACHAEL: Wow, you're like, "I'll even take the soapy water of a car wash, even if it's not the ocean."

ALISON KOCK: Absolutely. If it's close to water and ...

RACHAEL: One day, you know, Alison's doing her thing—wash, rinse, repeat—when one car, it kind of changed her life, this car.

LATIF: Where is this going? How could a car at a car wash change someone's life? Okay, keep going.

RACHAEL: So she gets—she, like, kind of checks the front for front valuables. Nothing there. Nothing in the back seat. But she then goes to the trunk.

LATIF: Dead body in the trunk.

RACHAEL: Dead body in the trunk. Exactly. [laughs] And she opens up this trunk, and inside the trunk are these photographs.

ALISON KOCK: It just blew me away.

RACHAEL: There, in full color, is this—is this image of a shark.

ALISON KOCK: This incredibly big, massive, great white shark.

RACHAEL: Soaring above the waves below.

ALISON KOCK: Completely out of the water, flying fully in the air like an airplane.

RACHAEL: It was unlike anything she'd ever seen.

ALISON KOCK: Absolutely. But I was quite skeptical.

RACHAEL: Like, you thought they were photoshopped or something?

ALISON KOCK: Well, at the time, Photoshop wasn't—I just, I thought they were fake, you know? I just—I couldn't believe that I'd spent three years at university studying marine biology, and not one time did anybody mention flying great white sharks.

RACHAEL: And so, you know, when the car owner returned to get his car, Alison asked him, like, "What is this photo? Is this fake?"

ALISON KOCK: And he said it's real, that a friend of his takes these photographs. And I just said to him, "Look, this car wash will be on me if you introduce me to your friend." And a few weeks later ...

RACHAEL: Alison is on a boat with that friend.

ALISON KOCK: Chris Fallows.

RACHAEL: And also one of his friends, a guy named Rob.

LATIF: And was there any part of her that was like, "They photoshopped this image and now they're kidnapping me?"

RACHAEL: Well, that's what I was saying.

RACHAEL: Like, very trusting of you to believe these men and go out on their boat.

ALISON KOCK: [laughs] Looking back, it probably was. Yeah.

RACHAEL: Anyhow ...

ALISON KOCK: I mean, it was a beautiful day. It was a flat day, and there was very little wind.

RACHAEL: The sun hadn't risen yet; the sky was totally black. They were headed out to a place called Seal Island.

ALISON KOCK: About a 25-minute boat trip.

RACHAEL: This massive breeding colony of seals. And as they're getting closer, she starts hearing the sounds of 60,000 seals.

ALISON KOCK: You just listen to the seals, and you listen to the ocean and the seabirds. But ...

RACHAEL: No sharks.

ALISON KOCK: So, you know, Chris kept saying to me, "Keep your eyes peeled." And him and Rob were really vigilant, and they're staring and they're looking. And the whole time I still was not believing it. You know, I was—still remained very, very skeptical.

RACHAEL: When suddenly ...

ALISON KOCK: Chris shouts, "Predation!" And right in front of my eyes ...

RACHAEL: Where this little, helpless seal is floating ...

ALISON KOCK: ... literally within 10 meters.

RACHAEL: The water seems to, like, open up as this giant, giant shark ...

ALISON KOCK: This incredible animal.

RACHAEL: ... comes flying out from below in the sky. And time kind of, like, slows down at this point for her. Like ...

ALISON KOCK: I'm—I'm in shock.

RACHAEL: Her eyes bulge out of her face, and it's just like this massive shark suspended in air. It's, like, defying every—not just gravity, it's, like, defying every version of any shark that she's ever seen, thought about or learned about in her entire life. It's just like, right in front of her.

ALISON KOCK: There was no fear. I don't know if it was ignorance. [laughs] I felt awe. I just saw majesty. I just saw this incredible beauty.

RACHAEL: And then ...

ALISON KOCK: The shark lands back in the water, actually moving the boat with the wave from the big splash. And I'm still standing there in complete awe. And I just went, "Okay, this is me for the rest of my life. I'm gonna study these sharks."

RACHAEL: And that's exactly what she did. She went back to school, got her Master's, then her PhD, and started making more and more trips out there. And what she quickly discovered was while this is an awesome thing to watch as a human being on a boat ...

NEIL HAMMERSCHLAG: One of the days, I saw 42 great white attacks.

RACHAEL: No way!

NEIL HAMMERSCHLAG: Yeah.

RACHAEL: If you were a seal on Seal Island, this place was terrible.

NEIL HAMMERSCHLAG: I've seen great whites, like, flying out of the water with this seal in its mouth, and the seal is kind of like never giving up.

RACHAEL: Until—crunch!

NEIL HAMMERSCHLAG: And I mean, you're just screaming when you see it happen.

RACHAEL: That, by the way, is Neil.

NEIL HAMMERSCHLAG: Dr. Neil Hammerschlag.

RACHAEL: He's a marine ecologist and a shark researcher. He was spending a ton of time out there, just like Alison.

NEIL HAMMERSCHLAG: If you saw, like, a lone seal coming back to the island, and they're a small kind of baby seal, which would have, you know, smaller claws and not as experienced, like, you would watch it and pull out your camera. I know it sounds terrible, but, like, you could ...

RACHAEL: [laughs]

NEIL HAMMERSCHLAG: ... you'd be sure a great white would come flying out of the water with this seal in its mouth, like, minutes later.

RACHAEL: And Neil started to wonder, like, do these seals register how awful this place is to be a seal? Like, do they feel the fear that I can just see so clearly?

NEIL HAMMERSCHLAG: So I designed this study where we'd actually go to the island, get up on the island and collect seal poop.

RACHAEL: He did the same exact thing on other islands.

NEIL HAMMERSCHLAG: Islands where there weren't sharks. Then analyzed the seal poop for stress levels, stress hormone levels.

RACHAEL: And what, like, cortisol? What were you doing?

NEIL HAMMERSCHLAG: Cortisol. Yeah. Like, metabolized cortisol.

RACHAEL: And what he found was that the seals that live on Seal Island have stress levels that are four times higher than the seals on all the other islands.

LATIF: Wow!

NEIL HAMMERSCHLAG: Yeah. Like, quadruple levels of stress.

RACHAEL: And Neil says you can kind of just see this with the naked eye.

NEIL HAMMERSCHLAG: Yeah. I mean, in the shallow water the sharks couldn't really ambush them, so the seals would always stay within five meters of the island. It seemed like the sharks were controlling their behaviors through just a landscape of fear. They were causing these seals to not go and do whatever they want or hang out wherever they want or behave any way that they wanted. They were keeping them under—under control.

RACHAEL: The way that we imagine sharks, the way that we see them in movies ...

[ARCHIVE CLIP, Sky Sharks: Sharks, but they can fly.]

RACHAEL: ... like, that is what they were ...

[ARCHIVE CLIP: Something's following us.]

[ARCHIVE CLIP, Bait: I can make it! I can make it!]

RACHAEL: ... to the seals on Seal Island.

[ARCHIVE CLIP, Ghost Shark: They've tasted human flesh!]

RACHAEL: However ...

[ARCHIVE CLIP, Deep Blue Sea: Now you've seen how bad things can get and how quick they can get that way. Well, they can get a whole lot worse.]

RACHAEL: For the seals and the sharks of Seal Island, all of that was about to get flipped on its head.

[ARCHIVE CLIP, Deep Blue Sea: And we're gonna find a way to get out of here!]

RACHAEL: And we'll get to that ...

[ARCHIVE CLIP, Deep Blue Sea: First we're gonna seal off this ...]

RACHAEL: ... right after a break.

LATIF: Hey, I'm Latif Nasser. This is Radiolab. We are back with part two of day four of our week of sharks.

RACHAEL: Yay! Okay.

LATIF: Before the break, Rachael, you told us about some high-flying great white sharks, these colossal apex predators terrorizing some poor little seals on an island off the coast of South Africa.

RACHAEL: Yep, that's right. And we are gonna get back to those great whites and those little seals in just a minute. But first, you know, there are other fish in the sea.

ALISON KOCK: We'd been monitoring, so ...

RACHAEL: Back in 2015, Alison Kock, that shark researcher who got her start because of a photograph she had seen, she received another photo of another kind of shark in the bay. But this one, it was different.

ALISON KOCK: Absolutely. Divers sent me photographs of these dead sevengill sharks lying at the bottom of the ocean.

RACHAEL: These sevengill sharks, they are smaller than their great white cousins—a little narrower. But what struck Alison, was that on each of the sharks ...

ALISON KOCK: There was this huge gaping wound, like the shark had literally been cut and sliced open.

RACHAEL: And the slice was so clean, it almost looked like a surgical wound.

ALISON KOCK: I mean, it was such a clean wound that my immediate suspicion was people that had did it.

LATIF: Yeah. Hmm.

RACHAEL: I know.

ALISON KOCK: And that's kind of where we had to leave it because all we had was photographs.

RACHAEL: But then just a couple of months later, another dead sevengill shark was found by a different diver. And so she's like ...

ALISON KOCK: "Please collect it. Please collect it."

RACHAEL: She wants to do, like, Law and Order Shark VU.

LATIF: Yeah, Shark VU. [laughs]

RACHAEL: So anyway ...

ALISON KOCK: They collected it for me. And we did the necropsy at the—at the dive shop, and ...

RACHAEL: As she's poking around at it, she realizes ...

ALISON KOCK: Again, it was ...

RACHAEL: It has the exact same wound as the last one did.

ALISON KOCK: This clean wound between the pectoral fins of the shark.

LATIF: Hmm!

RACHAEL: And that weirdly ...

ALISON KOCK: On closer inspection, the liver was gone.

RACHAEL: The liver had been taken out.

ALISON KOCK: Just the liver.

LATIF: It's, like, creepy, like, Hannibal serial killer vibes.

RACHAEL: Yeah. Or maybe, like, maybe poaching or some shady black market stuff.

ALISON KOCK: Yeah, I didn't know.

RACHAEL: But it doesn't end there. And here is where those great whites on Seal Island spin back into the story. In 2017, Alison gets a call from another Alison, who's another researcher who studies sharks down kind of like the coast of South Africa. And she's like, "Alison, there's this massive great white shark that's washed ashore." And guess exactly what it looks like, Latif.

LATIF: It's got the same slash.

RACHAEL: The slash down the body, liver is missing.

ALISON KOCK: Everything looked exactly the same.

LATIF: Very weird!

RACHAEL: I know! And it's about to get even weirder, because right around the time Alison hears about this one sliced open great white ...

NEIL HAMMERSCHLAG: The sharks at Seal Island literally disappeared.

RACHAEL: Again, Neil Hammerschlag.

NEIL HAMMERSCHLAG: Like they were gone.

ALISON KOCK: So again, I was like, "Gosh, you know, what—what could this be? What's going on?"

RACHAEL: And finally, on the 16th of May, 2022, Alison gets her answer.

ALISON KOCK: So we were contacted by a drone pilot, and he captured the most extraordinary footage.

RACHAEL: There is no sound, but the video starts with this big, wide shot, looking straight down into this blueish-green ocean maybe, like, 50 feet below. And right in the center of the frame, you see this shark and this giant, giant white-spotted black orca. For a while, the pair is just eyeing each other, swimming in these tighter and tighter circles, around and around, until slyly, a second orca swims into the right of the frame.

ALISON KOCK: And the white shark can only keep its eye on one orca at a time.

RACHAEL: The second orca starts to slowly glide towards them, until suddenly, it darts, slamming the shark, rendering it motionless, turning the water frothy white. A moment later as the froth fades, the orca swims next to the motionless shark, this time baring its teeth, it slices out the shark's liver.

LATIF: Oh!

RACHAEL: Before the clip ends, you can actually even see the orcas start feasting on this white, fleshy pouch. And the shark slowly starts to sink, fading into the blue depths of the ocean.

ALISON KOCK: This was unbelievable. Unbelievable!

LATIF: Okay, so it's—so it's the orcas who are killing the sharks?

RACHAEL: Yeah. So yeah, so these—these livers of sharks, they're super nutrient-rich, they're really fatty. They actually take up, like, a third of the shark's body, and so they are, like, the créme de la créme for these orcas. They—they are just this massive meal for them.

LATIF: Right.

RACHAEL: So they go in and they take the—they take the liver, and then they actually just leave.

LATIF: Huh!

RACHAEL: Yeah. I mean, even Alison found this hard to believe.

ALISON KOCK: I was in denial for a very long time. [laughs] Because for me, white sharks were always the apex predator.

LATIF: Oh, wow. Okay. So we're saying the orcas killed all the great whites at Seal Island?

RACHAEL: Well, it seems like they definitely killed some of them. And Neil is quick to point out that we humans killed some of them as well.

NEIL HAMMERSCHLAG: The nets, right? The lethal netting program.

RACHAEL: The government has had nets in the water to protect swimmers. And something like 30 sharks get caught in these nets and killed every year, which is a lot for great white shark populations. So that's definitely a part of their decline. Alison would agree. But here is where things get even more shocking for our apex shark predators: Alison says that for the orcas to clear all the great white sharks out of Seal Island, the orcas didn't need to kill all of them.

ALISON KOCK: No. This is the whole point.

RACHAEL: Alison and her grad students and some researchers in the area, they had tagged a bunch of these sharks. And when they looked at that tagging data, they found ...

ALISON KOCK: That after each predation event ...

RACHAEL: You know, each orca attack ...

ALISON KOCK: It took the sharks longer to come back and fewer came back, until eventually, after about four or five of these predation events that we knew of, the white sharks stayed away and didn't come back. And so, you know, it's very possible that the fear of predation, the fear of being predated on made the white sharks abandon Seal Island.

LATIF: But, like, I can imagine an individual shark getting attacked and then leaving, or even, like, if it sees a friend or family member or something getting attacked and then they leave as, like, a little family unit. But, like, it's not like they have a giant, like, WhatsApp group or something, where they can, like—they're all gonna, you know, leave en masse. Like, how does that even work?

RACHAEL: [laughs] Like a community watch program but for sharks?

LATIF: Yeah.

RACHAEL: [laughs]

LATIF: Yeah.

RACHAEL: Well actually, they kind of do. Like, they have—they have this very cool trick.

CULUM BROWN: I mean, sharks aren't stupid. Fear can spread through a population in much the same way as it can through, you know, a group of people.

RACHAEL: I spoke to this man named Culum Brown. He's the head of this fish lab at Macquarie University in Australia.

RACHAEL: I think one interview called you Dr. Fish Feels or something.

CULUM BROWN: [laughs] Yes, I speak for the fish.

RACHAEL: And he explained to me how fear can spread literally through the water.

CULUM BROWN: So if a shark is injured or killed ...

RACHAEL: It releases this chemical.

CULUM BROWN: A very particular chemical, which in the German word is called "schreckstoff," which literally translates to "scary stuff."

RACHAEL: Signaling, like, something bad is happening here. Go protect yourself. Like, get away.

LATIF: Whoa!

RACHAEL: And if a situation is bad enough ...

CULUM BROWN: Schreckstoff can set off a contagion, effectively. A behavioral contagion. And an entire population could potentially develop a fear response.

RACHAEL: Almost like a scream, echoing through a crowd. Like, it's funny to me that, like, they are—they're, like, poster child for scary, especially these flying white sharks. And yet when you get to know them, they are just these little—these little fish that are scared of bigger fish. That, like, as Culum says, there is always something scarier.

CULUM BROWN: Yeah, there's always a bigger fish in the sea, right? [laughs] And that is virtually true of every animal. The more we find out about fishes and sharks and these sorts of aquatic animals, the more we realize we're basically fish with some tweaks. Of course, we've come quite some way, but nonetheless, our physiology and our sort of behavioral responses haven't really changed that much.

RACHAEL: So next time you're afraid of a shark, just remember they have feelings, too.

LATIF: This episode was reported by Rachael Cusick and produced by Rachael Cusick, Simon Adler and Maria Paz Gutiérrez, with production help from Becky Laks. It was edited by Pat Walters and fact-checked by Diane Kelly, with mixing help and sound design by Jeremy Bloom. And special thanks to Katy Ayres.

LATIF: One more thing: we want to give a big thanks to everyone out there who is a member of The Lab, our membership program. Your support makes big projects like this possible, makes our entire show possible, and we are so grateful. If you are not yet a member or you've been thinking about giving more, this is a perfect time to take the plunge because if you join or re-up now, you'll get a gift. And it's a limited edition Week of Sharks hat. I wanted it to have, like, a fin on top, but then everybody else vetoed that idea. And fair, like, I don't think I would even wear that in public. Instead, you're gonna get one designed by the Maine-based artist Ty Williams. It's beautiful, something you would actually want to be seen in in public. And it gives you a chance to show the world that you support our show. It's available to everyone who joins The Lab this month, even for as little as seven bucks a month. You can join at Radiolab.org/join. Existing members, check your email for details.

LATIF: Tomorrow is our last day of the week of sharks, and we are going from some of the biggest fish in the sea to some of the teeny tiniest. Catch you tomorrow!

[LISTENER: Hi. I'm Lisa, and I'm from Plano, Texas. And here are the staff credits. Radiolab was created by Jad Abumrad, and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co-hosts. Dylan Keefe is our director of sound design. Our staff includes: Simon Adler, Jeremy Bloom, Becca Bressler, W. Harry Fortuna, David Gebel, Rebecca Laks, Maria Paz Gutiérrez, Sindhu Gnanasambandan, Matt Kielty, Annie McEwen, Alex Neason, Sarah Qari, Sarah Sandbach, Anisa Vietze, Arianne Wack, Pat Walters, Molly Webster and Jessica Yung. With help from Rebecca Rand. Our fact-checkers are Diane Kelly, Emily Krieger, Anna Pujol-Mazini and Natalie Middleton.]

[LISTENER: Hi, this is Michelle calling from Richardson, Texas. Leadership support for Radiolab's science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.]

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