Episode 6: The canary of the sea

Chirp. Whistle. Creak. Beluga whales, the canaries of the sea, have a lot to say. But noise from ships can drown out their calls, putting calves in danger. What happens when humans press pause during the coronavirus pandemic-and finally give ocean life some peace and quiet?

Photograph by Flip Nicklin/Minden Pictures

Chirp. Whistle. Creak. Beluga whales, the canaries of the sea, have a lot to say. But noise from ships can drown out their calls, putting calves in danger. What happens when humans press pause during the coronavirus pandemic—and finally give ocean life some peace and quiet?


VALERIA VERGARA: It was a very, very foggy evening. I could see nothing. I would extend my hand in front of me and I couldn't see my fingers.

AMY BRIGGS (Host): Marine biologist Valeria Vergara was studying beluga whales in the Arctic.

VERGARA: My tent was right by the water, and the bay was filled with over 500 belugas. And there wasn't a single moment of silence. These whales were constantly communicating with one another.

BRIGGS: Beluga whales chirp and whistle and creak. They use these sounds to talk with each other.

VERGARA: And at that moment, I had this just intuitive understanding of what it must be like for an animal that—just like I was at that moment not seeing because of the fog—an animal that navigates in dark situations very often and that relies on these constant sounds to stay in touch with its companions. The sense of sound is just absolutely key to a whale. It is everything, really.

BRIGGS: It’s everything, and yet whales are struggling to hear each other. And not just belugas, but all types of whales, all over the world. Because as economies around the world have become more interconnected, more ships are crossing the oceans. And that means more underwater noise—or as Valeria calls it, acoustic fog.

VERGARA: We're a visual species. So we need to think about these things in visual terms. And it would be as if a group of us suddenly got lost in this thick, thick fog and lost the ability to see one another.

BRIGGS: That would make it hard to drive, hard to walk, hard to do anything, really. Like thick fog, noise has had a serious impact on marine life, and there were no signs of it letting up–until COVID-19. The pandemic forced humans around the world to press pause—which means whales could finally enjoy some peace and quiet.

I’m Amy Briggs, and you’re listening to Overheard at National Geographic: A show where we eavesdrop on the wild conversations we have here at Nat Geo—and follow them to the edges of our big, weird, beautiful world. This week: What happens to whales when the shipping noise almost stops? We finally have a chance to find out.

More after this.

VERGARA: Sound is to whales like vision is to us.

BRIGGS: Valeria Vergara has been studying beluga whales for nearly two decades. She’s a research scientist with the Ocean Wise Conservation Association in Vancouver, Canada. Belugas are a smaller species of whale. They sort of resemble dolphins. They’re born grey, but get whiter as they age. But it’s what they sound like that Valeria studies.

VERGARA: Whales basically—including belugas, but all whales—use sound for nearly every aspect of their lives. They use sound to communicate, to maintain contact with one another. Sound is the glue of their societies to navigate, to detect prey and avoid predators.

BRIGGS: And for belugas, sound is absolutely essential because they live in the Arctic, where it’s dark for half the year. Maybe that’s why they hear a whole lot better than we do.

VERGARA: We humans hear up to 20 kilohertz in the best-case scenario. Beluga whales can hear sounds all the way up to 150 kilohertz in frequency. Frequency—you have to think about frequency in terms of pitch. So imagine keys on a piano.

BRIGGS: So belugas have a lot more keys on their pianos than we do.

VERGARA: There's also the fact that water transmits sound much more efficiently than air—five times faster, in fact, and over much greater distances.

BRIGGS: And it’s a good thing too, because it’s much harder to see in water. So it makes sense why whales would rely on sound. And the belugas that Valeria studies...they’re a particularly chatty bunch.

VERGARA: Early mariners call them canaries of the sea because they could hear their whistles and chirps very easily through the wooden hulls of ships.

BRIGGS: Valeria has identified 28 different types of beluga sounds, but the one she studies the most is what’s essentially the beluga’s “hello”—also known as a contact call.

VERGARA: They are used for group cohesion and to maintain contact between mothers and calves. Those contact calls sound very different than the rest of the beluga repertoire. They sound like a creaky, rusty door instead of their regular chirps and whistles.

BRIGGS: Valeria sent me a recording from the Arctic. You can hear the beluga’s contact calls pretty clearly.

[Valeria’s voice memo]: Contact calls in recording [whale sound], and little calf—I lost sight of it but I’m sure it’s near [whale sound], and we have about ten animals within fifty meters of the boat.

Valeria says whales aren’t the only species to use contact calls.

VERGARA: Imagine—I don't know—30 humans in a dark room and we need to identify each other. The way to do that would be to enunciate your own name. It's sort of like wearing an acoustic tag. So you would call around, I'm Amy, I'm Amy here. And I would say, I'm Valeria, Valeria here. And so people would know where I am and who I am without seeing me.

BRIGGS: And in this sort of situation, both humans and whales can zero in on contact calls.

VERGARA: Contact calls in all species, including humans, have evolved to pierce through the chatter of the species—the background chatter of the species—very effectively, so that even if you're far away from your kid and even if there is many other vocalizations being produced by your same species, you can pick out the contact call of your kid.

BRIGGS: As a parent, I know how important that ability is. And for belugas, it can boil down to life or death.

VERGARA: If a calf calls, a mom can hear that calf up to about 500 meters’ distance, but in very noisy scenarios—with a lot of pleasure boats, for example—that distance is reduced to about 100 meters. Then there is the possibility that if mother and calf inadvertently separate—because of some cause of disturbance that makes them separate—the mom won't be able to hear the calf and orient towards the calf. And the little calf might be too young to understand how to orient and find its mom.

BRIGGS: And since baby calves are entirely dependent on their mothers, getting separated could mean that they don’t survive. Marine ecologist Michelle Fournet studies the impacts of noise on whales at Cornell’s Center for Conservation Bioacoustics.

FOURNET: So it is a common response to noise that whales will call louder. They can also call more often to try and increase their probability of detecting one another. They often will increase their pitch, so they'll call higher in frequency to try and call above low-frequency noise. Or sometimes we will see the opposite—that whales will stop calling altogether, and they'll wait until the noise has passed before they begin to call again.

BRIGGS: Michelle says whales cope with loud noise just like us.

FOURNET: Humans do this all the time. If you go to a rock concert and you are trying to have a conversation, you will shout. And so we see that whales will do the same thing.

BRIGGS: But here’s where it gets harder for whales. Imagine never getting to leave that rock concert.

FOURNET: One of the big things that can happen if the noise is loud enough and chronic enough is that we actually can deafen the animals. We can physically harm them. Just like you have buzzing in your ears after you go to a loud concert—that's called a temporary threshold shift. It means for a few hours or days you don't hear as well. But there's also a permanent threshold shift, where the animals simply can't hear as well. And it sticks.

BRIGGS: So what’s making all this noise?

CRAIG WELCH: First off, everything in the ocean causes noise.

BRIGGS: Nat Geo writer and friend of the show Craig Welch has been writing about the ocean for more than two decades now.

WELCH: Wind causes noise, waves cause noise. And then when you add the human element: you have cargo ships and commercial fishing vessels, and, you know, recreation boats out on the coastal waters.

BRIGGS: And then there are the container ships.

WELCH: First of all, they're massive. They're like several football fields in length. They will have like a big sort of navigational center on the front end. And then it's basically an empty back port that is usually filled up with these box containers. And these containers are essentially what you would see on a train.

BRIGGS: Big, colorful, metal containers. At one point or another, a lot of the things we own crossed the ocean in one of these.

WELCH: The computer that you're typing on, you know, the clothes that you're wearing, you know, your car. I mean, everything that we as consumers buy, either all of it or parts of it came probably by ship from somewhere.

BRIGGS: Because that’s what it means to have a global economy. Factories are set up in countries where labor is cheapest and [goods are] sold wherever there’s a market demand. It’s a trend that’s been on the uptick for a long time now.

WELCH: You know, the container ships alone—there’s at least a two- to threefold increase in shipping traffic around the world just in the last two decades. I mean, if you imagine—just think about how much globalization has changed, starting back in the 90s with NAFTA and then sort of moving up through the years, as we've opened up economies across the world and the U.S. and China started doing more and more trade. That means more shipping. And all that's going by sea.

BRIGGS: And now, because of climate change, more and more sea ice at the top of the world is melting, and some of these ships are starting to pass through the Arctic Circle.

WELCH: Because it's a shortcut. if you're a business trying to get your goods from one place to the other, you're trying to figure out how to do it in the fastest, most economical way possible. And going across the top of the world is shorter than going all the way around the other side.

BRIGGS: And marine ecologist Michelle Fournet says ocean trade is not going to stop any time soon.

FOURNET: We're not going to take all of the boats out of the ocean. Those are not realistic things that we can say, on any given day, that somebody will give you permission to do, barring something like, you know, like a pandemic.

BRIGGS: A pandemic. You know, like the one we’re all dealing with right now.

FOURNET: I'm not going to praise a pandemic. I'm not. But I'm not going to waste this opportunity either.

BRIGGS: Because it is an incredible opportunity for scientists who study ocean noise. A silver lining on an extraordinarily dark cloud.

FOURNET: Oh, it's gonna be the most important work we've ever done. It will be the first time that we've been able to technically record a baseline for these animals in our history of studying them.

BRIGGS: Because of the pandemic, ships around the world were docked, which means shipping noise declined, and in some places, it nearly ceased.

FOURNET: Now what we're going to have is an actual documentation of what a quiet ocean sounds like, and what whales do when the ocean is quiet. We've never had that before.

BRIGGS: No organization is funding her work. Funding takes a long time to secure, and Michelle knows the moment of quiet won’t last.

FOURNET: And so I went out and put two hundred yards of line on my credit card.

BRIGGS: And she also called on friends and colleagues.

FOURNET: Relationships. Relationships are what is funding this work. A network of people that care about this ocean is who are funding this work. And right now, we're doing it on as large a scale as we can from—just like everybody else—from our dining rooms, from our kitchen. Yeah. No one is funding this work.

BRIGGS: And this is where the silver lining stops and the dark cloud of the pandemic returns. In good times it can be challenging to secure funding for scientific research. The global economic crisis is bound to make that situation even worse.

FOURNET: I don't know if anyone will fund this work and they might not. And that would be really troubling because it might mean that we collect this data and that we simply can't analyze it, because at that point, we're all looking for jobs.

BRIGGS: But at least they’ll have the data. And at some point down the line, when they do analyze it, they might uncover mysteries that until now have been shrouded by noise.

BRIGGS: Do you have any predictions for what you think we might find out?

FOURNET: I do. I think that what we're going to find is that the complexity of the conversation increases, that the conversations are going to get more complicated.

BRIGGS: After all, that’s what would happen with people.

FOURNET: If you are at a really crowded coffee shop, it's really, really noisy and you're trying to have a conversation with a friend. You might use short sentences and be really to the point and really straightforward because it's noisy. And if you want to get the point across or you're trying to talk to a barista, you’ve got to be really, really clear and really concise. But let's say that you're sitting at home on the couch and it's perfectly quiet. The quality of the conversation can get much more nuanced.

BRIGGS: We don’t know if this happens for whales. And the only way we’ll find out is if we listen. Michelle says it’s a humbling task.

FOURNET: We have this human tendency—and I hear it all the time when I take people out to see whales—that we want the whale to jump out of the water. We say, oh, I want it to breach. Oh, it did that just for me. Oh, it's waving to me. Oh, it's putting on a show for me. And we love that. It makes us feel special. It makes us feel like nature is coming and introducing itself. But the truth is that these animals don't exist for us. They exist despite us. And these animals definitely are not here to put on a show for us. They are existing in their own context and in their own right.

And at least for a little while, they’re able to do it without us getting in the way.

More after this.

BRIGGS: If you like stories about whales, check out the very first episode of Overheard: Humpback Whale Song of the Summer. And in the show notes, you’ll find a story about why ocean animals eat so much plastic. The reason is surprisingly complex. There’s also a breathtaking video of hundreds of beluga whales gathering in the Arctic.

And for subscribers, read about how the thawing of Arctic permafrost affects us all. You can find these stories and more in the show notes, right there in your podcast app.


Overheard at National Geographic is produced by Laura Sim, Brian Gutierrez, and Jacob Pinter. Our editor is Ibby Caputo. Our fact-checker is Michelle Harris. Hansdale Hsu composed our theme music and engineers our episodes.

This podcast is a production of National Geographic Partners. Whitney Johnson is the director of visuals and immersive experiences. Susan Goldberg is National Geographic’s editorial director.

And I’m your host, Amy Briggs. See ya next time.


Ever wonder why ocean animals eat plastic? The answer is surprisingly complicated.

Whales around the world are still being hunted for their meat. But in Iceland that might be ending.

Also explore:

Take in the breathtaking sight of hundreds of beluga whales gathering in the Arctic.

Check out the very first episode of Overheard for another story on how whales communicate.

And for paid subscribers:

The graphics team at Nat Geo has mapped out the effects of shipping on Arctic sea ice.

Read Craig Welch’s reporting on the changing Arctic, including how the thawing of permafrost affects us all.

See photos of whales taken by a Nat Geo explorer who’s spent 10,000 hours underwater.

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