THRESHOLD CONVERSATIONS
Michelle Fournet
AMY: Welcome to Threshold Conversations, I’m Amy Martin, and today I’m talking to Dr. Michelle Fournet…
WHALE SOUNDS
and some humpback whales.
WHALE SOUNDS
AMY: Michelle Fournet is an acoustic ecologist with the Cornell Bioacoustics Research Program. She studies how marine organisms use sound to communicate, detect predators and prey, and engage with their environments. One creature she has focused on is the humpback whale. She’s recorded hours and hours of the underwater sounds they make in southeast Alaska. That’s what we’re hearing here.
WHALE SOUNDS
Dr. Fournet is trying to figure out what all of these sounds might mean, and how the whale's acoustic environment is impacted by human activities like tourism, shipping, and oil and gas exploration. Last March, all of those activities went into a screeching halt because of the coronavirus pandemic. Although Michelle would never have wished for this global health crisis—of course—the sharp decrease in ocean noise may provide her and other acoustic ecologists with a totally unexpected opportunity to study how marine animals respond to something increasingly rare: a quiet ocean.
AMY: Michelle Fournet, thank you so much for joining me on Threshold Conversations.
MICHELLE: Thank you so much for having me. It's very lovely to be here.
AMY: So our oceans are getting noisier and that affects marine life, including many kinds of whales, can you help us get a clearer picture of this? Put a finer point on it? How much noisier are the oceans today compared to say 50 years ago? Do we even know that?
MICHELLE: That is a complicated question. So I'm going to try and break it down and simplify it to the best of my ability. The short answer is much noisier. In some parts of the ocean, we see a doubling of sound every 10 years. So, orders of magnitude louder than they were 50 years ago. When we think about ocean noise, what we really need to think about is human expansion and how humans interact with the world at large. So we'll have concentrated pockets of noise, where we have concentrated pockets of human activity. And then we have these thin lines of sound that wrap the world, sort of like a ball of string, which represents all the different paths that things like shipping, oil and gas exploration, travel, as we connect port to port to port. So I would say if you were going to look at a picture of the earth lit up with sound in the 1970s, it might look like you're just starting to wrap the earth and a ball of string. But if you were going to look at the earth in 2020, at least in, let's say, let's say 2019, let's say you're gonna look at a picture of how sound interacts with the ocean in 2019, it would look like you had splatter painted, like you had wrapped with earth round and round and round and round with this ball of string. And that you were starting to get all this overlap around these major urban centers. And so the center of the Pacific would be drawn across with thick red lines and the center of the Atlantic will be drawn across with thick red lines. So saying exactly how much noisier the ocean is today than it was 50 years ago is something that, to be honest, we just don't know. And it changes day to day. It changes based on time of day. But what we do know is that on a whole, the ocean is experiencing anthropogenic noise. So, man made noise at an absolutely unprecedented rate. Human activity has changed the way the ocean sounds. And there's almost no area in the world that you can go and drop a hydrophone that you wouldn't hear sounds of humanity if you listened for, you know, a day or two.
AMY: And a hydrophone is just a microphone that you can put into the water.
MICHELLE: Yes, exactly. So a hydrophone is an underwater listening device. We can drop them down to the bottom of the ocean and we can leave them there for long periods of time, which is part of what my work entails is deploying hydrophones around the world and leaving them to listen when otherwise humans wouldn't know what was going on.
AMY: You did a great job of making something, audio visual there with your, your ball of string analogy and what are, what are some of the most tangled spots? Where, where are the loudest spots and the quietest spots? And do we even know that much yet?
MICHELLE: Yeah. That way I have a better understanding of, generally the loudest spots in the ocean are going to be near major ports of call and along shipping lanes. So the Eastern seaboard is really noisy. Major ports in Asia are really noisy. Near the ports of San Francisco and Los Angeles are really noisy. Rio de Janeiro is really noisy. Any place where you have a major port, you're going to have noise, but, shipping is not the only substantial contributor to ocean noise. We also get these major noise hotspots in areas where they're doing any kind of oil and gas exploration. And in fact, for many marine organisms, things like air guns can be dangerously loud. That sound can have so much energy, that it can damage the physical structure of things like fish and invertebrates and plankton. It is noisy enough, where if you were directly in the path of that, it would, it would deafen a whale or a seal or a human, certainly, if you happen to be scuba diving under the water near any of those blasts.
AMY: Those are tools that are used to find where oil and gas are under, under the, on the ocean floor?
MICHELLE: Exactly. Yes. So areas where we have high concentrations of oil and gas exploration, certainly that increases ocean noise. And then marine construction is another major contributor to ocean noise. So things like oil rigs when we put in ports, when we build bridges that all will permeate throughout the ocean. And then one that, we have a tendency to sometimes think a little less of is, is tourism. People enjoying themselves makes a lot of noise. So the sounds of cruise ships, the sounds of whale watching boats, the sounds of jet skis, the sounds of pleasure crafts, people heading out to go fishing on the weekend, with their small little skiffs with their, you know, maybe a single outboard engine that also makes a lot of noise. That noise really adds up. And so in, in general, you can link almost any human activity back at if you follow the train far enough to, to its contribution, to ocean noise, whether that's shipping goods worldwide, or whether or not that's getting on an airplane, which flies over the ocean, which then permeates down through the air surface water boundary. Anytime we, we go near the ocean ourselves, or any time we purchase something that has had to travel across the ocean, that's going to have some sort of acoustic fingerprint or acoustic footprint in that particular marine ecosystem.
AMY: Even planes? I didn't realize plane noise could actually make its way down into the ocean.
MICHELLE: Oh yeah, absolutely. Depending on how low flying the plane is, it will definitely bounce rate through the ocean and you can hear it, small planes in particular that are flying closer to the water. So, you know, when we interact with the ocean, we, we, we change the way that it sounds. And that's true of almost everything we do on land, but because of the way that sound travels underwater, noise underwater, or sound underwater has a much further reaching, it goes further. Light underwater attenuates very quickly. So if you were to dive 30 or 40 feet underneath the surface of the ocean, say you're scuba diving, it gets dark pretty quick. Whereas on land light attenuates pretty far. tThe opposite is true when you get underwater. Sound will travel very efficiently with very little loss of energy, which means that a sound that's made under water, can travel far and can be heard far and will be loud even at far distances. And so because of that, most marine organisms have evolved strategies to rely on sound as their principle way of interpreting the world. So for humans, we interpret the world predominantly through sight. We look around us to get information and then we use sound also as a cue, but sight is our primary principle sensory modality. For marine organisms, we flip this: they use sound to forage, they use sound to breathe. They use sound to communicate. So when we make noise underwater, they interact with it. They will alter their behavior or they will hear it. And that's partially what makes anthropogenic noise potentially so dangerous. What it means is that with our human activities, we may be inadvertently acoustically, blinding, a lot of creatures that are, that are underwater.
AMY: Acoustic blinding. I haven't heard that term before it's evocative. And when did scientists start tracking noise in the ocean and its effect on animals? How, how old is this whole discipline?
MICHELLE: You know, it's not a very long, it's not an old discipline. Bioacoustics in the marine environment is really only a handful of decades old. We started listening to animals underwater with the Navy. You know, the Navy really pioneered this concept that sound under water was a powerful tool for understanding things. And, I mean, I think some of the earliest listening devices started were in like the 1910s and twenties, but the field as a science really didn't take off until the sixties.
AMY: Well, I'm excited to get into some of the details of, of your work, but maybe just give us a little introduction to these animals, their lifespan, their, their geographical range, their size, some things about their behavior. Just kind of like a humpback 101.
MICHELLE: So humpback whales are perhaps the most well watched and among the most beloved whales on the planet and partially that's because they're a gregarious whale. So humpback whales are a coastal species and they're found worldwide and they migrate from these high latitude foraging grounds; places like Iceland, places like Canada, places like Southeast Alaska or Antarctica. And at these high latitudes where the water is cold, they'll spend late spring, summer and full foraging. And that's what they do. They are there to eat. They will gain thousands of pounds over the course of a single summer season. And they do this because at the end of the season, in the case of Northern hemisphere, whales, they'll migrate southbound into the tropics. In the case of Southern hemisphere whales from Antarctica, they'll migrate northbound also into the tropics. And once they get to these tropical regions, those are their breeding and calving grounds where they will mate, and then they will also give birth. But throughout migration, and on these tropical breeding and calving grounds, humpback wills will fast. So they’ll lose up to a third of their body weight over the course of the winter season.
AMY: Whoa
MICHELLE: Female whales, when they give birth—calves are 15 feet long and weigh several thousand pounds—and mother whales will nurse these calves for hours and hours and hours every day. Humpback whale milk is extremely rich. It's very high in, in, in, in fat, much more so than terrestrial mammals are. These calves are nursing constantly and they're gaining lots and lots of weight. And these mother whales are getting skinnier and skinnier and skinnier. And then on the flip side of that, we have male whales on breeding grounds who are actively engaged in these very elaborate breeding and courtship behaviors, which involve among other things, singing.
MALE WHALES SINGING
MICHELLE: So on breeding grounds and throughout the migratory corridor, but predominantly on breeding grounds, male whales produce these long, extremely complex, repetitive and structured acoustic signals that we call songs.
MALE WHALES SINGING
MICHELLE: These songs are culturally transmitted, which means that males will learn them from each other and then they shift and change over time. And so every year we get a new breeding song and over the course of the summer season, it starts to change ever so slightly. And it's interesting because there's not a lot of animals that exhibit social learning, in the same way that humpback whales do. So these songs are very, very complex.
AMY: How long are they?
MICHELLE: Humpack whale songs can be up to 20 or 25 minutes long.
AMY: Whoa.
MICHELLE: And if you were to drop a hydrophone in Hawaii during the breeding season, 24 hours a day, you'll hear somebody singing.
MALE WHALES SINGING
AMY: And so when you say they're, they're culturally transmitted, just to make sure I understand that. So, you're saying that like these, these male whales within a certain cluster, they all are singing the same song, or just sort of similarly related songs.
MICHELLE: No, they're all singing the same song. So all male humpback whales within a breeding population at a given time will sing the same song, but the song will evolve. So it will slowly change, over the course of a breeding season. So there's a really interesting example of this that probably can sort of demonstrate the cultural transmission best. In Australia, they have humpback whales on the Eastern side and they have humpback whales on the Western side and they're discrete populations. They don't interact on their breeding grounds and they sing two separate songs, an errant humpback whale from one region in some way, shape or form opted to go the other direction one year. And it infiltrated the song of the, of the other whales. And so one singer came in with a new, with a novel song type that hadn't been heard there before. And what happened was all of the male whales changed. They all adopted the new song. And so that's been dubbed a cultural revolution, that there was the introduction of this novel song type. All of the other male whales are like, hey, I want to sing what he's singing over the course of the breeding season. They adopted this new song type.
AMY: It's like the British invasion and suddenly everybody's imitating the Beatles or something.
MICHELLE: Exactly, exactly, exactly. It's like East meets West and we all switch over.
AMY: Why, why would they, well, I guess I want to ask why would they switch? But I guess first I need to understand why do all the males in a certain cultural group sing the same song? Doesn't that.. I would just sort of assume that they're competing for female attention. And so it would behoove them to, to sing an especially cool song that's different from their buddies, as opposed to them all singing the same song. What's going on there?
MICHELLE: All right. So that is also a complicated answer. Why do all whales sing the same song? The answer is we don't know. In the animal kingdom, it is very common that males of a species will sing the same song. Birds, for example, generally will sing the songs. Even if those songs are culturally transmitted, even if they're learned, and the male that sings it best likely will get the girl. But for humpback whale song, there's evidence that song may serve several social functions, that it's not just to woo a female, that it also serves as a male-male interaction. You know, I, I hate to be the biologist that says, we don't know why we all sing. We certainly know that they sing in a breeding context. There's lots of evidence that it is for mate attraction and that it's for competition. But the truth of the matter is, even though we're talking about an animal that might be 40 feet long and weighs 80,000 pounds and it jumps out of the water and it lives right off of our coastline, there is a great deal we don't know. And trying to understand the function of a sound is very difficult. And I might flip that question on its head and ask, like, why do people sing?
AMY: Yeah.
MICHELLE: And that's a complicated question. And if we can't even figure it out in our own species, in this nice, concise way, when we can analyze it and research it and talk to each other, it is that much more difficult to try and understand why a humpback whale sings when we can't just ask it. And we don't understand. And we can't yet put our own human perspective into the mindset of a whale, so much of how we interpret their actions is, is placed through the lens of human behavior.
AMY: Yeah.
MICHELLE: And so it's really important that we try and frame their behavior in the context of their perception. So why do whales sing, well, how do whales hear? Well, all right, once we figure out how whales hear, what are whales hearing? Once we know what whales are hearing, we can know how they might be filtering the song. And then we might know something about what exactly that song is for.
AMY: I love this answer actually, because it just opens up mystery upon mystery. And I also love it because it leads me to my, to the next question I was going to ask you, which was how do whales actually produce and receive sound? Like, we have two ears and vocal chords and a mouth, but what do humpback whales have for both the receiving and the production of sound?
MICHELLE: So whales also have two ears, although that isn't necessarily, I mean, certainly they hear through their ears, but not in the way that we might think. So mysticetes are, are baleen whales, or sort of large, planktonic, filter-feeding wheels. Those are mysticetes whales. Up until very recently we, we didn't have any, any concept at all as to how mysticetes hear. There have been a handful of publications that have come out on the anatomy of large whales that indicate that in the same way that we collect sound through our pinnae through our ears, and that gets filtered through, into our ear canal. There is evidence that for, for baleen whales, that they're actually receiving those vibrations partially through their bones, through the actual bones in their skull. And that, that is vibrating up and transmitting that sound close to the inner ear so that they can have that push pull pressure, which is necessary for, for hearing. But we don't know the exact mechanism or the sensitivity for how that works.
AMY: Wow. That's awesome. Like thinking of your whole body being an ear, or your head anyway.
MICHELLE: Yeah, yeah. And alternatively sound production we know a little more about. Baleen whales have something called vocal folds, which are analogous to vocal chords in humans. And unlike humans, whales do not need to open their mouths in order to produce sound. They can produce on with their mouths closed. And so they will actually move air back and forth through different sinus cavities, going back and forth over those vocal folds. How they manipulate those vocal folds to produce the range of sounds that they produce? We don't know. Humpback whales produce an incredibly diverse repertoire of sounds, an almost unclassifiable number of sounds that they are capable of producing. We are still teasing out, which sounds are produced as a byproduct of other activities. The way that, you know, you might sneeze, that makes a sound, but we wouldn't call it a vocalization. Humpback whales also make several sounds that were like, is that a vocalization? Or does it have allergies?
AMY: (laughter)
MICHELLE: It can be difficult to tell. The nuances of this are still again, um, we're still working a lot of, of, of these particular things out. And part of that is because these are animals that cannot be kept in captivity. You can't put a humpback in an aquarium. It's not, it's not possible, they're too large. They require too much space. They would, they wouldn't survive. So so much the bulk of what we do is about being on the water, getting in the ocean, being near the ocean and coming up with the best possible ways we can to take advantage of, of naturally occurring situations and to observe how these creatures are interacting with each other, how they're functioning, and even just really simple things like how big are they? What do they eat? What do they say? Simple questions that are very hard to answer.
AMY: Yeah. And just to connect back up with what you were saying in, in response to my question about, you know, why they all would sing the same thing as I understand it, what part of what you're saying is in order to answer that we have to first step back and realize that, like what we're hearing, when we're able to capture whale sound, that might not actually be the experience of what that sound even sounds like to them, because we don't fully understand how their hearing is that... was that part of what you said?
MICHELLE: That is exactly right.
AMY: And that's fascinating to me that, like, we think we're like, Oh, here's a whale sound. And we're thinking it's super interesting and it might sound completely different inside their own heads. And it just sort of feels like how, I don't know. It feels almost kind of magical, I guess.
MICHELLE: It's a great treat as a biologist when, when there are unknowns. The things that we don't know, allow us to ask creative questions based on the laws of nature. If you think, think about there's a structure to this world. There's a structure to how evolution functions. There's a structure to how chemistry functions, but nature is filled with unknowns. So part of my job as a scientist is to take the skeleton of nature and use my imagination to fill in what the flesh might be. And then to go out into the world and test those hypotheses to see, do I see the fingernails and hair and skin of nature, the way that I imagined it, or, or is it something else? But before we could ask why do all male whales sing the same song, we had to learn that all male whales sing the same song. And that was quite a feat. That was an enormous discovery because before we could do that, we had to figure out that it was in fact male whales that were singing. And then before that, we had to figure out it was whales that were singing and those, those discoveries learning, gaining that information took decades. So it is a slow and steady process of imagining, cultivating questions, testing those questions, and then sharing the answers.
AMY: More whales, and more of my conversation with Dr. Michelle Fournet, right after this short break.
BREAK #1
Ami Vitale Event Promo: Angela
AMY: Welcome back to Threshold Conversations, I’m Amy Martin, and I’m speaking with Dr. Michelle Fournet, a fellow at the Center for Conservation Bioacoustics at Cornell University. One of her areas of expertise is the acoustic ecology of humpback whales.
AMY: What, what are the different kinds of sounds that whales make, or maybe I should say, how, how do you or other experts categorize the different kinds of sounds they make as we hear them?
MICHELLE: So, for humpback whales, we basically put their sounds into three very broad categories: there’s song, which we've talked quite a bit about, which is produced only by males, male whales, the only ones who sing. And then there's also percussive sounds, that's the sound of a whale's body hitting the water. So when it slaps its flippers or its pectoral fins, or when it slaps its tail flukes down on the water, when it breaches, all of those things make these loud percussive sounds. And then there is what I think are perhaps the most interesting of all the sounds that humpback whales make, which are the calls or non-song calls. They're also called social sounds or social vocalizations.
FEMALE AND MALE WHALES CALLING
MICHELLE: Humpback whale calls are produced by male whales, female whales, old whales, baby whales. All of the humpback whales in the world will produce a suite of calls. And these calls are all of the sounds that whales make outside of the context of song.
FEMALE AND MALE WHALES CALLING
MICHELLE: And the field of study for studying these, these social sounds, these non-song vocalizations is very new, very new. Up until the mid to late 2000s, there were only a handful of people who had described the fact that humpback whales produce sounds outside of song.
AMY: That is very, very new. Indeed. That's like 10 years ago.
MICHELLE: Oh yes. Yes. The male whales when they sing are really loud and really gregarious, and the song is so complex and interesting and beautiful. But from a science perspective, it's this great scientific mystery and, and, and it's loud and it's long and it's present and it's gregarious and it's showy. And that is often the case with male breeding breeding behavior. It wasn't until 2007 that anybody sat down and said, hey, you know, we should probably catalog what the rest of the whales are saying, what they're saying the rest of the time.
AMY: Is there a gender bias here I have to ask? Cause it's like, it's just striking that we were so fascinated by what the dudes were doing. We weren't paying attention to the women and children.
MICHELLE: You know, I think about this a lot. Is there a, is there a sex bias in how we've studied whales? It certainly came out that way. I don't know that there was an intention to study just what the males were saying. I think that song was an obvious choice to study. To study what a female will say was a much less obvious choice. And, and it took some intention to go out and try and collect these much more subtle sounds and this much more subtle calling behavior.
FEMALE AND MALE WHALES CALLING
MICHELLE: You know, when I first started my work on humpback whale social sounds, there were maybe 10 researchers worldwide that were interested in studying calls. Like we could all sit down for coffee and comfortably talk.
AMY: Wow.
MICHELLE: And every year we get new recruits, we get people that are interested in sort of the other side of humpback whale communication. And so as a result, what we have now is a new generation of scientists who are addressing a new question. You know, the previous generation of scientists were predominantly male and predominantly white. And we are just now starting to intentionally make that shift to include a broader representation of voices in the marine mammal science community: representation of the voice of, of women in science, people of color in science. And I don't know if there's any relationship whatsoever between these two things, but I do think that it's an interesting moment that when we are really trying to give voice to human representation in the field of marine mammal science, that that is also coinciding with an intention to give voice to underrepresented demographics of marine mammals themselves. This new generation of, of more diverse marine mammal scientists is listening to these subtle sounds, listening to the voice of female whales, listening to the voice of, of quiet whales, that we're making an effort to paint a more complete picture to the best of our ability. I mean, we are succeeding in some areas and making very little progress in others, but, in the same way that we are expanding the culture of science, we're also simultaneously expanding our, our knowledge of the culture of these animals and their social structure just as we work to, you know, expand the completeness of our own.
AMY: That is fascinating to me. And it makes sense to me because I think anybody knows who's, who's paid attention to it, that who we are, how well our voices are listened to, by other humans has a lot to do with, with who we are, how we're perceived and some of those. So those different categories of, of, of power and privilege. And so it just makes sense to me that that would also affect who we are as listeners, in terms of what we, what we are prone to notice what we pay attention to, what we're motivated to, you know, commit decades of work to studying, you know, that's all, that's all influenced by who we are as people. So it's a great, it's a great argument for why we need more diversity in science just to make us, make us smarter as a species.
MICHELLE: Yes, I absolutely agree.
WHALES CALLS
AMY: So like the little “ooooo,” that's a call?
MICHELLE: All of these are calls, so calls are incredibly diverse. And they can be really varied.
WHALE CALLS
MICHELLE: So, this is the, this is a series of sounds that were recorded in Southeast Alaska in 2016. And all of these are calls. So none of this is song. What you hear in this recording is, a very long feeding call that is produced by a single animal. So, that animal is foraging at the moment. And then behind that sound, what you're hearing is anywhere from 10 to 15 different animals that are vocalizing either to each other, in small groups, or, or producing sounds perhaps to, to slur up fish, but this particular clip includes well over a dozen animals.
WHALE CALLS
MICHELLE: There was I think, upwards of 30 whales that were in the area. And, and, and let me say that that's unusual. That is, that's not a common behavior for humpback whales. Humpback whales in Southeast Alaska are often traveling in small groups. They're often traveling alone. But this day we had this particularly large aggregation. And as a result, we got this really quite extraordinary cacophony of sounds that we don't often get.
AMY: How deep were the whales, do you think roughly?
MICHELLE: Well, I think it was changing. The water in that area is about 250 feet deep. And I'd say that the whales were going up and down the water column as they forage, but plenty of them were right by the surface. When we recorded that, it was it, I was on a very small boat and we were dead in the water. We always record dead in the water and we always position the vessel far away from the whales so as not to disturb them. But the nature of this particular aggregation of whales is that they were moving around. And so they ended up sort of milling about a hundred yards off of the boat. And I was listening to the hydrophone. And so I could simultaneously hear the sounds of those animals underwater, but I could also hear the sounds of their breath as, as various members of this, of this group of whales were surfacing. Oh, it was extraordinary. So you could hear the whales as they were, that *puff sound* of, of the whale as they would exhale along with the, the, the sort of squeaks and whistles and whatnot of the wheels as they were for, as, you know, as they were calling underneath the water.
WHALE CALL
MICHELLE: So that sound is called an “ah-ooga.” And then that long operatic sound that you're hearing, that's the feeding call.
WHALE CALL
MICHELLE: So, that call is only heard in Southeast Alaska. And more recently it's expanded southward into parts of British Columbia. And that sort of long operatic call is produced, it's in the peak hearing range of Pacific herring. And as a result, when herring hear that call, they flee, they, they swim away from it. And humpback whales use that as a form of manipulation to force the fish towards the surface of the water so they can be, more easily eaten.
AMY: Wow. So they're calling intentionally for them to hear, like, you'd think they'd want to sneak up on them, but instead they're like, “here we come” and that drives them into the place where they're going to be more easily snatched up.
MICHELLE: Exactly. So they produce that particular feeding call in congress with blowing bubbles. So they blow bubbles in this ring around the school of fish, which also elicits an anti-predator response. And so those herring will actually clump up in response to the bubbles and then move away from the sound.
AMY: What's the “harumph, harumph” sound?
MICHELLE: So that sound falls into what we call the pulse call class. To be honest, that particular sound doesn't have a name because we haven't... cause it's really hard to classify. That sound is produced from time to time, but it's not highly stereotyped. So we haven't been able to nail down exactly what it is. But it is some sort of pulsed sound. And we think that these pulsed sounds help to facilitate closer range social interactions, but to be perfectly honest, we don't know why they produce them. We have not gotten that far yet.
WHALE CALLS
AMY: So those are some calls, let’s hear some song again, just so we can compare the two.
WHALE SONG
AMY: I think the, the, the lay listener will probably be able to make some differentiations herself or himself, but, but as an expert here, what do you notice right away that's different between a song and the different calls?
MICHELLE: So the biggest difference between song and calls is structure. When you hear the song, you can hear that they produce the same sound over and over and over again, and then they switch and they produce another sequence of sounds over and over and over again. So they get this sort of, A, A, A, A, BA, BA, BA, A, BC BC, BC, There's this structure. And so what you get is you get song units that are produced in these sort of phrases, then those phrases are repeated. And then all of that in this sort of hierarchical, structured situation is put together to create song, whereas calls occur kind of haphazardly. You, you get a sort of random smattering of calls here, random smattering of calls there. They're produced without a lot of structure and often they're produced in isolation. So even though the clip that we listened to has a lot of sounds in it. Most of the time when you drop a hydrophone on a foraging ground, you hear very little and, and then when they do start to call, you hear one or two sounds that are repeated and you'll get most commonly, you get a call called a whoop call, which it goes *WHALE WHOOP.*
AMY: And here’s a recording of a whup:
WHALE WHOOP
MICHELLE: Whoop calls are amazing. The really amazing sounds, and they are easily the most commonly produced sound type that you'll hear in Southeast Alaska, but not just in Southeast Alaska. This is one of the most commonly produced call types heard anywhere in the world. And this I think is really interesting. This is, is one of the things that really keeps me up at night. Song changes and song changes based on which population is saying it and changes from year to year to year. But those whoop calls don't. They're produced by every population of whales and humpback whales have been producing what calls for generations. So, why? Why is it that that sound sticks? That whales that have never met each other that have been separated genetically by millions of years? So genetically isolated population of animals that will never interact that have never interacted that haven't, that don't have a shared lineage, in any kind of recent history, they're all producing the same sound. Now something tells us that ecologically, that sound persists because it's important. That sound has stayed in this acoustic repertoire for each of these populations of animals, and it persists generation after generation after generation, because it's meaningful to that animal's life history. And as a result, a lot of what I have done and what I am focusing my efforts on is really trying to understand these calls, not the calls that are changing over and over and over, not the calls that are culturally transmitted, but my interest is in documenting which of these calls are likely to be innate and what the function and role of these innate calls is.
AMY: Well that leads me to this, this 2018 study. You were the lead author on which I think one of the main quotes from the conclusion was “humpback whale called types persist across multiple generations.” And I was wondering if you could explain in layman's terms, what that actually means. Maybe you just did, but can you say more about persisting not only across... in different populations but across multiple generations?
MICHELLE: Yes, absolutely. So in the 1970s, humpback whales were critically endangered. Their populations were, were, were critically, critically low. They were on the brink of extinction and in the 1970s, Roger Payne went to Southeast Alaska and he sat in a small boat and he dropped a hydrophone and this is what he heard. He heard humpback whales producing whoop calls and humpback whales producing growls and humpback whales producing swaps and droplets. These really lovely little disorganized clusters of calls. And luckily, since the 1970s, those populations have rebounded. Those whales gave birth and their offspring produced whoop calls and produced growls and produced swaps and droplets. And then those animals gave birth. And those populations, those new animals, the next generation produced growls and whoop calls and swaps and droplets. And what we found is that over time as the population grew, that these call types persisted and that when we dropped a hydrophone every decade from 1976, until two thousand and... I think 2012 was the last year of the study, that whereas they could have fallen out of the, of the acoustic repertoire, they could have stopped being part of the conversation, the way that slang might've or, or the way that song from 1976 sounds very different than song in 2012. But instead as the population grew, these call types stuck around and what's more is that they didn't just stick around in Southeast Alaska. When we listen to the sounds, you know, generation after generation of generation of whales producing these sounds, and then we realized it's not just Pacific whales that produce them, it's Atlantic whales. It's not just Atlantic whales, it's Southern hemisphere whales. And, and so again, this suite of calls, are hanging on in a way that in the rest of the humpback whale acoustic repertoire, sounds often turnover or disappear, but these call types did not. These five call types, you know, stuck it out generation after generation.
AMY: Do we have any idea of why or what they're saying? Are they, I mean, it's just so tempting to imagine they're telling stories, or they're passing on knowledge, or, do you have any kind of guesses or hypotheses that you're trying in terms of decoding it?
MICHELLE: You know, I do. I do. And partially this is what we're working on now, and I'm really, really excited about it. There's a lovely study. I think we want to say it's a 2011 study that Lauren Wilde and Chris Gabriel published called, um, “Putative Contact Call Produced by Humpback Whales.” And they propose that humpback whale whoop calls that loop that is so, so ubiquitous amongst humpback whales worldwide, they propose that that call might be a contact call and that humpback whales would produce that call when they were interacting with other humpbacks, sort of as a way of alerting one another to their presence. Like I am here. I am also here. And so in 2019, we just, this past summer, we went to Southeast Alaska with a speaker and a hydrophone array. And I took recordings that I had been making in Southeast Alaska over the past 10 years of this humpback whale whoop call. And we played it to the whales to see if they would call back and to see whether or not this call was in fact, a contact call and the data's still coming in. We know we're still doing the analysis, but, but there's, there's some really strong evidence to support the fact that this call might be a way of, of maintaining social interactions, facilitating social interactions that it might in fact, be a counter call that if you whoop to them, if all goes, well, maybe they will whoop back.
AMY: That is so cool. It's like, you're, I mean, when you played it and they I'm assuming they must have responded, did you feel like you had just like, kind of, I don't know, gotten the first letter on the Rosetta stone or something like, hello, hello from the surface, hello, from this other part of the planet. I mean, how did it feel?
MICHELLE: It felt amazing. It felt absolutely amazing. It felt serendipitous. And then I had to sort of take a deep breath and, and, and remind myself that they produce this call all the time and that possibly they were talking to me and possibly they were just doing what they do anyway. And, and, and so I'm in the process of teasing that out, But, but it, but I guess without giving too much away because the study's not done, there's just a lot of evidence that these animals are interacting with each other in a really nuanced way. And that we are getting closer to figuring out what those nuances are, because the other really interesting thing about that particular call is there's a good chance that it contains identifying information that it contains this concept of, of voice. Not that it's a name per se, you know, dolphins, have dolphins have signature whistles. So they, you know, they produce sounds that are individual they're learned, but you and I can identify people by the sound of their voices. There is some evidence, and again, we're still working on this. These results are very, very preliminary, but there is evidence that that same concept of quality of voice that is recognizable could be contained in, in these little contact calls.
AMY: Oh my gosh, that just absolutely gives me chills. And as soon as we can travel, I have to come hang out with you. [Inaudible] this is so cool. Because it makes sense. I mean, we, we can, I mean, people who haven't heard the voice of someone that they knew when they were, when they were teenagers, you know, at least after the voices have like changed into their semi adult form, you can hear that voice 40 years later and immediately have a connection of like knowing who that person is. And, I, it just makes sense to me that such an intelligent animal would, would be learning something about the other individual through the quality of the voice. I don't know, I'm no scientist, but that makes sense to me.
MICHELLE: It does make sense. And it makes sense also because humpback whales will maintain relationships for years and they'll maintain relationships over very, very long temporal and also geographic scales. So it's not like, like, like killer whales killer will stay with their mothers for life. They stay in these really tight knit family groups. Humpbacks don't do that. But humpback whales do maintain these social affiliations that will last for, for potentially, for decades. And we've observed this in Glacier Bay, and we've seen this in the North Atlantic that, that whales will repeatedly affiliate with the same animals. And the question is, how do you know who to affiliate with? How do you know that...who they are? How do you find each other? And the answer that makes the most sense intuitively when you think about how sound travels under water is to think that they're finding each other by sound. So, yeah. Listen for the sound of the voice of your, of your comrade. And, and, and then the relationship could potentially be maintained.
AMY: And when you say they affiliate, does that mean, are you saying like they choose to migrate with each other? They choose to forage with each other?
MICHELLE: They choose to forage with each other. So we have groups of animals that will repeatedly aggregate to, to forage together. Sometimes in large groups where we get that bubble netting behavior, where they produce feeding calls and blow bubbles, and we get animals that will repeatedly get together to do this coordinated foraging, but then sometimes the relationships are more subtle. Sometimes it's two individuals that will affiliate for a few days. So they'll travel together, they'll eat together, they'll socialize together and then they'll break up, but then a week or so after that, they'll reconvene, they'll come back together, they'll travel together, they'll forage together, they'll socialize together. And, and we've seen this in a couple different populations where these animals exhibit these sort of short term relationships that sort of ebb and flow, in and out and in and out, but that they, they associate with each other more so than with other animals. And that they'll do this repeatedly over years.
AMY: And how long, what is the lifespan, the average lifespan for a humpback?
MICHELLE: Oh, humpbacks can live a long time. We think that humpback whales can probably live upwards of about a hundred years. It's a little hard to say, right? Because for so long we were hunting these animals. And what that means was, you know, I mentioned that in the 1970s, our population was severely, severely depleted. And we're only just now starting to get into whales that are able to grow old. So we know that humpback whales can live to be into their seventies and eighties. There has been a sense that they can live to be in their nineties. A good guess is to think that humpback whales could live to be upwards of a hundred or so years old. Other types of baleen wheels can live to be even older than that. Bowhead whales can live to be over 200 years old, you know, really, really long lived creatures. So when we think about whales, when we think about humpbacks, you really have to adjust your sense of scale. We have to think about them from the perspective of an ocean basin. Relationships that span miles, relationships, that span years, really, you know, voices that span generations. We have to think bigger in every sense of the word when we try and understand how these animals interact with the world and how they interact with each other.
AMY: We’ll have more, after this.
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PROMO SWAP
AMY: Welcome back to Threshold Conversations, I’m Amy Martin and I’m talking with acoustic ecologist Michelle Fournet. Today we’re focused on her research on humpback whales in south-east Alaska, but Dr. Fournet also studies fish in Florida’s Everglades National Park, and she founded and directs the Sound Science Research Collective, a nonprofit organization dedicated to excellence and equity in science. We have links to Michelle’s various projects on our website, including photos and audio from her field work with the humpback whales we’re talking about here. In this last segment of our conversation we focus on how our human activities could be impacting the whales. And to begin to understand that, I asked Michelle how far humpback voices carry underwater.
MICHELLE: It depends. It depends on how noisy the environment is. It depends on how loud the call is, and it depends on the environment. And that's actually one of the things that we do a lot of research on is how far away you can detect a humpback whale. Song can be detected for many, many miles because they're singing really loudly. So, if you have a quiet day and you have a singing whale, you might be able to hear him for 10, 20 miles, potentially longer based on how the ocean's doing that day. If you have exactly the right ocean properties and your whale is at exactly the right depth, you could potentially hear that song for 40 or 50 miles away. Blue whales can be detected for much, much further. Some animals can be detected for hundreds of miles. But the kind of neat thing about humpbacks is when humpback whales call, they're actually calling quietly. So that tells us something like why would an animal that can be heard for 10, 20, 30 miles away choose to whisper? And we take this research in Southeast Alaska where we measured, how loud a humpback call was, because we wanted to say how far away we could hear it. And, and the answer was that these animals weren't calling loudly at all, which is an indication that when they make those sounds, they're not advertising something, but they are communicating. So they're limiting their range of communication. So we can pretty safely say that you can hear humpback calls from at least five miles away, and, and likely up to 10 or 15 miles away, but it really depends on how the whale is behaving. And then of course, that brings us back to noise. Because if, if a boat is passing by that communication range just diminishes, it can go from 15 miles to 15 meters in a matter of moments. The louder your background noises, the less you hear the sound that you're interested in, which means that when boats pass by the whales can't hear each other and we can't hear them either.
AMY: There, there are so many different ways that human activity is impacting the ocean. You know, ocean acidification and plastic pollution, among all the different impacts. How would you rank the noise problem in, in terms from a whale perspective? Like, is it the most harmful thing we're doing to them? How much of an impact are we having through our, through the noise we're adding?
MICHELLE: Is it the most harmful thing we're doing? I think that there is a real danger in ranking threats. Sure, I could say I think noise is the biggest problem. And then we would stop caring about ocean acidification or I could say entanglement is a bigger problem. And then we focus all of our efforts there. The truth of the matter is all of these are cumulative threats. Noise creates behavioral shifts. It prevents normal life function from happening. It likely creates stress, but all of those things are exacerbated by shortages in food that are associated with climate change. All of those things are exacerbated by the likelihood of ship strikes. If an animal is disoriented because it can't hear, it's likely to get hit by a boat. That's a cumulative problem. If an animal changes its normal distribution patterns, because the distribution of its prey have changed and it's having a hard time finding food and its new area that it has to move into in order to find this forage fish is a shipping lane, now not only is it food stressed, but it's stressed by noise, it's reduced ability to communicate that. And now it's likely to get hit by a boat.
AMY: Yeah, I hear you. That's a great, that's a great framing of it that, to understand that really, to try to just hone in on one problem and ignore others is it's not going to give us the true nature of the problem
MICHELLE: Yeah it's really, it's really important that we think about ocean conservation holistically and that we, that we think about it from an integrated perspective that our goal can't be to sort of say, we're going to solve this one problem: that we have to do is protect an ecosystem. And even though I have a deep love for humpback whales, they're not the only species that's at risk because of ocean noise or because of ocean acidification. And the loss of whales would throw our ecosystem out of balance. And similarly, a loss of prey species will throw our ecosystem out of balance. No one single species encompasses the health of the ocean. They interact with each other. And similarly, we think that what happens in the ocean is isolated, but what happens in the ocean changes what happens to us on land. This is a little morbid, but there's a lot of really interesting research done on carbon sequestration inside the body of whales. Whales are an enormous animal and worldwide they encompass a lot of physical mass. Before industrial whaling, when whales would die, they would sink to the bottom of the ocean and that carbon would be sequestered and it would stay out of the atmosphere. It would sink to the bottom of the ocean and it would stay there for a long time until the carbon cycle resurfaced it. During the industrial revolution, when we were really heavily hunting whales worldwide, we took massive amounts of carbon that naturally should have sunk to the bottom of the ocean and stayed there and we extracted oil from it and then we burned it. The first, the start of the tipping of what we now know as the anthropocene where the human footprint on ecology became noticeable in the geologic record, so much of that started with the body of whales. It was the first widespread oil that we used for light or lubrication or fuel on this planet. All of that started with the burning of the body of whales. And so in a lot of ways, what has become our current climate crisis began when, when we began extracting this massive living carbon source that should have sunk. And so should we save whales for their own, right? Oh, absolutely. We should. We should. We should protect whales for their intrinsic value. We should have a quiet ocean because a quiet ocean is something of value whether we experience it or not. But if you need more of a motivation for why it is, we should protect the ocean, we should protect the ocean because the ocean is, is how the world naturally moderates its climate. None of these ecological processes occur in a vacuum. The conservation of a species is the conservation of a planet. And the conservation of a planet saves us all. So, save the whales and save yourself and, and in one fell swoop.
AMY: That's fascinating. I had not thought about the, the whales and the carbon connection. Just to bring us back to sound. What effects do the noises that we're making have on whales specifically? Do we know what effects we’re making?
MICHELLE: Yes. We know a lot about how noise impacts whales. So there are three primary shifts that we see that whales will exhibit in, in the presence of anthropogenic noise of man made noise. When boats approach whales, whales dive longer and they move away and that might seem obvious and that might seem small, but it means that we have the potential to displace these animals. And when we follow that up, what we see is that in addition to moving away and diving longer, that when there are a lot of vessels in the area, there is evidence that humpback whales in particular will reduce their foraging effort. And that of course could have massive fitness implications. And then the work that I've done in southeast Alaska and elsewhere and other folks have done around the world also shows us that when the ocean gets noisy, humpback whales are doing their best to adapt, that they are trying to continue to be heard above the noise. And what that means is that when the ocean gets noisy with vessel noise, humpback whales will call louder, that they will increase the loudness of their calls so that they can be detected. But on the flip side of that, as the ocean gets filled with, with man made noise, humpback whales will also start to call less. That they actually, at some point, will wait until the noise has passed or where it's not worth it to make those sounds. And so what we found is that there's about a 30% reduction in the probability of a humpback whale producing a sound if the noise in the environment is associated with a man made source. If it was just rainy, rain makes a lot of noise. Rain and wind are noisy, but a humpback whale is much more likely to continue calling if the noise source is a storm or if the noise source is a harbor seal than it is, if the source is, is from the boat. So they'll call louder, but they call less, they'll move away, and they reduce their foraging effort. That's what humpback whales do when it gets noisy, but there are plenty of examples and other whales that we haven't been able to test yet in humpbacks that demonstrate that there's also a loss of social interaction associated with noise, and that there's a potential increase in stress associated with noise. There's a really extraordinary study that that is very timely to reference right now where after 9/11, we closed down the eastern seaboard for three days, and there was a group of researchers who had hydrophones in the water there and they were listening and then they were also going out and they were studying North Atlantic right whales. And they were looking at stress in North Atlantic right whales. And so for several years, they had been out on the water collecting, right. Well feces and analyzing it for stress hormones. And then they were broadly associating this with noise in the region. There was a significant drop in ocean noise associated with 9/11 for three days, the Atlantic coast went quiet. There was also a significant drop in right whale stress during that time period.
AMY: Fascinating
MICHELLE: Yeah, and that's a lot of evidence that when you reduce ocean noise, when you take boats out of the water, that stress goes down. It's correlation, you know, there, there are other things, but that’s some pretty strong evidence. And we're in another moment like that right now.
AMY: Yeah, yeah. Because of the coronavirus pandemic, things have gotten much, much quieter in the oceans. Do we know how much quieter and do we know how, or if it's affecting the whales?
MICHELLE: We don't know how much quieter yet, but we will. We definitely know it's quieter. Shipping is down. Travel is down. What that means is that the port of Miami is quieter than it has likely been in years. That means in Southeast Alaska, those humpback whales that I talked about in 1972, they are experiencing the first cruise ship free summer in 50 years.
AMY: And do you have hydrophones in the, in the water there?
MICHELLE: Yes, we do. I have a colleague in Glacier Bay National park. She has a hydrophone in the water and that one is recording. And then in June of this year, we are putting another out in Juneau, which is a tourism center in Southeast Alaska. It's the whale watching capital of Alaska. And we're going to put a hydrophone right in the center of those waters and go listen to the whales, and then we're going to put another hydrophone out in Glacier Bay, right in the path of where the cruise ships would typically go. But in this year, because there are no cruise ships, we expect it to sound very, very different.
AMY: What's your working hypothesis? What do you think you're going to hear?
MICHELLE: What I think we're going to hear is, I mean, for a start, I feel quite confident that the ocean is going to be significantly quieter in June of 2020 than it was in June of 2019. I am very certain of that as we, as we have fewer boats on the water. What I anticipate hearing from the humpbacks is actually a different sort of conversation. Because boats make a lot of noise. They limit the complexity of the conversation. I'll make an analogy here. If you are having a conversation at a rock concert, you're going to talk loudly and use very simple language in order to get your point across. But if you're sitting next to somebody on your couch, cuddled up under a blanket, you can have a long and elaborate conversation filled with nuance without interruption. So what I hypothesize is that what we're going to hear from the whales this summer, our conversations that perhaps we've never heard before, that the level of complexity in the acoustic interactions that we hear is going to be higher than it has been in the past. What I think is going to happen is that the quality of the conversation is going to change as we open up the acoustic space. And I think that this can only happen because it is such a protracted period of silence.
AMY: Yeah.
MICHELLE: It's not like someone just really quickly turned off the noise and then turned it back on again, it's that these animals will have the chance to adapt to this period of silence on an ecologically relevant scale. Remember, when we think about humpbacks, we have to change how we perceive scale. So three days in the life of a humpback whale is monumental, but two or three months of silence is enough to really start to see these animals shifting their behavior in a meaningful way.
AMY: So as awful as this pandemic is, and as much suffering as it's causing, from your perspective, in terms of what you're trying to study, this is kind of a once in a lifetime opportunity for you to learn something and to gather some data that you would probably never have gotten the chance to gather otherwise.
MICHELLE: Absolutely. I mean, it, it is completely unethical to cultivate this situation. I could never ask southeast Alaska to shut the cruise ships down for an entire summer. The economic ramifications of this pandemic are enormous and, and there are communities which are suffering and are going to suffer for a long time. And my heart goes out to them. And I want them to be able to get back on the water, to interact with these animals. But if we can't find at least some gratitude for the fact that amidst all of our human suffering, that there is, you know, perhaps this moment of relief for our oceans. I mean, that, that it seems essential. There's not going to be another opportunity for this in, in, in my lifetime, in my career—I hope. I absolutely hope that we don't go through this again. But as a result, it is critical that during this time, that we find a way to listen. And that's exactly what we're doing right now is all of us are hunkered down, sitting in our living rooms, waiting patiently so that when this whole thing blows over and we can get back out on the water to recover these instruments, that we can take the time to listen to what the ocean was doing when, when we were all at home.
AMY: Hm. As somebody who also works in sound, I have to say, I just hope your mics are working. I hope you don't have any technological issues. I'm like nervous for them. Now. I want to go like, wait, testing, testing, are you picking this up?
MICHELLE: We are doing everything we can. We know for sure that one of our hydrophones is working and the other ones I am going to trust the technology and, and also cross my fingers.
AMY: Well, my last question for you, it just has to do with the future. Do you think that this is a solvable problem? Can we have a globally interconnected human society without polluting the acoustic environment so terribly for whales and all the other creatures that are depending on, on a quieter world?
MICHELLE: You know, I'm going to tell you about a sign I saw on a shop here in Ithaca. I thought this was really inspiring. The shop was closed, and it said, “look how quickly the world changed. You did that. We did that. We can do anything.” This was probably the most rapid shift in human behavior that we have seen in a millennia. If we can shut down all of society over a pandemic, I am very confident that there is nothing we can't do. We can make good decisions and we can make generous decisions and we can make kind decisions, and we can make hard decisions. I have a lot of hope that having this opportunity to listen is going to enable us to give voice to the ocean again and give voice to the ocean in a way that we've never been able to do it before. So, yes, I think that we can change our behavior. I think that we can change how we interact with each other. And I think that we can change how we interact with this world.
AMY: Well, Michelle Fournet, it's been an absolute pleasure to speak with you. Thank you so much for your work and for taking the time to talk with me about it. I hope to meet you in real life and get to listen to some of your, your new data as it comes in at some point.
MICHELLE: Absolutely. I would love that. And, this has been a real pleasure. Thank you so much for reaching out.
AMY: All of the whale sounds you heard in this episode came to us from Michelle; thanks to her for that gift. Thanks also to the Park Foundation, Montana Public Radio, the International Women’s Media Foundation’s Howard G. Buffett Fund for Women Journalists, and the many listeners who support our work at threshold podcast dot org slash donate.
The Threshold team includes Taliah Farnsworth, Eva Kalea, Nick Mott, Caysi Simpson and Angela Swatek, with help from Caroline Kurtz, Dan Carreno, Hana Carey, Kara Cromwell, Katie DeFusco and Matt Herlihy. Our music is by Travis Yost.