Episode 5: Music for Motion - "Why Whales Sing" with Dr. Eduardo Mercado III

Welcome to Wild Resonance, a podcast exploring bioacoustics and the sounds of the natural world.

In this fifth episode, host Stephen Griesgraber talks with Dr. Eduardo Mercado III about his book "Why Whales Sing." Published in November 2025, the book challenges the current understanding of whale songs. Broadly believed to be an aural "peacock tail" and courtship strategy, Eduardo proposes that whale song is a form of echolocation humpbacks use as a sonar system to search for one another.

Dr. Mercado is a Professor of Psychology at SUNY Buffalo, where he has also served as the Director of the Center for Cognitive Science. Mercado strives to progress cognitive theory by quantifying behavior in novel ways, collecting evidence that directly challenges current assumptions about how minds think. While he has published on the singing behavior of whales, his research has also focused on the cognitive ability of dolphins and children with ASD.

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Dr. Mercado's website : https://www.eduardomercado.com/

Buy his book!
JHU Press - https://www.press.jhu.edu/books/title/53709/why-whales-sing
Amazon - https://www.amazon.com/Why-Whales-Sing-Eduardo-Mercado/dp/1421452898
Barnes and Noble - https://www.barnesandnoble.com/w/why-whales-sing-eduardo-mercado-iii/1146939309?ean=9781421452890
Bookshop.org - https://bookshop.org/p/books/why-whales-sing-eduardo-mercado/aa6bb7b038ceb610?ean=9781421452890

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Transcript

Cold Open and Intro

SPEAKER_05 0:00

So the consensus was that for sure the humpback wells, when they were singing, were basically performing a mating display, and it's the males basically peacocking for the females. In addition, the consensus then and now is that no bathing wheels equate at all in any context, much less in a singing context. So it's like, number one, no bathing wheels equate. And number two, if they were equating, it definitely wouldn't be singing. So that's, I would say, still the current belief right now. And so that's partly why I wasn't gonna mention this to other people, because they'd be like, Are you like, have you not read a paper? Like everybody knows baleen wells don't equate, and definitely not singing is not equlocation. So what are you even talking about?

SPEAKER_00 0:46

Hello, and welcome to Wild Resonance, a show where we explore sounds of the natural world through conversations with scientists, musicians, artists, writers, and all manner of sonic explorers. I'm your host, Stephen Griesgraber, and today I'm very excited to have with me in the studio Dr. Eduardo Mercado III. Dr. Mercado is a behavioral neuroscientist with a background in computer engineering and cognitive science, and he has a new book about Why Whales Sing, which is published by Johns Hopkins University Press. And in it he uh explores the possibility that humpback whale vocalizations are used for echolocation, an idea that somewhat uh challenges the more broadly accepted idea of humpback whale song as a courtship ritual. Uh so Dr. Mercado, thank you for being here. Thanks for having me. So I'm really excited about this book. I just read it and um it's uh I think it's quite brilliant and quite interesting. Uh

What Is Echolocation?

SPEAKER_00 1:43

I want to start at the very, very beginning. For those of uh those people watching who aren't familiar, could you just tell us what echolocation is?

SPEAKER_05 1:51

So echolocation comes in many forms, depending on which species is doing it, but the gist of it is that the animal or person puts out sounds, the sounds go into the environment and hit things and bounce back, and then their brain takes those echoes that are coming from the world and turns them into some kind of image.

SPEAKER_00 2:07

Aaron Powell What animals are known to echolocate?

SPEAKER_05 2:10

Um so the ones that have been studied the most are bats, various species, dolphins, a few other cetaceans. So cetaceans would be wells, dolphins, porpoises. Most studies of eclipse and cetaceans are of dolphins. And there are some birds that are known to eclocate as well.

SPEAKER_00 2:25

And so in the case of bats, most of us imagine them as nocturnal animals, spending time in c habitats, being caves, dark places. How about dolphins? Like, why do why do animals need to do this?

SPEAKER_05 2:37

Yeah, so most of the animals that are known to equate are doing it in situations where they can't see the things they need to see. So, I mean, you might think of dolphins in the ocean being able to see like a snorkeler or a scuba diver, but they're also operating at night and in conditions where it's the water's not quite as clear as you might see when you're snorkeling. And so they're also dealing with the fact that they can't see things around that that they need to. Um so I would say all the animals that have evolved equilibrium and use it like daily or nightly, it's because they can't see the things that they need to be able to monitor.

SPEAKER_00 3:11

Okay. Are they using it for specific purposes or are they using it sort of as broadly and generally as humans use sight? I mean, are they looking for specific things? Are they surveying their entire environment? Both?

SPEAKER_05 3:24

In the case of dolphins and bats, they're using it most often, at least the ones that have been cases that have been studied, are like a foraging context. So they're trying to find prey to eat. But they will use it on each other and when they're monitoring the movements because they have to be able to tell where uh individuals are moving without being able to see them. And so that would be more of a social context where they're using the sounds. And it's not like to answer your question about is it like vision? It's not, it's much more um, I would say, voluntary. There have been experiments where they've put blindfolded a dolphin and put fish in the tank with it to see how it will use its echolocation to find the fish, and the dolphin just swims around quietly and then grabs the fish. So it's like they don't need it in the same way we need vision, but they use it as sort of like almost like it's more like a hand gripping kind of like I'll reach out and touch it if I feel like I would get the information I need that way. But it's much less automatic compared to vision, I would say. Okay.

SPEAKER_00 4:18

Interesting.

Mercado's Journey: Computer Engineering to Cetaceans

SPEAKER_00 4:19

And so so your story. You have a background in computer engineering, and if I remember correctly from the book, that's what you studied as an undergraduate, right? So what's the what's the path from computer engineering to uh citation studies and echolocation?

SPEAKER_05 4:34

Right, it's definitely not a path that anybody would plan in advance. Um so yeah, I did my undergraduate work in uh computer engineering, electrical engineering, computer science, and I worked at IBM in a hardware design lab. I was I was a cooperative student, which means I I would work a semester and then go to school a semester and then work a semester the whole time I was in school. And when I was working, actually I had much more time to kind of think about things that weren't just homework. And in that time period, I was trying to understand like what are the alternatives to use for computer design. There's a very kind of standard design that applies to all computers that exist in the sort of commercial world. Um, and it's a very serial processing kind of mode of dealing with information, but brains seem to operate in a more parallel universe where they're processing everything at the same time. And so I was curious about how that would work in a computer context. And so indirectly, I started looking at sort of brains and how do they do it, and from that I kind of randomly encountered dolphin brains and realized that people didn't have a clue how they were using them. And so at some point I realized I was more interested in the sort of biological aspect than the hardware aspect, and so I kind of had this epiphany of like I don't want to build machines until I understand this other way of doing computing.

SPEAKER_00 5:50

Interesting. And so so where did that lead you? You you you have this new interest in in dolphin brains. Where and how did you decide to investigate that?

SPEAKER_05 5:58

Yeah, that was a little bit tricky. I I once I realized that I was kind of more intrinsically interested in this uh, you know, unique set of mammals and how they were able to use their brains in ways that were similar to what primates were doing, at least from the experiments, I kind of searched around all over the world to see what labs were actually studying complex information processing by uh cetaceans. And the biggest concentration of researchers doing that at the time was in Honolulu at the University of Hawaii. And so I applied there to a lab that was one of the top labs at the time, somehow convinced them that I could come in as an engineer and help them with this kind of project, and that was my start. So I was kind of tunnel vision of like this is what I'm gonna do, where I need to go to do it. There's the place right there. So unfortunately, I was forced to go to Hawaii to work on this.

SPEAKER_00 6:45

At one point when you're doing um dolphin research, you had an idea that you wanted to try to see if dolphins could sort of process or understand number concepts. And and then the idea was kind of shot down as being a little too far-fetched. I'm just curious, what did you have in mind? And do you think they could have done it? Or do you now know that they could have?

SPEAKER_05 7:04

Um, so I was basing it on studies that have been done with chimpanzees and the way they can sort of recognize they can essentially label numbers independent of what the thing being numbered is. So that's kind of interesting about number concepts, is that they can be applied to like any sets of objects, even to sounds. You could hear three sounds and know it's still three. And so it's not specific to a perceptual modality. And I thought it'd be interesting because dolphins are not operating in the same domain as chimpanzees, you know, they don't have hands, they're not manipulating things in the same way. It would be interesting to see like what their kind of concept of quantity would be. I'm sure they could have done it. I was not able to convince the main investigator that was true, but um there have been some studies since then that have established kind of the basics of what I wanted to establish. So they've kind of shown that they do can't form number concepts in a way that a primate might.

SPEAKER_00 7:52

Was that Lou Herman or Neil Fraser?

SPEAKER_05 7:54

Which one of your Yeah, Lou Herman, he ran a lab called Kuala Basin Marine Memo Laboratory, and he's the one that trained dolphins to interpret sign language as being instructions.

SPEAKER_00 8:03

Right. Oh, okay.

SPEAKER_05 8:04

Wow. Yeah, so I was giving dolphins instructions with sign language for like five years.

SPEAKER_00 8:09

And then okay, so now then and then how did you get to the humpbacks?

SPEAKER_05 8:12

Yeah, that's an interesting random convergence. So I I definitely was not interested in studying any large baleen welds when I went to Hawaii. I was very focused on dolphins as being the ones you could actually do experiments with and kind of really push them. And what happened was that Lou Herman had gotten a grant with IBM to try to do some acoustic analysis of humpback well songs. Um, and so they had this money, but then when they got the money, that there was nobody in his lab that was actually working on that. And so they kind of had the IBM engineers, but nobody for them to work with. And so he came to me because I had worked at IBM, um, and he was like, Could you help with this? Uh and I was like, I probably could because I know the code and things like that, but I don't know anything about humpback wells or singing. And he's like, Better somebody than nobody. And he offered to pay me. I was like, Okay, you're paying me, yeah, I definitely can do it. And so I ended up working with his um IBM engineers to try to analyze songs with none of us really having any clue about what we were doing at the beginning. And so I was very reliant on other people and just reading the literature and trying to get to speed really quickly. And I had no intrinsic interest in it as a sort of scientific question. It was more of like, they want me to do this, I can do it, so I'll I'll focus on it.

SPEAKER_00 9:21

Um and if we could just as a uh quick aside, the distinction between whale types. So dolphins and you know, beluga's, etc., versus humpbacks, and they're baleen versus tooth, right? What's right.

SPEAKER_05 9:34

So there's two main classes, the baleen whales are the really large ones that you you know, the the blue the blue whale um is kind of the I guess poster child for that group of whales. And they're called balan whales because they don't have teeth, they have these kind of like almost like fingernail-ish like things that they use to filter fish out when they're feeding, versus the tooth whales is the other main category. Most of them are smaller, some are large, like orcas, uh sperm whales. And so they're considered to be very different, and they are very different in terms of like the way they forage, their social lives, the way they use sound. And I would say they're studied almost independently. There's very few people that study both, so it was kind of random to happen to be in the one of the few labs that studied both tooth wells and balanws.

SPEAKER_00 10:15

And so, what did you find with when when you were going through these uh data sets or analyzing these humpback songs?

SPEAKER_05 10:20

Right. So the task that I was given and IBM engineers was make us a library of sounds that wells make that they combine together when they're singing, basically like an alphabet of well sounds. And so our goal was to kind of just catalog this alphabet of well sounds, and then we'd give it back to them, and they would use it to transcribe the songs like you might, phonemes and speech. And so I was working on that, and it worked out really well for the first year of data analyze. We had this alphabet that was pretty consistently classifying the sounds, and then I went to the next year of data, and it was working okay, but there were some new sounds there, and then there were some that were gone. And then I went to the next year, I'm like, wait a minute, this is happening again. And by the time I get like six years in, the original alphabet didn't apply to any of the sounds anymore. Wow. And I was like, this is not good because if you need a new alphabet every five years, how are they ever gonna try and you'd have to make one every single year, basically, and you couldn't compare it to ones before. And so I was kind of getting nervous because I was like, I am not gonna be able to do this task that is just not the data's not gonna work out, and so it ended up being a task that made me learn a lot about the flexibility that the wells were deploying when they made these sounds, like they weren't just making the same sounds over and over and over again, they were definitely varying them. Um, but it was bad for me personally, in the sense of like, I'm gonna fail on my first scientific task that I'm being paid for, and it's not gonna go well because of that.

SPEAKER_00 11:38

So, you know, you have you have um this background in computer science and working with numbers and data, but you're in this lab with people who have a lot of background with whales, right? And so when you were having these observations and these you know challenges, what were they saying? What kind of feedback were you getting to explain all of these changes?

SPEAKER_05 11:58

And um, most of the feedback was you're probably doing something wrong. You're you're you're analyzing in some weird way that's not the right way to do it, that they shouldn't be doing this. There no one's reported that they're doing this, so what why are you saying they are doing it? And I'll and I was kind of like, maybe I am doing it wrong, but all I have is the recordings that I you you know that I have available to me, and then I'm looking right at them. So it's not like I'm making it up. I can show you how they're different. I didn't really understand myself why no one else had reported it in the literature because it seemed pretty I I think partly it was because they were not focusing on individual sounds, they were focusing on these patterns in the sounds, and so they knew the patterns were changing, but they didn't really focus on the sounds because they they already saw changes in the patterns themselves. And so I think there was sort of this assumption that, well, surely they're using the same sounds because every other mammal on the planet is doing that. And I was like, yeah, that makes sense to me, but they're not doing that. Okay. And I I think that's what actually got me interested in it scientifically, because I was like, why are they making my heart life hard? I you should be doing what all the other mammals are doing. You shouldn't be making this like a problem. This should not be the tricky part of this project. So so and and IBM, then were they interested in these results, or what I feel like I the people that I worked with at IBM were they were great uh engineers and they were really uh spent a lot of time on it, but they didn't really care about the science part. It was more of like a technical thing of like I gotta make an algorithm that can sort these things into piles, and and that's basically what they focused on was like making software that could do that. And then I guess I was the part that was supposed to be telling them or steering them towards the scientifically relevant piles. So that made it be all on me essentially because they were just like, I'm just doing what he's telling us to.

SPEAKER_00 13:40

But and and then at the same time you're you're catching the marine mammal bug because now you're gonna you're shifting from computer science to to really be interested in these animals, right?

SPEAKER_05 13:51

I I mean it's kind of interesting because I went there to do dolphin work and I was doing dolphin work in parallel with this, but I was actually seeing more, I guess, interesting things in the in the acoustics analysis than I was in the behavioral part. Maybe not more, but at least more unique. Um and so yeah, I definitely, having been in the lab, the more I was there, the more I got into being marine mammal focused. That was why I went there. But I also kind of expanded my original thinking to like maybe it's not just what I can teach them to do that would be interesting, but maybe what they're already doing without being taught would also be kind of interesting

An Epiphany! What Whale Song Might Do

SPEAKER_05 14:23

to understand.

SPEAKER_00 14:24

You have an epiphany about what these sounds might be.

SPEAKER_05 14:27

Yeah, I was very confused. Um, the more I studied them, the more confused I got. And it mainly was because it made no sense to me that they would be changing their sounds, just like it made no sense to somebody else, and I was like, this, yeah, they should not be doing this. I was looking for other animals that were do doing it, and I wasn't seeing them singing and changing their sounds this way. It was only when I was reading about dolphin echolocation and this and discovered this experiment that it looked at beluugas specifically echolocating, and they had kind of found that surprisingly when the belugas were echolocating at things that are very far away from them, like a football field or more away from them, that they would switch from their normal echolocation mode, which is just put out clicks, to this kind of very machine gun-like bursts of sound. So it'd be like, meh, meh. It seemed like it shouldn't work for echolocation because the sounds were all just too close together. But that's what the belugas chose it naturally did when you put things really far away. And I was like, why, why are they doing that? So it's yet another thing of I don't understand why they're doing that. Um, and and just in thinking about that, like they are doing it, even though I don't know why. It's like maybe it's because when things are really far away from you, the normal equilibriation doesn't cut it anymore. You've got to do something different. That's probably why they're doing it, because I need to do it to be able to actually detect things really far away. And then in thinking about that, I was like, okay, well, that's really far away, but what if it was really far away? What would equalication be like then? And then started wondering, could the sounds that the wells are making actually be used for equalcation, even though I can hear them and they're not clicks? And that was sort of the epiphany of like maybe it is sound, it can bounce off of things. And so it kind of sent me off to think about like, is that how would this even be possible for a singing well to be doing this kind of I would say like extreme beluga behavior to try to detect things that are like miles away from it? I would I wouldn't say it's an it was an epiphany and this is like aha, I figured out it's more like maybe this could be something, but this seems like really weird, and I don't understand how it would work.

SPEAKER_02 16:20

Yeah.

SPEAKER_05 16:21

But at least changed my way of thinking about it, and I started exploring. And then I discovered that, yeah, the only mammals that really change their sounds so radically over time are bats. When they're echlocating, I was like, oh. Well, that could be uh another mammal that's doing something similar, and so it's kind of like a chain reaction of me discovering things that I wouldn't have thought to look for otherwise.

SPEAKER_00 16:41

Just out of curiosity, how many different species of bats echolocate?

SPEAKER_05 16:46

That's a good question. Uh most people assume that all of them echolocate, but only a small subset of it have been studied to show it. Initially it was shown with one species and then it kind of spread out from there. I'm not sure it's like the exact number. There's probably about a hundred that have been studied, either in the wild or in much fewer in laboratories. Okay. But they hear the other species making similar sounds in similar contexts, and they just say probably they're echlocating because all the other ones were.

SPEAKER_00 17:09

And so among the different species of bats that echo locate, um, is there quite a range in the types of sounds they make?

SPEAKER_05 17:18

Yeah, I mean, they're they're mostly ultrasonic, so we can't hear them, so we're not being exposed to the range, you know, in the in the real real world.

SPEAKER_00 17:25

We can perceive it, but it could still be significantly different. Yeah, yeah.

SPEAKER_05 17:28

So if you analyze the acoustics, you can see the differences. And there is a broad range. There's kind of two broad classes that have been identified, which correspond to essentially bats that put out sounds and wait for the echoes to come back, and bats that put out sounds almost continuously and are listening to the echoes while they're making the sounds. Those are kind of the two broad classes. And then within those classes, there's a lot of variation in terms of the way they manipulate sounds. The first bats that we're studying were doing relatively simple things in the laboratory, but they soon disc well not soon, they eventually discovered that some of these bats are putting out pretty complex sequences when they're s uh searching for prey to attack, essentially. So they're not all doing the same thing. It's in that sense it's different from the dolphins because most dolphins that ecocate or that have been described as ecocating are putting out cliques. And the cliques are not identical, but they're pretty clearly cliques. They would sound like a click if you heard them. And so in that sense, the bats are much more variable across species than the cetaceans are, at least the tooth whales.

SPEAKER_00 18:24

Right. Because it w uh um among cetaceans, uh it's a relatively small number, right? It's dolphins, it's sperm whales, beluga.

SPEAKER_05 18:32

Yeah, there's about 75 identified species of tooth wells. Only probably like I would say seven of them have been studied in a laboratory context. Okay. But again, if you hear them clicking, people just assume they're echolocating. Right. Even sperm whales. And so in that context, I would say they don't just assume that every click is a is a echolocation

Echolocation vs. Ambient Perception

SPEAKER_05 19:02

signal.

SPEAKER_00 19:02

How do scientists distinguish between echolocation and you know ambient acoustic perception? Like I at some point in your book you're you um you have a conversation with another scientist where you sort of give him an opportunity to challenge some of your ideas, and he mentions that the fact that no human would have any trouble whatsoever distinguishing between being in a bathroom versus a basketball court. Right. Like we're we even if we're not echolocating, a lot of times we have a spatial awareness that's related to you know audio information or acoustic information, feedback we're getting. Uh people who study echolocation, how do they distinguish between those two phenomena?

SPEAKER_05 19:39

It's not I wouldn't say there's like a um cutoff where you say this is definitely echolocation and this definitely hearing the acoustics of a room space. Um they're all echo processing of a of a kind. Um I would say that the things that people point to as being clearest evidence of echolocation as a way to perceive the world beyond just hearing it would be things like can they tell how far away they are from it? Are they modifying the way they make the sounds based on how far or far they are away from it? Um, in the case of like humans that echolocate using clicks, it's self-report of what they're perceiving. So they're perceiving things that other people aren't. They can't like they they hear all the things that that everybody that's not equating here, but they also can detect things that people around them are not detecting at all. So I think it's a lot about what kind of information can you show that the individual is getting from that and how precise is it.

SPEAKER_00 20:31

I see.

SPEAKER_05 20:31

Uh in the case of bats and dolphins, usually precision means like can they catch it just when they can't see anything.

SPEAKER_03 20:38

Right.

SPEAKER_05 20:38

Um and that would be the kind of evidence that would say, yeah, this alpha for sure is actively making these sounds to get the echoes back. And you can also see the timing of the echoes relative to when they're coming, when they're making the sound. So this sort of like make a sound, listen, make a sound. It's very choreographed in that sense. And in a way that's very different from right now. I'm talking and I'm in a room, but I'm not really modulating my speech based on anything that's happening in the room other than you talking to me.

SPEAKER_00 21:03

Right. You have this idea, um, and what do you do with it? Do you write it up? Do you uh discuss it with uh an advisor?

SPEAKER_05 21:12

Yeah, none of the above. So uh first off, what I did was try to like figure out what was wrong with it because I was like, surely somebody would have like already talked about this. I mean, I'm just coming into the field of brand new, and people have been studying this for like 20 years already. So I was just reading all the papers, trying to say, okay, like what's wrong with this idea? What am I missing? And I started looking at the physics of it and tried to say, like, well, there's got to be some kind of constraint that makes it not be possible that I haven't recognized yet. And through all that, I wasn't finding the thing, the smoking gun of like, oh, this is where you're wrong. But I didn't talk to my advisor about it or anybody that actually had some sense because I didn't want to. This is my you know, for just after my first year of grad school. I'm not gonna expose myself as being that clueless that that soon. But at some point I was just like, I didn't I don't know what's wrong with it. So I ended up um emailing two experts, one expert in dolphin. And one an expert in ocean acoustics. And I just said, like, here's what I'm looking at. I can't figure out what's wrong with this. Can you tell me like what I'm missing? And that was like my plea for help of like just send me right before I like lose it. But that was uh I was lucky that I had access to those experts and they were willing to respond to me because otherwise I would have been just like continuously confused, essentially. So when I did that, it was a unique scientific experience for me. I was very nervous to be exposing myself to them, but at least I was coming as like a student, like teach me, and so I didn't feel as quite as nervous about it. Um but they both replied to my email, and one of them said, like, that idea is like nonsense, like you think it is, and here's why. They can't possibly hear the echoes, they're too quiet. Um, and I was like, Oh, that makes sense. Uh and then the other one wrote back and said, like, oh no, that definitely makes sense. There, they could certainly be doing that. And so they had the exact opposite uh response to my initial emails, and I was like, huh. So I'm not the only one that's confused, apparently, because there's not a consensus about what's really going on in this scenario. But it I think that lack of consensus was enough to make me think, like, oh, it's a it is a question, it's not just something obvious I'm missing. There's some kind of subtlety to it that I haven't really appreciated until now that these two experts have kind of had the opposite take on it. Also the fact that at least one expert was like, oh yeah, that's that could work gave me a little bit of more motivation to keep on thinking about it because I was like, oh, okay, so this is worth thinking about.

SPEAKER_00 23:24

Because you know, what what was at that time what was consensus, and maybe still now?

SPEAKER_05 23:30

Oh yeah. So the consensus was that for sure the humpback wells, when they were singing, were basically performing a mating display, and it's the males basically peacocking for the females. In addition, the consensus then and now is that no bathing whales equate at all in any context, much less in a singing context. So it's like number one, no bathing whales equlocate. And number two, if they were equlocating, it definitely wouldn't be singing. So that's I would say still the current belief right now. And so that's partly why I wasn't gonna mention this to other people, because they'd be like, Are you like, have you not read a paper? Like everybody knows baleen whales don't elocate, and definitely not singing is not echlocation. So what are you even talking about?

SPEAKER_00 24:11

But

Holes in Popular Observation

SPEAKER_00 24:12

I I feel like there are some, you know, potential holes in that thinking, right? For instance, um, females haven't been observed showing particular interest in in male song, humpback whale song, right? And you know, what are some of the other sort of counterarguments that at least uh s sort of allow us to um imagine that we don't have enough information to conclusively say that?

SPEAKER_05 24:35

Right, yeah. So the behavior is the I think a lot of people feel like the behavior should make it clear exactly what's happening. Um and so in the early studies of singing whales, they did things like watch to see if the females approached the males, they never saw it. And then they started broadcasting, and they thought maybe I'm just not at the right place at the right time, so they started broadcasting playbacks of recordings of singing whales, and the females never came to it. So they were all expecting the the females to kind of like a bird would maybe be seen to do. Like the the males would display, the females were like, Oh, that's pretty nice, and they would go up and then they would you know have the fun time afterwards, but they never saw it, and so they're just kind of like, Well, it's happening, but we can't see it, and we can't make it happen. It's just very mysterious. Maybe it's oh you know, they have to be in the right mood or something. I don't know. The thing I discovered when I looked at the papers that they did see things that they weren't explaining. For example, they'd see a well singing by itself, they almost always sing by themselves. About 85% of singers that have been studied have been wells that are motionless by themselves with no other wells near them. But those whales will sometimes stop singing and then rush off at high speed in some direction. And then when they finally stop swimming fast, they're with other wells. So it's clear that somehow that well figured out where those other wells were at, even though they were multiple miles away from them and intercepted them. So they're probably not just sitting there, they're actually swimming. So it somehow figured out the trajectory it needed to go to to find them. And they just like, oh well, yeah, that's singers can tell where they're at. And it's like, how? How does a singer know where to go? They have it has to be sound. That's the only possible option.

SPEAKER_00 26:04

I want to go back one second because I think you said something very significant, or at least significant to me, and and I and I want to get you to say it explicitly. Um, how many times have a male and female humpback whale been observed mating, period?

SPEAKER_05 26:21

Yeah, uh it's for from the scientific perspective, zero. There's no there's no documented instance of it happening.

SPEAKER_00 26:27

So so to say that there's consensus about uh this behavior and how it functions, but you've never no one has ever seen the end result in any capacity is it should make people humble.

SPEAKER_05 26:39

Yeah, they should be like you there's a lot of things you haven't seen. They're definitely mating.

SPEAKER_02 26:42

Right.

SPEAKER_05 26:43

But and you've been watching them for like 35 years or more. There's many more things that we haven't seen than that we have seen. Right. And it all of the studies have been done in very specific locations. So I mean the humpback whales are per migrating from like Alaska to Hawaii and back every year. All kinds of things are happening in their life that we're never have never seen.

SPEAKER_00 27:01

That's right.

SPEAKER_05 27:02

Like they've only studied them really in the tropics in any detail. So there's most of what they do we don't know.

SPEAKER_00 27:07

And then what was the reaction to you know, when you because you did finally present at some point, right?

SPEAKER_05 27:12

Yeah, well, so I I I first I presented it to my my advisor, and that was kind of a little uh ordeal in the sense of like how can I present it to him without him being like super annoyed at me. Ultimately, when I met with him and talked about it, he was kind of intrigued enough about it that he didn't just write it off. That was also encouraging to me because he obviously knew a lot about that, even more than the experts, because he said Humphrey Well specifically and singing. Um, so the fact that he wasn't like that's ridiculous. I mean, he kind of was like that's ridiculous, but at the same time, like in a way that I can't tell you why.

SPEAKER_00 27:42

Um was this Neil Frazier?

SPEAKER_05 27:44

No, this is still this is Lou Hermann Lou Herman. So the one who had first put me on this project, who had said, like, what are you doing wrong? I felt like I was he was like, You just going off the rails now. Like first you couldn't do what I told you to, and now you've got this other weirdness happening. But he couldn't poke a hole in it immediately. He was willing to have me spend time on it, and I worked with Neil Frazier, who was the expert who had sent me the email saying, like, yeah, this is possible. And we started doing simulations of ocean acoustics to see like the physics of it, because he's a physicist to see how far away could it work, what would these sounds work in specific environments where the wells were at, and we figured out they could. Um, and so at that point, I presented I submitted it for presentation at a scientific conference. I collected all the evidence that I and Neil and Lee Warman had had sort of collected over the um last uh half a year that seemed to suggest it was all physically possible and behaviorally consistent with what was happening and evolutionarily plausible based on the fact that bats were doing similar things. And so I just presented it in this relatively short talk, about 12 minutes at a conference with a lot of marine mammal experts there, as sort of the first, like, here's what I found. It was actually my first talk in a any conference. So I wasn't sure exactly what was gonna happen when I did it, other than I knew that that's how you presented your results. You went to a conference and you said it, and then people like responded to it. So that was my first sort of public presentation of like, here's this idea, it's gonna sound crazy, I know, but here's all the evidence we have so far, but you know, without any direct experiments, and it seems like it could possibly work. It's a hypothesis I think is probably worth testable. And that was the beginning of sort of the scientific uh attempt to to introduce it to a more broad range of people to think about.

SPEAKER_00 29:27

And what was the reaction?

SPEAKER_05 29:28

Did not go well. No, it was it's crazy. I so I was a grad student, and this, you know, is uh I wasn't even like halfway done with my dissertation, so I was a pretty new one. And one expert at at the end of the talk got up and started yelling at me. I mean, like, he was mad. He wasn't just like being obnoxious, he was like, I like I infuriated him by giving this talk. Um and he he was he kind of yelled at me for like two or three minutes. This is his question, and at the end of it, everybody was just like, whoa. And the audience, because I mean, he was they're like, wait for him to maybe come up to the stage and like show me I shouldn't have said anything. And so I was like, I you know, I don't know what your question is. I I presented the evidence that I have and it doesn't prove anything I'm for sure, but it definitely doesn't, it's not like blasphemy, like I didn't say that. But I said, you know, this is what it is. I I don't know what to tell you. Um and then after even after that, other people came out to me, oh, and they were also like, you know, as the most I ever see anybody respond to a talk in a sort of like defensive way or like an upset way. That's most scientists don't get upset at talks, they're just like, oh, interesting, but wrong.

SPEAKER_00 30:36

Yeah. Yeah, well, I mean, it it I it it maybe it says a lot about um you know this this specific animal because there it's it's it's an emotionally loaded topic. We think about the the Roger Paine and and Scott McVeigh paper that that kind of uh captured the popular imagination or helped to capture popular imagination about humpback whales and the move subsequent movement, and you know it it's perhaps unsurprising that even scientists would get a little bit emotionally worked up um when their their ideas about them are are challenged. Um but so if I if I remember correctly, following this presentation, um Lou was uh a little bit, you know, uh he had a negative reaction to the reaction, but Neil was excited. Right.

SPEAKER_05 31:22

So Lou, my advisor, was like he definitely seemed like he was a little bit shaken by how like of a negative response that it had provoked. And after that, he was like, This is not something I want to spend my time on. But Neil, who was not in the marine mammal field, he was a you know a physicist doing like basic acoustics. He was like, Oh, that I thought that went really well because you you know, people were interested, and that any idea that's new and and worth thinking about is gonna cause some kind of like non-happy reaction. Right. Historically, that's been the case. So that's kind of like a good sign. I was like, well, maybe it's a good sign for you, but I'm the one that's gonna yell that and advisor doesn't want me to do stuff anymore. So he was much more, it was like again, like the polar opposites. One person was like, oh, you should just definitely not go anywhere near near this, and the other's like, oh yeah, this is a you know, make you spend even more time on it.

SPEAKER_00 32:11

Uh so

Mercado's Response: Diving into Humpback Neuroscience and Culture

SPEAKER_00 32:12

what'd you do?

SPEAKER_05 32:12

I mean, basically, Neil Frazier was enough in uh involved, he actually like was willing to like fund me to study it, even though he was into geophysics and not uh remember what he thought it was worth spending time on. So he made it possible for me to spend more time collecting more data on it. I tried to publish papers on our findings from simulations and the behavioral analyses that I had done and the and the acoustic analyses of the song itself, which no one had done before, and I couldn't get any of it published when I was in grad school. So I spent I I my dissertation actually includes the the studies of Humback Wells songs instead of the dolphin studies because I spent so much time on it. It wasn't just the song part but other things as well. Um but once I was applying for things outside of grad school, I was like, I no one's gonna pay me to do anything like this. And so I just abandoned it basically, and I switched over to computational neuroscience and did a postdoc in that area. I will say that I went to neuroscience specifically because of the humpback wells, because I was trying to understand how the humpback whales brain could do this. Right. And so I became even more interested, is even in some ways even more interesting than the dolphin brain because it was doing things that even the dolphins weren't doing and no one seemed to understand even the basics of what was happening. So that's how I got into sort of studies of learning and memory. Um, this idea of like what how does a brain deal with novel events occurring? Because if the whales are changing their sounds every year, that means their brain has to be somehow dealing with that and accounting for it. And I was interested in that aspect of it.

SPEAKER_00 33:38

Yeah. Why are they doing that or why do you believe that they're doing that?

SPEAKER_05 33:42

Yeah, so I it's I'm still not entirely sure what the benefit is. Not all baleen whales do it.

SPEAKER_02 33:47

Yeah.

SPEAKER_05 33:47

Um, so I I I feel like they've kind of been forced to it by some evolutionary constraint that other baleen whales aren't dealing with. Um, and I think it's sort of the same issue as why different bats have different kinds of ecocation signals. They didn't all converge on the same kind of use of sound to generate echoes. And the reason why in bats is because they all have different habitats and prey that they're kind of specialized for. So I believe that the humpback whales have this um expanded capacity to modulate their sounds or to modify their sounds or morph their sounds over time, because something about their environmental situation is different enough that they can't make do with what other whales are doing, which are these much simpler, less variable sounds. And what I think it is, is that the humpback whales are spending so much time in these shallow water coastal regions in the tropics where the water's relatively warm and there's a big difference between the surface and deeper water that makes all the transmission of all the acoustics of it much more complex. That essentially they've responded to this environment with this because somehow, if they don't do that, it causes problems. But I don't actually know what the problem is and how they're solving it.

unknown 34:57

Okay.

SPEAKER_05 34:58

I just believe it's something to do about the environmental constraints they're facing.

SPEAKER_00 35:01

Um to go back, we we we sort of touched on this at the beginning uh when you were talking about the work you were doing for IBM trying to create this sort of uh lexicon of um humpback whale syllables or or sounds. Did you say it was about after almost about six years, it was a completely new sort of vocabulary? Yeah, that's about right. That's a fair characterization. Um and so what um because there's humpbacks all over the in the oceans, all over the world, right? Is it is it consistent? Uh is is the the variability consistent in in different regions, or um, do they all do this? Do they all do it at the same rate?

SPEAKER_05 35:38

All the ones that have been I will say that not many people study the stent the sounds in detail, so it's there's not like a lot of hard data on it. Um, but there are definitely indications from what's been published that all the wells that have been studied so far are doing it. They don't do it all at the same rate. I mean, well, so I should say they they the rate is variable in a way that's consistent across populations around the globe. But in any g in any given year, it's hard to predict whether any group will change their sounds rapidly or slowly. So in s it's gonna be the case in like in two consecutive years, there's very little change, but it can also be radically changed in that same time period. So it's not like a staircase kind of change, it's a more dynamic scenario.

SPEAKER_00 36:20

And some people believe that this change is uh based on cultural transmission, is that right? But you would disagree?

SPEAKER_05 36:27

It's kind of unclear. So the the what you're referring to is the fact that if you look at the recordings of songs of whales across years, they change the patterns they produce over time. This is what was originally studied. And the patterns are all the whales in a particular population are producing the same patterns in the same sequence. And that's what changes systematically over years that has been studied and it's thought to be culturally driven. But I haven't actually seen the people that study those patterns look at the individual sounds, so they haven't really said if the individual sounds themselves are culturally relevant or not. As a matter of fact, some of them have said that the individual sounds themselves are irrelevant, that it's only the patterns that matter. So then they're not even talking about the changes in the sounds, they're just saying it's a different pattern, and we're not even looking to see if the phonemes are the same or not. I I'm actually curious, I haven't talked to them about this, whether they think that would be cultural or not, but I guess they would probably say yes, because they believe that the wells are imitating each other every year. Um and so if they imitate the same kinds of sounds, which they would have to be to be having the same, you know, repertoire of sounds, then that would also should be cultural. Um so yeah, they they would say that something about the sounds is learned from their other individuals and therefore it's probably cultural as well.

SPEAKER_00 37:41

Right. There's a there's an sort of often cited like an anecdote about two Australian humpback populations, right? That one that that's you know, two uh you know, outlier renegades like maybe swam from from west east to west and or vice versa. I I don't remember exactly, but then you know, taught taught the the you know this novel the entire community this new novel song that everyone adopted. But I seem to recall you finding sort of comparable patterns in whale populations, you know, via recordings obviously in Puerto Rico in the 70s and then in Colombia in the 2010s and and somewhere in Hawaii. And and so you felt like that was evidence that this is probably not the result of imitation in in the ways that um that some accepted as.

SPEAKER_05 38:36

Yeah, this is another sort of accidental um I I had no interest or at least no focus on looking at cultural transmission um in what Humbek Wells songs, just because I felt other people were spending a lot of time on that and they could they had it covered. Uh, but I had seen recordings from multiple places where the wells were producing patterns that acoustically were quite similar in terms of the pitch transitions and also the timing of them. So the rhythms and the pitch, like the melodies essentially, were matching across these populations, and that and they were populations that never interacted. So, like you said, in Puerto Rico and Colombia, they're in different oceans, so they're not ever hearing each other. Um, and sometimes every like 20 or more years, so they even if they had heard each other, that would have already been gone out of the system by the time that there would be very low chance of a convergence of that level of detail where it's the same pitches, the same rhythms being sort of essentially like different musicians coming up with the same song, even having never heard each other's genre of s of music.

SPEAKER_02 39:38

Right.

SPEAKER_05 39:38

And so I just I'd seen that, but I kind of like didn't really analyze it very much because it wasn't something I was interested in. But then I randomly was analyzing songs from Hawaii and I saw one of these patterns again. I was like, oh, that's very similar to the pattern that I'd seen in Puerto Rico from like 30 years ago. I mean, I wasn't there, but I had recordings that I had analyzed. And I compared the recordings of the songs that were recorded in in the Hawaiian population, like in the two the 2000s versus these 1970 Puerto Rican wells, and discovered that all the patterns were the same with the same timing and in the same order. And this is at Pacific versus Atlantic wells. And I was like, that's not possible. They can't have culturally come up with the same timing and pitches of songs. And so I think that evidence convinced me that there's something wrong with the story. Um and then I got sucked into that because I was like, I I don't tell you, this is what I'm looking at in the data. I didn't choose for it to be this way, and I wasn't even looking for it, but that's the way it is. And so now I've got into that, somehow got sucked into that controversy as well, where I'm I'm not sure what they're learning, but it's not that because they it would be it's too much of a coincidence for them to be doing the same thing, right? Having never hurt each other.

SPEAKER_00 40:48

One of the the distinctions we we we said between tooth whales and baleen whales is that uh toothed whales are um often hunting for uh you know a single prey, right? A single animal. And baleen whales are um you know maybe lunge feeding in a big school of fish and and capturing a bunch of prey filtering out the water. And so the echolocation uh purpose in in terms of hunting with a toothed whale is very clear. It's to identify this one animal. What are what are the baleen whales doing if they're echolocating?

SPEAKER_05 41:21

Right. So I think that's one of the things I think there's like a disconnect because all of the animals that have been studied um intensively in echolocation context are uh tracking and capturing a fleeing prey uh animal. I don't think that's what the baleen whales are doing when they echolocate. I think that they're doing something closer to to like um what a raptor does when they're searching for prey on the ground. Except for they're not looking for prey, they're looking for other individuals, is what I'm assuming. Um so when a when a humpback whale is by itself and it's singing, probably its main goal, it's usually males that are doing it. Um it's probably its main goal is to be with other whales. And because whales are moving such long distances from, like I said, Alaska to Hawaii, there's not like a gathering, you know, they don't go to Honolulu to go to the Waikiki or whatever. They're all over the place, and they're they don't have like really social units that are stable. So it's kind of like one and around in the middle of nowhere trying to randomly intermeet with other wells. And so I think the main goal for them is how do I get together with other wells given that we're all kind of like randomly swinging around in this huge ocean. And so in that context, I think the echolocation is mainly serving a social function, which is how do I know where other wells are at? There's only two choices, either I hear them making sounds and then like, oh, there's one over there, or I make them make sounds by bouncing the sounds off of them. And the second one's much more efficient because I can rather than wait for every well that's within a 10 mile radius to make a sound, I can just make them all make sounds at once by putting out my sound wave and having it bounce off them. I can monitor where they're at, I can monitor where they're moving to, um, I can know I can make decisions about do I want to join those wells that are out to the north of me by five kilometers or five miles? Or do I want to go to the ones that are the south of me? So it's much more of a social, like I'd say it's like a dance club. If the dance club had a radius of like 100 square mile, you know, something like that, that's moving over time, so they're never stable in a stable spot. So I think it's much more about social dynamics and how do you m do that when you can't see each other.

Arguments Against Echolocation

SPEAKER_00 43:26

And so you know, aside from the fact that people ha often struggle to accept the possibility that they're wrong, especially when they've invested a lot into an idea, what are the arguments against this? Why did someone stand up and scream at you emotionally and say this can't possibly be the case?

SPEAKER_05 43:43

Aaron Powell Right. So the belief is that Humphre whale songs are and other whale songs are produced only by males, only when they want to breed, um, and that the females hear the songs and they judge which males to choose as potential mates based on those um. They hear. And so the whole sort of understanding of the ecology of Baleen Wells is kind of focused around this idea of the songs being a mating display. And if you say, like, maybe that's not the main purpose for it, then you're challenging the whole infrastructure for not just the people studying songs, but people studying well behavior in general. Like you're saying, like, oh, you've misunderstood what's happening, which wasn't the goal, but it kind of is interpreted that way. And so it's it's kind of suggesting that the whole framework for understanding well behavior is somehow off-kilter from the very beginning, that they're not like birds, they're doing something different, more like what a dolphin might do in some contexts. And it seems nothing like what a dolphin does. And so the arguments are like, well, it's only males, they're not doing anything like what a dolphin does when they echolocate. So I it's all nonsense, basically.

SPEAKER_00 44:49

Aaron Powell It's not universally accepted, though, that only males uh vocalize, right?

SPEAKER_05 44:56

Well, for sure, um males and female humpback whales vo make all the same sounds. It's but that's been documented. But it's the singing behavior in particular that scientists believe that only males do. For for good reasons based on the data they have. Um but I think it that was also believed for birds for a long time, too, that it was only male birds that are singing. And so I think part of it is just the lack of information that's available, plus some kind of like preconceptions about what makes sense. Right. But so I would say most people believe that both male and female baleen whales vocalize and they can make all kinds of sounds, but also most people believe that none of them echocate with those sounds, and also that if it's singing this specific kind of pattern rhythmic production, that it's only males doing it and it's only in reproductive context.

SPEAKER_00 45:43

Okay. And you did ultimately publish, and someone wanted to publish a critique of of the work that you published. And uh tell us that story and specifically what the arguments were because they got sort of more granular than just it can't be because these are courtship displays and that's it, and you know, those things are mutually exclusive, but the the critique got into some more technical aspects, right?

SPEAKER_05 46:12

Right. So I was never able to publish a paper on this idea of song being a perceptual skill, essentially. And it was only because Neil Frazier got invited to write a paper on his topics of expertise in a journal that this got published. And he he was kind of like, oh, well, let's do a paper on this, which was not something he was known for because it had never been published before. And so we we got together all the evidence that we'd had from before, um, that had been other papers that hadn't been uh published, collected into this one paper. It was very hard to get it published even then, even though it was invited because people were like very anti the idea. Um, and but it did get published amazingly. I didn't think it would actually ever happen. And then you remember those two people that I sent emails to initially, the uh the one that had said it's not possible wrote to me as like, I don't know why you're publishing this, you're this is not possible. So it's kind of like continuing the original theme, and and I said, if you believe that, then you should publish it. And so we actually invited the attack so that it would be in print, so that it wouldn't just people people like you know, in in dark tunnels saying, like, oh, it's this nonsense because that's like just put it in print and then we'll see. And they did. So these acousticians got together all the ones who had been sort of anti-the idea, and they they wrote a rebuttal to our original paper, which was exactly what I wanted to happen. Um, although I didn't like getting the way they kind of framed it to make me seem like I was clueless. But um, but at least it was there. So I then we could uh and it was all very technical, it's about acoustics, the physics of it, partly the physics, partly the perceptual part of like what can brains do. Um but it laid out all the issues that could be uh could be against it in a in a sort of like very specific format that we could keep we could respond to and say, like, you're assuming this, that's not known. Maybe it's true, maybe it's not, but you have to kind of measure that before you say it as a fact. Or you're assumpted you're assuming this, but that's not the case because you if you look at the specific things that the whales are doing, that's not it's not the way you're describing it. So it made it much more of a public display. Interestingly, though, I feel like the you were mentioning this it was more precise. I think a lot of people didn't really understand the precise parts of the physics and aspects, and all they saw was that a bunch of famous experts said, no, it's not that. And then that that's what they keyed in on. So it ended up being like, I I think now many people would say, like, oh, they already showed you a wrong back then. It's like, mm-hmm, actually not.

SPEAKER_00 48:42

Well, I think one of the things that's interesting to me is it seems to me that uh to a certain extent, the the criticism and and your interpretation of the same information, uh you just you just arrive at different ends, but in sort of agreement um with some of those basic principles of what's happening. And b and the reason I say that is that um the critique, the rebuttal talks basically says there's way too much distortion. Like you there's there's too much, it's too noisy a place. The distortion makes it such that you would never be able to hear these echoes in any meaningful way that would give you the information that you need to to navigate or identify objects or whatever. And you're saying you uh as if I recall, you're saying the distortion is actually what gives more information that allows the animal to uh to sort of better survey their surroundings or um you know simply have more information to work with. So it's like you're saying the same thing, it just uh it takes you to a different end. And and you you mentioned the raptors because I think you make a really interesting point at the at the end of the book when you get into the brain science and stuff and saying that listen, a lot of this stuff you know can't just be measured by looking at a you know a spectrogram or just listening, because we're talking about the way that the brain is working, right? And the the operations that a raptor is going through visually to you know identify prey like extremely you know great distances, small things. The similar brain processes might be happening in in these humpbacks, right? But that's not something that you're gonna read on a graph or uh you know or hear just by listening to these syllables. It's almost exciting to me that these people who are competing actually have some compatible ideas. It's just a matter of what you do with them.

SPEAKER_05 50:25

Yeah, I mean I think it's so I try to like emphasize that when I get to these arguments, that yeah, it's extremely it's an extremely complex process of pulling out information from songs independent of whether they're echocating or not. So imagine you're a female and you're out in the ocean and you're hearing five other males singing these songs at the same time, and you've got to somehow pull those things apart even after they become distorted after being after traveling, and plus the animals changing the sounds over time, so you can't use what you did last year. You've got to interpret it a new way. So it's not an easy problem for a it's like if you were in a party and you're trying to listen to five conversations at the same time and then decide which male is the one you should go out with, that's not a trivial problem. And in many ways, it's harder than if you were just attending to your own voice and the way people responded to it. So I think it's the same issues, and I'm I think my story is like you really need to know what the brain's doing because you don't know who has the hard problem. Is it the female that has the hard problem trying to decide which male is the best from all this garbled, distorted song? Or is it the male trying to solve the problem based on these echoes that, yeah, they're all buried together in a way that humans can't deal with, and probably even the US Navy can't deal with it. Um, but they've been around 10 million years, so maybe they have to get their brain has maybe come up with ways to deal with it. And so if you don't understand what the brain's doing in this context, you're never gonna understand what's happening behaviorally or perceptually or anything else. So I yeah, I would say that all the important parts of what's going on in this scenario are all hidden from us. Um you can't just look at the sounds, you can't just look at the behavior. You've got to really get an understanding of like what's happening when these sounds hit this animal's head, and what can a brain possibly do that might pull all this stuff apart.

SPEAKER_00 52:04

And so the sec, if I recall the second part of the argument, the one is this the way too much distortion, too noisy environment, too much masking, whatever. And the second part was that you know evolution would have optimized these sounds. Like it's crazy that they would have that they would either be echolocating. If if if a click works for most animals, why are they reinventing, you know, new sounds, new syllables every year? Um that makes no sense. So, you know, what would you say about that in the context of this of the idea that there's a lot to learn about these uh mammals' brains?

SPEAKER_05 52:34

Yeah, so it's again, I think this is sort of a historical problem that's arisen because the first echolocation that was identified in cetaceans were these click sounds. And the click sounds are ultrasonic, meaning above our hearing. Uh, they're very directional, and people like to think of them as almost like a flashlight that the dolphin points at things. That's an acoustic flashlight, and then they can use that to tell where where something's at and maybe what it is. And that's a very different scenario from what the what I'm suggesting the Bailey and whales are doing because their sounds are audible, number one, we can hear them. And when they go out in the ocean, they're not in a flashlight beam. It's more like if you're imagining like floodlights coming on at a prison when people escape, it's like lights going everywhere in all directions and it's illuminating everything. And that's a very different kind of processing that a click is not gonna work in the same way. So if you imagine, like, okay, oh, they're not trying to say, let me point this sound at a particular thing that's like two meters in front of me, but let me just expand my perceptual horizon for five kilometers in every direction at the same time. The kinds of sounds that are gonna be good for that are gonna be very different than clicks. And as a matter of fact, if you look at what the the U.S. Navy uses for sonar, they don't use clicks because they wouldn't work. They use sounds that are much more similar to what humpback whales use. They're sonic, you can hear them, they're extended, they're producing more slowly than what a dolphin does, is because they're looking for submarines that are very far away, they're much bigger than a fish. So you need a certain kind of sound to detect certain kinds of targets and certain distances, and clicks just aren't going to cut it. So even the humans' best uh surveillance techniques with sound are using sounds that are not click like underwater.

SPEAKER_00 54:12

We're we're talking about the difference between um clicks and the vocalizations of the whales, how they you know, how they may be interpreted, and it it um it led me to think about how when an acoustician is tuning a room, um, they'll use like sweep tones. They don't they they use clicks sometimes too for for reverberation, but they'll you know they'll do like broader frequency sweeps to see how the environment is reacting to different frequencies. And so I I don't really understand why we're probably on the same side on this, but I don't understand why uh an animal wouldn't want to do that. You know, it seems like an oversimplification to say like a click is all you would need, so anything else can't possibly be equolocation, right?

SPEAKER_05 54:53

Right. Well, so certainly bats don't use clicks, so it's it's for sure the case that animals will evolve sounds that aren't clicks to echolocate. As a matter of fact, if you use the the fact that there's many more species of bats than any cetacean, then most echlocators are not using clicks. I think the advantage of clicks underwater is that because the clicks are very precise in time, um you can get much more precise timing information back in terms of like distance from a target. So if you're trying to close in and maybe you can get a much more detailed read on what the animals are doing to try to escape in a very short time period. So maybe that maybe that's the advantage to clicks. Um probably it is. But yeah, for sure, there are definitely signals that would work better than clicks if you're trying to detect things that are far away

What About Other Baleen Whales?

SPEAKER_05 55:37

that are larger.

SPEAKER_00 55:38

And then what about the other baleen whales?

SPEAKER_05 55:41

Yeah, so humpback whales have been saved the most because I they're most accessible because they're near these coastal environments. But in the last, I would say 20 years, there's been more interest in other whales that are singing, including bowhead whales, blue whales. All the baleen whales sing, species of baleen whales sing except for a couple. And so, and now we have much better systems for recording like entire ocean basins with like bottom-mounted hydrophones and things like that. So bowhead whales now are known to produce songs that are quite complex compared to, say, like a blue whale or fin whale. So the blue whale and fin whales have the simplest songs, they're basically just repeating one or two sounds over and over again, although they do modify them sometimes. So I would say there's more data on recordings on the actual songs being produced by other baleing whales, but very little is known about their behavior while they're singing because these other animals tend to not be as accessible. They're in water that's not as clear and it's colder and they're moving, and so you can only see them a little bit. And so I would say that the all the other bathing whales are kind of like at the same stage humpback whales were 50 years ago. The very beginning, they're just now actually recording the songs and saying that's that well making the song without really being able to see what's happening in the context of them singing.

SPEAKER_00 56:55

What's the new uh information about bowhead whales that you're referring to? Their songs?

SPEAKER_05 57:02

Um, so they also seem to be do producing different songs um in different years, but they're not modifying them in the same way that Humpback Wells are. Their songs are shorter, um, you know, a few minutes as opposed to like 20 to 30 minutes for Humpback Wells. So a lot of the information is just that they are producing more complex songs than people thought they were.

SPEAKER_00 57:22

What about frequency range?

SPEAKER_05 57:24

It's pretty similar to the humpback well. So the humpback well frequency range is pretty astounding, actually. So they're making sounds that are infrasonic, rarely, but sometimes when they're singing, um, all the way up to like uh fundamental frequencies of five, six, seven kilohertz, which is way higher than a professional soprano human can produce, even though we're a lot smaller than humpback wells. So it's the fact that they can they basically can exceed the full range of all humans on the planet um on a daily basis without seeming and and extremely loudly too. It's just amazing that any animal evolved that wider range of sound production ability.

SPEAKER_00 58:02

Right. And of course, because we can hear most of it, you know, it it it appeals to us. You know, going going back to the bats, I was just thinking about how their songs are are probably would would probably be you know fascinating to many more people if they were you know slowed down into a range that uh you know accommodated our hearing.

SPEAKER_05 58:21

Yeah, yeah, if we could hear them like we hear birds, then people would probably be a lot more interested.

Bat Echolocation!

SPEAKER_00 58:25

Exactly. And and speaking of bats, there's one other thing that I want that we haven't talked about, but I think it's a really big part of the book, and so I wanted to ask you about it. It's it's this um the this flip-plopping. And and and if I'm understanding that correctly, it's it's the idea that they may be echolocating with sort of multiple streams, right? They're gathering, they're they're not, it's not just one click one moth or one click one um you know fish that an animal is trying to eat, but that they're you know they can send out multiple signals and process multiple signals, and that that that sort of further convinced you of echolocation.

SPEAKER_05 59:00

Yeah, I was actually kind of amazed when I discovered, I mean, I didn't discover it, I discovered other people discovered that the bats were using these kinds of alternating signals when they're echolocating. And I would say that they're actually not entirely sure, even the bat researchers, why the bats are doing this. I mean, that they're all I think pretty confident that it has an advantage, that bats are gaining some information that they wouldn't have gained if they just stuck with the one sound. Um, but it wasn't really uh recognized early on because it they usually only do it when they're um kind of flying, not capturing prey. So a lot of the research are focused on the sort of capturing part because that's the easiest to kind of like see what's happening, as opposed to a bat just flying in the air and doing nothing other than flying straight. That signal, the flip-flopping signal is a search signal, is what it's presumed to be um for. So searching for where prey might be or places where the prey might be. Um so longer range, maybe bigger targets, like groups as opposed to individuals. They've been documented. There's probably like 10 species at least now that have been documented doing something like that. And I think in for none of them have they actually confidently said what the advantages that they're doing. They're not all doing the same thing, but they definitely, if you hear them, if you like slow it down to the point you can't where you can hear them, you definitely can hear the pit them changing the pitches and doing it in a regular manner. So it's like boop, boop, boop, boop. Not like that, but they're alternating like that. Um, and so I think it's it's for me, it's I was I was kind of surprised that these bats were doing this and people didn't really know what what they were getting from it. And but I was even more surprised when I saw the the pitch changes in the timing because it was very similar to what I'd seen in Humpback Wells before it ever looked at bats, and I was like, oh, so maybe it's even closer than I'm thinking it is because they may be hitting similar constraints in terms of this how far can you do it, what what are some tricks to get around that? It seemed like a pretty big coincidence that it's both when you're the longest ranges where you have this kind of alternation thing happening.

What This Means for Studying Other Species

SPEAKER_00 1:00:58

Yeah. Cool. I I have one sort of more uh you know area that I want to cover before we do some listening of our own. And um I'm I'm interested in this idea that uh so much of the counter-arguments to um your beliefs are based on um you know human perception, and that well, you know, we hear this, and from what we hear or what we see on a spectrogram or whatever tells us that it it can only be this or can't be that. And I I thought it was very interesting to learn that humpback whales have something like um you know 2,400 cells in their auditory nerve per millimeter or something compared to humans having a thousand. Is that more or less correct? Yeah, yeah. And that the um that the eardrum of the uh humpback whale is shaped very differently than humans and it molts every year? Is that correct? So I wondered if you could just talk a little bit about you know those two features and how radically different they are from the way and and what they could mean for perception of another of another species.

SPEAKER_05 1:02:01

Yeah, so there's been uh all the uh knowledge about humpback well hearing is for the most part based on anatomical studies. There haven't been recordings from humpback well ears or anything like that to see what's happening. So it's all based on comparative work of what we know happens in other animals and who have similar anatomy, and so we're gonna use that to kind of judge what might happen in a well. In the case of the eardrum, it's interesting because it's not even clear if the eardrum is serving a function for hearing at this point. It may have adopted an entirely different function. And part of that's because the way that the sounds come to a well's ear is very different from what's happening in terrestrial mammals because, like in a human, the sounds will are coming through air and then they have to kind of be transmitted from air into like a mode that the brain can deal with. But it's it's also like bouncing off your head like it's an object, right? But in the case of the ocean, the sounds actually come through the well's body from all directions. They don't really need an outer ear, their whole body isn't is like a pinna or outer ear. And so the sounds can come in from anywhere. They don't necessarily need to trans be transformed from one medium to another because they're already in the right kind of tissue fluid medium that the ear was designed to deal with. And so already it's not clear that the eardrum would serve any purpose for them, but even if it did, the sounds are coming from everywhere. So what which sounds would I mean they're acting activated from all directions at the same time, almost unlike our little tube system we have. So yeah, I don't think anybody has a clue or is confident about what the eardrum's doing in the hearing context. When it comes to the nerves, though, it's pretty standard mammalian um structures that are the kind of entry point into the brain. And if you look at what's happening in not only humpback wells, but all cetaceans, they have way more neurons that are innervating like the sensory receptors of their ear than what a human has. And humans are really good at hearing among mammals. We're not like, I mean, we we're quite good at telling sounds apart compared to most other mammals and birds, and we're doing it with a lot less neurons. And so I think everybody believes, and there's pretty good reason to believe this, that when you're putting more neurons like in your retina or in any sensory system, it's probably so you can get more information from that sensory system. And so the fact that humpback whales just have so many um neurons monitoring what's happening to their ears already suggests they're doing something very different from what a human or bird is doing. Because otherwise, why have that many neurons kind of like focused in on this one sensory organ? But no one's really, I mean, so my interpretation is that they need it to be able to deal with all these variations in the subtle uh changes associated with echoes. Other people are um they they just say, like, oh, that guess they're very good at hearing for some reason that's unspecified.

Intro to Field Recordings

SPEAKER_00 1:04:49

Great. So at this point in the show, I typically like to listen to some mystery sounds, and um, and then you you know, I try to guess what they are, and I'm always so far I'm um I'm oh for however many we've done. Um, but in this case, I'm guessing we're gonna hear whales, so there's a little bit less mystery. So I'm just gonna let you go ahead and um you know play a few things and and we'll we'll talk about what

Short Whale Song Clip

SPEAKER_00 1:05:14

they are.

SPEAKER_05 1:05:14

Okay. So the first thing I'll play is an individual whale singing. You have to imagine this well, maybe is it this whale was recorded in the day, but imagine that the whale's hanging underwater at night, no other whales are around, it's not moving, and it's making um this sound maybe for like 15 hours non-stop, even when it comes to breathe, it's not stopping. And so you'll be hearing sort of a sequence of sounds, silence, sound, silence, and this is this kind of like almost like mantra-ish is like typical of what you would hear if you were very close to a well that's underwater.

SPEAKER_00 1:06:53

I had I have several thoughts. The first is that I do think it's it's strange and beautiful. I also think it sounds a little bit like um, you know, when a kid comes home after the first day of band class and he's been like assigned the trombone and he doesn't know how to play it yet, and he's just blah blah blah doing whatever making whatever sounds he can. And I also think about how I think it's in somewhere in the beginning of the book you mentioned that the first time you heard sounds like this, you thought it sounded like a like a cow would eating some bad grass or something. You didn't you weren't as enchanted as Robert Queen. But so that sound um for 15 hours that whale the whale would be making more or less that that those sounds.

SPEAKER_05 1:07:37

Yes. Except for they changed their sounds over time. So you heard like a minute and 40 seconds, and a typical full song would last like 15 minutes. You probably did hear that the whale was varying the sounds even in that short segment. It'll keep on doing that. And so you'll hear a variety of sounds uh over the 15 minutes that you didn't hear in this recording. Um, but they'll be the same kind of pacing. Some of them will be shorter, some of them will be higher pitched, some will be lower pitched. And I'll play a song in a minute, you'll get to see some of the variety of sounds they do. But that kind of like consistent, almost like swing slow-motion swing study production will keep on happening. Um, you can and often you can't even tell when they're at the surface because they just keep on going and they breathe between the sounds.

SPEAKER_00 1:08:16

So it it seems to me that in terms of like energy, it would be very costly to do this. And if you were trying to um you know win the interests of a of a female, it seems like you'd either give up or move around or something. And if you're trying to echolocate, like why do you need so much information about exactly where you are if you're not moving? So right.

SPEAKER_05 1:08:41

So for the first point, uh the way an analogy I like to think about is like imagine that you want to get a date, and your strategy is to go buy uh a set of roses and stand out on the sidewalk and just hold it up, and then maybe and it's just a random sidewalk, not in New York City, but you know, off in the some country somewhere, it's like that's probably not the best strategy for like getting a mate. Maybe you should find the mate first and then present the flowers or something like that. Don't just sit there for 20 hours with the flowers. So it seems weird to me from that perspective of like that's a lot of singing for nothing, you don't even know if there's another another well around you. Um, why would you spend all that time? Now, from your perspective, uh from the son art is like, well, you don't know where the female is at, and you're literally scanning the environment to see if any show up. So it's more like fishing. So you can imagine your fishing may throw out the line a bunch of times and never get anything, but then when it starts you start seeing like some evidence, like, oh, now something's happening. So there the idea is that they're searching continuously, and you have an advantage of searching continuously if you've sort of been scanning the same environment because they're not moving, right?

SPEAKER_02 1:09:47

Right.

SPEAKER_05 1:09:47

So you've got you know what the normal looks like. And so when something, I mean, when you detect a well, it's gonna be very tiny, like it's weird to think of wells as tiny, but it's like when they're five miles away, they're tiny.

SPEAKER_02 1:09:58

That's right.

SPEAKER_05 1:09:58

Um, and so it's like you're detecting a gnat and it's like kind of almost almost like a plane flying overhead at night, and you're seeing a light moving, you're like, oh, I know these stars, they're all stationary, but now this one's moving across them. And that's how you detect it. So in that context, just sitting there for a long time is you're actually getting a benefit from it because you've really established what's the nothing that's the ground that you're trying to take these figures from. And then when they show up, you'd be like, oh, here they come, there's one there. Um so I feel like in that context, you have to be constantly vigilant, and you and that's what the why you would do it for 10 hours, because you don't know when the whale's gonna show up.

SPEAKER_00 1:10:34

Right. In the book, you talk about how um, and I could be getting this word wrong, uh, but it that that um humpback whales are um arteriodactyls.

SPEAKER_05 1:10:42

Is that um they're in that group, right?

SPEAKER_00 1:10:44

Yeah, and and which also includes um rams and you know other you know, cows, pigs, camels. Um but you you you mentioned how uh uh uh rams as a part of mating will look for the a position where they have the best view.

SPEAKER_05 1:10:57

Right, they'll go to a very high high spot so they can see them very far away.

SPEAKER_00 1:11:00

Yeah, so kind of similarly staying in one position, but uh but continuing to vocalize, you're maintaining that expansive view until you find what you're looking for.

SPEAKER_05 1:11:08

Right. It's a it's an efficient search strategy if you're at a high vantage point and you can monitor a wide space simultaneously, it's much more efficient than kind of just walking around in the forest and trying to hook you run some some.

SPEAKER_00 1:11:18

So potentially this animal's found this particular humpback has found like a good view, but needs to keep looking with sound.

SPEAKER_05 1:11:24

Right, because they don't know like uh maybe another well doesn't show up the whole day. Right. But maybe one when that you know that one female that might be interested in like meeting him.

SPEAKER_00 1:11:32

Yeah.

SPEAKER_05 1:11:34

You want to make sure you detect that one.

SPEAKER_00 1:11:35

Yeah, cool. What uh what's next?

Slowed Bat Echolocation

SPEAKER_05 1:11:37

I think maybe I'll give you some, you mentioned flip-plopping bats, so I'll give you some examples of that. So this is a unaltered bat s sonar signal or the bat searching, okay, um, but slowed down by like a factor of 10. So you'll be able to hear it, whereas in nor normally you wouldn't be able to hear the beat. So it's basically been stretched out in time. So this will be coming occurring much faster for the bat and at much higher frequencies. Um but this is the the the structure is gonna be maintained.

SPEAKER_00 1:12:44

It's interesting they changed the duration. Um can we hear the echoes? I feel like we can. So those those are the those are the echoes of that um sound producing animal, not another bat farther away or something. Interesting. Yeah, um it it it's haunting and beautiful. I could listen to that for for for a long time. But I think it's interesting. I mean if you would have asked me, you know, I've been I've been aware of um bat echolocation, you know, since before I became more interested in bioacoustics generally. And if you would ask me a long time ago what is bad echolocation, I think I would have said, oh, they click. You know, but but those are definitely not clicks. Right. You know, there's there's so much um uh pitch envelope, you know, and contour to it. It's it's uh it's it's really fascinating.

SPEAKER_05 1:13:29

They, I mean, so I'm giving you a very it's kind of a similar situation was with the um whales. I'm giving you a very short sample, but they do modulate those things. They're not just kind of locked into like one set of pairs that they produce, they can go up and down for both of them or one of them. Um and they can switch to shorter sounds um and they can modify the modulation as well.

SPEAKER_00 1:13:48

Cool. What do we uh what do we all?

SPEAKER_05 1:13:50

So you've heard sort of a haunting uh bat echolocation, which no one probably would think it would be haunting if we were talking

Full Humpback Whale Song in 3min!

SPEAKER_05 1:13:58

about it. I'm gonna now play an entire Humpback Wells song, which is the shortest Humpback Well song I've seen. Umsu, if you look in the literature, they say the shortest is like five minutes, but this one's less than three minutes long. Um it's quite distant, so you'll be able to hear echoes from it as well, kind of like in this one you just heard. It's gonna be quite distant sounding, but it has every component of the wells song from that year, every sound that the wells produced that year, but it's kind of like a um the micro version of it. Because they're not doing it as much as they normally would, they kind of just rapidly go through all the entire sequence. So I think it's good for you can hear the full range of sounds they're making. It's gonna start off with higher some higher pitched sounds, which may not sound like a well, but they are. And then at the end it'll have more rumbly sounds, which you almost can't even hear, but you maybe can kind of get a hint of them happening. So this is unaltered, other than I filtered out the highest and the lowest frequencies to make it more audible. But it's this is the the natural rhythm, the natural pitches that are being produced.

SPEAKER_00 1:17:23

It sounds conversational. You know, it I mean, even though it's one one animal, it sounds like it's a a conversation with itself. It's very call and response. But yeah, yeah, it's it's equally easy for me to imagine each one of those signals um, you know, having a sort of different surveying function that's that's ordered. And you know, I got this piece of information, pause, which I think is another thing that you mentioned in the book that we didn't really talk about. There's so much information in the space between the signals, right? That's what that's what this um is is maybe overlooked sometimes in the you know the sort of mating strategy um you know uh position. Um but you can really hear it there. You know, when you listen, you you can you know you can hear some the the echoes and and and the decay of each one of those articulations, and it's it's it's beautiful, but it's you know likely also informative in other ways.

SPEAKER_05 1:18:14

So there are definitely parts of the song, especially when they're in these sort of reverberant environments where you hear them and it sounds like you can imagine some uh like a person singing like an aria or something in little bursts or something. Um and then there's other parts that sound like grunts or like indigestion or whatever, and you're like, that does not seem like people would be singing that. Um so that you definitely can kind of relate to parts of it, and other parts are like, oh, that's odd. But yeah, it's just a wide range of things that these wells are doing. Um and we humans focus on the parts that sound most familiar to us, right? And the sort of silent parts and the reverb, we're kind of like, oh, I guess it's like there, but whatever.

SPEAKER_02 1:18:50

Right.

SPEAKER_05 1:18:50

All right,

Killer Whale Song Clip

SPEAKER_05 1:18:51

so I think the the last one I was gonna play is much shorter. Um but this one I think is interesting. Uh the original title for the book was gonna be Why Wells Sing and Dolphins Don't. And it got reduced by the editors, but that's fine, it's good. Just in the same sense that uh researchers think that only that no baleen whales equate. They also claim that no uh toothed whales sing. That's only the baleen whales that do it. And I think that's also a mistake, and that they're kind of assuming that whatever the uh the dolphins do by definition is not singing because it doesn't sound like a humpback whale or a blue whale, and it's like, of course it wouldn't sound that they're totally, you know, they're much smaller, they're very different in the situation. So I think that they probably are singing in the sense that if you think of singing as being repeating sounds and patterns that have structure that are rhythms and melodies, so to speak. Um and so I was there's a paper that came out recently where they described and provided samples of killer wells producing pattern sound sequences. They don't call that singing, they call it call patterns because they it can't be singing because it's a talk well. But I it'll be interesting to hear one of these. This is a pattern produced by a uh killer well, but I'm gonna play it at half the speed. I can play it. Actually, I'll play at the natural speed first, and then I'll play it at half speed. So you can see the kind of rhythmic structure that this whale is producing. And the wells would typically I'm gonna play one, but they typically would repeat these patterns. That's why they're considered to be patterns. So that's what they normally would sound like. Yeah, that's full speed. And then I'm gonna play it like a half speed. So those would be considered to be not equallycation calls, I mean though there are clicks in there, and not singing, but some kind of intermediate communicative calling. And but they don't really know why they're making these patterns and they don't know what the importance is for a killer well. So my argument would be like until you have some data or experiments, maybe be neutral and say, like, these sounds have a lot of gaps between them. Maybe that have you ever looked to see how this sound would bounce up another orca? Maybe they're not just talking to each other, they're also using this sound to tell like where all the other orcas are around them that they can't see. Um, and it would be this essentially the same function as the Humpback Well song in that context of like I'm gonna hear where other animals are at, as opposed to just like magically know it.

SPEAKER_00 1:21:36

I'll be looking forward to the the next volume, then why orcas don't or why why why orcas sing.

SPEAKER_05 1:21:42

Yeah.

Closing Statement and Ending Theme

SPEAKER_00 1:21:43

Um, thank you so much for being here. This is this has been fantastic, and um, I want to encourage everyone who's uh watching to buy and read this book. It's fantastic. Eduardo, thank you so much for making the time and for being here. And um, I learned a lot and it was a lot of fun.

SPEAKER_05 1:21:58

Oh, thank you for having me.

SPEAKER_00 1:21:59

Thanks.