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The Tufts Daily
Where you read it first | Sunday, May 19, 2024

Three dimensions of humpback whale communication

Dr. Michelle Fournet dives into the nuances of humpback whale language, shedding light on how increasingly loud oceans are leaving marine mammals acoustically overwhelmed and disoriented.

Marine traffic

Vessel traffic is a large cause of disruptive marine noise.

Editor’s note: This interview has been edited for length and clarity. 

Amelia Macapia (AM): Whale songs can travel vast distances, and if they are using their songs to communicate with one another, they are not just doing so across space, but also across time. That concept flashed briefly in your documentary “Fathom.” I came across a recent quote in an article by Elizabeth Kolbert in The New Yorker, suggesting that a call “made by a humpback whale near Bermuda would take 20 min to reach a humpback whale swimming off the coast of Nova Scotia, and if the Canadian whale answered immediately, it would be 40 min before the Bermuda whale heard back.” So, are the whales receiving information from the past and present simultaneously? And how are they registering that?

Michelle Fournet (MF): The only way that we can begin to answer that question is creatively. What we can do is think about what it means to live in a three-dimensional medium and what would happen if we scaled our life up. I’m 5 feet, 5 inches; I can yell across a football field and somebody can yell back to me. If I think about what it’s like to have that interaction and then couple it with everything I know about the ecology of a whale, I might be able to start to imagine what it is like to be able to integrate information from the past and the present simultaneously. For humanity, this is not the only time we have dealt with problems of scale. There is a star that is about to get brighter. It is a red giant star feeding into another star that every 79 years or so becomes really bright. It lights up next to the North Star. And yet, we are capable of integrating this concept that during the Bronze Age there was a fire in the sky an inexplicably far distance away, and we can put that into our own historical context and attach meaning to it.

We are small and comparatively puny when you put us next to a whale, so for a whale to have to integrate time over 20 or 40 minutes, I imagine that it does so effortlessly. Everything for them occurs at a scale that is slower, bigger, wider — and to anthropomorphize them — maybe that just means that they are more thoughtful. Or maybe it just means that they are capable of integrating across more speeds than humans are capable of. But for now, all we can do is take what we know about science and use our imaginations to think about what it must be like to communicate across that sort of space and time.

AM: I have this image in my mind of you in the field, like Jodie Foster in “Contact,” sitting with your headphones on — it’s great. Your background is mostly in non-song vocalizations, or calls. What sorts of calls are humpback whales making and what communicative patterns are there?

MF: When I first started studying humpback whales in 2007, we did not have a good handle on what sounds humpback whales made other than song. I started listening to calls in part because I was living in Alaska where the whales were not singing as much, but also because only male whales sing. What about females? Should we be paying some attention to what the other half of the population is talking about? Song is a culturally transmitted sound, and it changes quite rapidly. But imagine how much we would miss about human culture if we only studied music, and we never studied literature. 

I’m interested in globally consistent traits shared by whales. A call that has most captured my interest is the whup call. This sound is produced by male whales, female whales, baby whales and old whales. It’s in every population we have ever looked for, and it’s been conserved over generational time, so there is strong evidence that it must be important. Going back to this question of scale, the whup call occurs at close range between whales, which means that I can observe it myself. We think that it is a contact call, so it is a way for whales to announce that they have entered an acoustic arena and to say, basically, “I am here.” Then, another whale can respond and say, “Oh, I am also here.” But the work that I’m doing currently is looking at individual variation in this call. So it’s not just to say “I am here,” but another whale might interpret, “You are here, and this is who you are.” For whales in Alaska, they maintain relationships that last for decades; they can break apart from and rejoin the group. How do animals maintain relationships if they are constantly being separated by vast oceans? I think, in part, they are recognizing one another by the sounds of their voices and this sense of voice is encoded in that contact call. 

AM: As we are trying to understand what whales are saying to each other rather than trying to talk to them, can you explain more about what the acoustic ecology is like in their environment?

MF: My favorite analogy when we think about the acoustic ecology of whales is that human language is like a rainbow. It is easy to tell what is red and blue and green, but you know the edges between red and yellow get a little fuzzy, and you get orange. There is a gradient, but it is mostly discrete. Whereas humpback whale language, if you want to call it language, is like a sunset. You never can quite tell where one sound starts and another sound ends. But you can definitely tell the difference between yellow and purple, and you can tell the difference between red and green. There is an almost infinite gradient between one sound and another sound, and one bleeds into another. When you think about how whales are communicating with one another, it is hierarchical. There are things that are very clear that are different. But there are also things that are continuous. It is a bit like reading an analog clock. We have to imagine that the information whales are getting from one another is quite subtle. And I think that is really beautiful, that the information they are getting encodes things about how big they are, how hungry they are and whether or not they are in a state of aggression or arousal. The acoustic ecology of humpback whales is quite nuanced, but the flip side of that is that they are perfectly capable of producing stereotyped sounds, and we see that in song. There is something about their acoustic ecology that benefits from having this system of stereotyped, repeated, structured advertisement coupled with this much more fluid, continuous, gradient and disorganized calling structure. I think that that speaks to the intelligence of the animal: that they could have a two-fold system of communication and that they can so effectively interpret both sets.

AM: If we transition more to talking about human-produced noise, you have spoken about how we are pushing our sensory world onto the animal world, especially in terms of industrial shipping and vessel traffic, and the spillover effects that's having on animal populations. I recently came across your work with bearded seals, and that there is a threshold for how loudly they can communicate with one another and that they will not be able to get any louder. Are we totally destroying their communication ecology? Is that something that they are able to adapt to?

MF: Are we totally destroying their ability to communicate? No. Are we significantly limiting their ability to communicate in the way that they have for the past 150 million years? Yes. Before humans put vessels in the ocean, the ocean was still noisy. It rains, it’s windy and there are volcanoes underwater. Underwater animals evolve acoustic abilities to contend with natural sound sources. Humpback whales are really loud. Snapping shrimp are also really loud. If a humpback whale wants to be heard above the din of snapping shrimp it has to call louder. So, they have some evolutionary predisposition to contend with noise. Since the industrial revolution, the amount and rapid change in ocean sounds is far faster than any large, slow, reproducing animal could keep up with on an evolutionary time scale. 

Whales cannot evolve fast enough to adjust their calling behavior to contend with anthropogenic noise. For some animals like underwater breeding seals, it is an important strategy to call as loud as they can. The louder they call, the bigger their territory, and the more likely they are to attract mates. They do not have room to call louder. We are close to reaching unsustainable and destructive levels of noise in certain parts of the ocean that have critical implications.

The thing about noise that is different from other forms of pollution is that we have the ability to turn it off. We cannot go through and magically remove all the plastic from the ocean. When we have oil spills, most of the oil is going to sink and cannot be retrieved. But when you turn a boat off, the noise stops. If there is an area where there is hope for humans to change their behavior in a way to give the ocean some breathing room, it is with noise. As it currently stands, ships are entering places in the Arctic where they cannot yet responsibly be due to the excessive noise they are producing. We are never going to take humans away from the equation. Humans will be in every ecosystem from now until the extinction of our species. It is an irrational and irresponsible dream to say that we can eliminate the human element. But we are good problem solvers. We have to figure out how to responsibly engage with the ocean soundscapes we have. 

AM: As we are thinking about reaching these unsustainable levels of noise, how are you trying to get that message across to people?

MF: My job is to generate knowledge, but also to disseminate knowledge; a big part of that is through teaching. With media, people get exposed to topics that are interesting, and they engage with them in a short period of time. But, when you teach a class, you don’t just teach someone about something — you teach them how to think. We have a whole section of the class that I teach about the Industrial Revolution and about the interrelatedness of whales and humans. We start in prehistoric times and move all the way to the modern consumption of whales via social media. My students might not become whale researchers, but they are becoming critical thinkers and critical consumers of knowledge. We cannot be the gatekeepers of knowledge. We must understand the science, we must tell the stories and we must tell them in a way that people can understand them. If I can do that, maybe I can change the sway of public opinion. To be a good scientist requires creativity in so many ways: from how we design studies, interpret the natural world, consume evolutionary knowledge, to how we tell the stories of our work.

AM: How do you think we can more responsibly engage in ocean soundscapes? Are parts of these solutions about passing regulations about how fast vessels can go or establishing more marine protected areas?

MF: Marine-protected areas only help if you have vessel restrictions within your marine protected areas, but a lot of them do not. Responsible vessel traffic in critical areas, slowing down caravanning ships and speed limits are big ways of reducing the amount of noise. Changing human behavior is hard. But people love to see technological progress. I don’t usually throw my hat into the ring for saying, “We can engineer our way out of this problem,” but realistically a lot is going to be engineering quieter ships. I think that in the next 50 years, we are going to start seeing ships that are capable of potentially running on solar power or running on fuel cells or propelling themselves using quieter sources of energy that are also more sustainable. I’m hopeful that we will see engineers making quieter ships.