Scientists say we got whale song wrong

When Eduardo Mercado first heard humpback whales sing, he was mesmerized by their rhythmic, moaning, frightening sounds.

Mercado is a bioacoustician – a scientist who studies the sounds made by animals, and he was not C.He came to believe that humpbacks’ songs were mating calls, as many scientists believed at the time.

Instead, he wondered whether they might be using their songs as sonar, the way dolphins such as toothed whales are known to do. This led him to a lifelong pursuit of trying to figure out what his singing really meant.

Mercado, a professor in the psychology department at the University at Buffalo, has put together his decades of research in a new book called why do whales singThis is part of a conversation with him quirks and quarks Host Bob McDonald.

What exactly is whale song?

Whale songs are not exactly like human songs or bird songs, because they have no beginning and end. If you record very large whales – baleen whales, including humpback whales – if you record them while they sing, in many cases, they will keep making sounds continuously for several hours. And if you monitor what they’re doing, you’ll realize that they’re cycling through a certain sequence of patterns. But it has no clear beginning or end. It’s like an acoustic carousel, where they always spin in the same order.

You argue in your book that whales don’t actually sing in the way we humans think of the term. What do you mean by this?

Historically, since the 1970s, researchers believed that what whales were doing was essentially the same as what birds do when singing, presenting a display that other animals could hear and assess the quality of the singer.

What What I’m proposing in this book is what I’ve been proposing for some time, What scientists are calling songs is actually a sophisticated form of echolocation, similar to that of bats, but on a much broader spatial scale. So the whales are not performing for other whales, but are actually exploring, generating their own internal view of what is going on around them.

Why do other scientists think that songs are actually courtship rituals?

There are several reasons why people are convinced that this is what is happening. I would say the number one reason is that the majority of humpback whales that had sex while singing were males, so it’s a sex difference. They are often singing in contexts where reproduction is taking place, so it definitely has something to do with sexual reproduction. And then its complexity itself makes them think it must have some kind of display, like a peacock’s tail.

Why didn’t you like that idea?

I was analyzing the sounds within the songs. And I noticed after about a decade of analyzing songs that were recorded before I started, that the sounds they were using were changing over time, from year to year, in such a way that if you made an alphabet of the sounds they used in 1992, that alphabet would no longer apply in 2000.

And it seemed strange to me because no other mammals were doing it, and birds certainly weren’t doing it. It is like the peacock’s tail which keeps changing every year. And I don’t understand how it would be judged by other whales if there wasn’t always something stable about it that would allow you to say this is the best kind of song you can make.

So what made you believe it might be sonar?

I was studying dolphin echolocation at the time. And I’ve read some studies about belugas, which, when they echolocate, generally do normal dolphin echolocation by producing clicks and getting the echolocation back. But if you ask them to echolocate things that are really far away from them, they go into a different mode of echolocation, these little bursts of clicks. I was like, oh, so if you’re going to echo things that are too far out, you need to do something different than the norm.

When whales are singing, they are alone, and almost always they do not move.– Eduardo Mercado

And then I started looking for additional evidence of animals that are echolocating very far back, like bats, and I discovered that they were doing the same thing as whales and doing it in very similar contexts, and then trying to see what the implications of that would be. And, I did some experiments looking at the physics of it, to see whether it would be possible for a whale to detect another whale two kilometers away using its song, and it worked physically.

How have you come to study the sonar capabilities of whales throughout your career?

So I’m attacking it in a number of ways. The first was analyzing the sounds themselves to see what the amplitude of the sound is, and the environment within which they are making the sound, the physics of how far the sound can actually produce echoes that would be useful.

My main research really focuses on how learning changes the brain’s sound processing. This occurs in almost all mammals that have been studied and certainly in humans. And so most of my research over the last 20 years has been just looking at how quickly the brain can change the way it responds to sounds, how easily it can pick up very small differences through repeated experiences.

How far can a whale’s sound travel underwater?

If you’re talking about humpback whales, in most contexts where they sing, their sounds can easily travel up to 10 kilometers. These can be identified even up to 100 kilometers away. And if you’re talking about other whales like the blue whale or the fin whale, their songs have been detected up to 1,000 kilometers away, which is pretty impressive for an animal.

What happens with echolocation is that when it hits an object, only part of the sound is reflected back. So if you produce a very loud sound, you are only getting a small portion of that energy back. The intensity of the sound is not meant to actually carry it far, but to make echoes that are not that far away recognizable.

So what are whales actually seeing with their sounds?

Based on my analysis of what the sounds are like, they are primarily focused on larger targets that will be moving. I think they really care about what other whales are doing. Unlike dolphins, they do not spend their lives with specific individuals, they are all nomads. They are all on their own. And they are not always in the same place. They are migrating from Antarctica or Alaska to some tropical island and back every year. And they may never see the same whale twice in their lifetime.

When whales are singing, they are alone, and almost always they do not move. So they’re just hanging there in the water. But then when they actually swim, they stop singing and usually swim in a very directed manner. So it’s clear that when they start swimming, they have decided, singing time is over and I have to be in some position based on what they have learned.

So I think it’s a matter of them keeping an eye on what’s going on around me. It’s a kind of exploratory social scenario where they can actually monitor what other animals are doing that are located 10 kilometers away, scan really wide sections of the ocean and keep monitoring when new whales appear and when they leave.