Scientist says we’ve got whale song all wrong
CBC
When Eduardo Mercado first heard a humpback whale sing, he was fascinated by their rhythmic, moaning, haunting sounds.
Mercado is a bioacoustician — a scientist who studies the sounds that animals make, and he wasn't convinced that the humpbacks' songs were mating calls, as many scientists believed at the time.
Instead, he wondered if they might be using their songs as sonar, echolocating the way toothed whales like dolphins are known to do. This set him down a lifelong path to try and figure out just what all their singing actually means.
Mercado, a professor at the University of Buffalo's department of psychology, has put his decades of research into a new book called Why Whales Sing. This is part of his conversation with Quirks & Quarks host Bob McDonald.
What exactly constitutes a whale song?
Whale songs are not quite like human songs or bird songs, in that they don't have a start and stop. If you record the very large whales — the baleen whales, which include the humpback whale — if you record them when they're singing, they'll keep on making sounds continuously for multiple hours, in many cases. And if you monitor what they're doing, you'll realize that they're cycling through a fixed sequence of patterns. But there's not a clear beginning or end. It's more like an acoustic carousel, where they're always going around in the same order.
You argue in your book that whales don't actually sing the way we humans think of the term. What do you mean by that?
Historically, since the 1970s, researchers believed that what whales are doing is essentially the same thing as what birds do when they sing, which is produce a performance that other animals can listen to and judge the quality of the singer.
What I'm proposing in this book, which is what I've been proposing for a while, is that what scientists have been calling songs are actually a sophisticated form of echolocation, similar to what bats do, but over a much broader spatial scale. So the whales aren't performing for other whales, but are actually exploring, to generate their own internal view of what's happening around them.
Why do other scientists think the songs are actually courtship rituals?
There's multiple reasons why people are convinced that that's what's happening. I would say the number one reason is that most humpback whales that have been sexed while singing were males, so there's this sexual difference. They're often singing in contexts where breeding is happening, so it definitely has something to do with sexual reproduction. And then just the complexity of it, makes them think that it has to be some kind of display, like a peacock's tail.
Why didn't that idea resonate with you?
I was analyzing the sounds within songs. And I noticed after analyzing songs from about a decade that had been recorded before I'd ever started, that the sounds they were using were changing over time, from year to year, in a way that if you if you've made an alphabet of the sounds they used in say, 1992, that alphabet would no longer apply in 2000.
And that seemed weird to me because no other mammals were doing that, and birds definitely were not doing it. It's like a peacock's tail that changes every year. And I didn't understand how this would be judgable by other whales if there wasn't always something constant about it that would allow you to say, this is the best kind of song you could produce.
