Short Wave - Lemurs Will Rock You

Episode Date: April 11, 2022

There's a lot for scientists to learn about the origins of humans' musical abilities. In the last few years, though, they've discovered homo sapiens have some company in our ability to make musical rhythm. Producer Berly McCoy brings the story of singing lemurs to host Aaron Scott. She explains how their harmonies could help answer questions about the beginnings of our own musical abilities, and what all of this has to do with Queen. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

Hey there, nerds. Before today's episode, we have a favor to ask. Do you have a favorite science joke? We need a few for an upcoming episode, and who better to ask than the world's best nerdy audience? If you've got something, record your name, location, and your joke is a voice memo in a quiet location, and then send it to us via email at shortwave at mpr.org. Thank you so much and enjoy the show. You're listening to Shortwave from NPR. Hello there, shortwavers. Aaron Scott here with producer Burley McCoy. Hello, Burley.

Oh, no, what is that? Those are lemurs. Hi, Aaron. Okay, lemurs, I'm getting a sense of what story you are bringing us today. What are we talking about? Exactly. It's everyone's favorite, singing lemurs. Everyone's favorite, you say.

Burley, what was the sample size on this pole? Okay, maybe it was a little small, but I promise, Erin, this one's going to be fun. I trust you wholeheartedly. So tell us a little bit about what's so interesting about singing lemurs. So much, so much. But let's listen to him again first. I'm all yours. Oh, it's so beautiful and haunting.

And also a little bit like whale sounds meets air horns. Right. It was definitely not what I expected. These recordings are from scientists who collected the songs from lemurs in Madagascar over the course of 12 years. And when the scientists listened closely to the recordings, they found something that's only ever been found in birds and humans, a kind of musical rhythm. Okay. Now it makes sense why you sent me that video of a dancing bird from 10 years ago. Yeah, Snowball.

That was a cockatoo that was filmed dancing, very good. clearly to the beat to a backstreet boy's song. Of course, classic. Yes. And after scientists saw it, they sent Snowball's owner some versions of the song that had been sped up or slowed down. And Snowball still followed along to the beat. So they knew he hadn't just memorized a routine.

He was actually keeping time with the rhythm. And I'm guessing that was a big deal because before that, scientists thought that only we humans had rhythm. Exactly. Now we know other species have musical rhythm. And by studying it, scientists hope. they can better understand the origins of music. So today on the show, what we can learn from the songs of an endangered lemur,

how it may give us insight into our own musical histories of species, and what all this has to do with the band, Queen. We are going to rock you, nerds. I'm Aaron Scott. And I'm Burley McCoy. And you are listening to Shortwave, the Daily Science Rhythmcast from MPR. Okay, Burley, so today we are going to talk about lemur songs. Something that scientists have only recently discovered his rhythm, right?

Yeah, the work was published in 2021, and it was kind of a big deal because it was the first time scientists had observed this kind of rhythm in a mammal other than humans. I'm looking forward to this, Burley. But before we start to jam out, lemur style, we need a little bit of a musical interlude. So you use this term musical rhythm, but that seems a little bit redundant to me. Like, isn't all rhythm musical? I thought the same thing, Aaron, until I talked to Annie Ruth Patel, who goes by Annie. He's a psychologist at Tufts University, and he studies music cognition. I think more broadly, rhythm is sort of structure in time, and sometimes rhythms can have a beat, but not always.

Structure in time. Yeah, that sounds a little bit broad, so what does it mean? Yeah, it was a little hard for me to wrap my head around as well. It means that there's a particular way that the sounds are organized, that it's not random, even though there doesn't necessarily have to be a regular pattern for a sound to be rhythmic. Burley, I think this is the point in the show where we get to encounter an example of a rhythm without pattern, right? Yeah, yeah, you are a great guesser, Aaron. I asked Annie that too, and he told me speech has rhythm. People talk about the rhythm of English being different from the rhythm of French. and when somebody speaks with a foreign accent and we are aware that they're not a native speaker,

part of what we seem to be queuing in on is the fact that their speech rhythm is not like that of a native speaker. But that's nothing to do with beat or regular repeating units in time. It's the way accents are distributed in words. It's the kind of patterns of long and short in syllables and vowels. It's all about proportions and how they relate to each other over time as things unfold. Right, right. Or where the pauses are. as important as the sounds.

Yeah, exactly. And here's another example of maybe a surprising rhythm. Think of Morse code, a highly structured rhythm, which has no beat. You don't tap your feet and dance to Morse code. Huh. I don't know that I would have thought a Morse code is rhythmic, but it is very structured.

So rhythm is something that follows a set of rules. So how did this group of scientists in Madagascar find out lemurs have rhythm in their songs? So I talked to Kiara de Gregorio. She's a postdoctoral researcher at the University of Turin in Italy. She analyzed the songs of this particular species of lemur. They're called Indri, which she had to collect by following them around the forest with a recorder. They cannot survive in captivity.

So the only place in which you can see them, it's their forest. And also hearing their song in the forest is very, I think it's how. I don't know, it's something that resonate in all the valleys and propagates in all the forests. And it seems that like all the forest is singing. It's a very incredible experience. It sounds magical. Yeah, and tiring. Kiara told me they would spend eight to nine hours a day for months following the injuries.

Oh, yes. I've tagged along for those crawling through brambles and sliding up and down muddy ravine sorts of field days. It's not pretty. It sounds exhausting. But by the end of it, they had all these recordings, and when they analyzed them with audio software, they found a distinct pattern. And this is that musical rhythm that you were talking about earlier.

Yeah, it's called categorical rhythm, which both Annie and Kiara explained to me has to do with the timing between notes. So like if the notes are equally distributed or not? Right. So Kiara measured the timing between the lemur's notes or the intervals, and then calculated the ratios of those intervals. She wanted to see if there was a consistent pattern of timing in the song. Intervals, ratios.

Burley, are you sneaking in a math episode on me? I promise, Erin, dear listener, we are only glancing at the math rabbit hole today. So, categorical rhythm. What is it? I want you to imagine a metronome. Okay, I can hear it. If you were to look at, say, three notes of a recording of that rhythm on a computer screen, and you measured the time between the start of the first note to the start of the second note, and compare that amount of time to the start of the second note and the start of the third note.

Those two intervals would be exactly the same. Exactly. And Kiara says this means this example of categorical rhythm has a one-to-one ratio. Okay, so a metronome rhythm or a one-to-one ratio is just one-one. example of categorical rhythm. Yep, it's considered one category. And so you can have all of these different ratios of spacing. So 1 to 2, 2 to 1, technically 18 to 1 could be possible.

And when Kiara looked at the injury song, she saw that a lot of the time their notes followed this 1-to-1 ratio, this metronomic rhythm, and a good amount of the time they also sang using a 1-2 ratio, which is even more complicated. Okay. What does a one to two ratio sound like? I'm glad you asked. This is our chance to finally talk about Queen, the famous rock band. Although Queen has to be slowed way down,

but our trustee engineer Josh Newell did that for us. If we think about the intro of the song, we will rock you, you know, the famous part in which we have the tum-tum-cha, we have a repetition of three, let's say, sound and Indri songs are more or less the same. We have, for example, three notes

and then an interval and then three notes. And in the We Will Rock You song, the three sound have the same interval between them. But between the two groups of sound in the middle, there is an

interval that is double. And it is the same thing happened with the injury song. I totally hear it. So I've got to say this isn't the most complex rhythm and rock history, but I'm guessing it's actually a complex process and pretty rare. Yeah, within our species, it's been documented in the music of almost all cultures that we know of,

but scientists had only discovered it outside of humans in some birds. Until these lemurs. Wow. And so do they think it's unique or that we could maybe find it in other animals? Yeah, I asked Annie that too. I mean, a lot of species have yet to be studied using these methods. So I wouldn't say that, you know, that it's absent in a lot of other species. It's just that we've only looked really carefully in humans and those birds that were studied and now these lemurs. But it raises interesting questions about what other species might have this property in their acoustic communication patterns.

It also raises the question for me, Burley, of whether looking for categorical rhythm in other species could help us to understand anything about the origins of music in our own species. Yeah, this brings up a really interesting debate among scientists who study how we evolved the ability to make and perceive music. Some think it's a byproduct of speech, but others think it's its own thing. When I asked Annie about it, he pointed out that these lemurs don't seem to have anything. that resembles human speech or language. I think this could at least show that one could develop fairly complex song-like behavior without having to come from some already established

complex language-like communication system. So in that sense, it would favor the idea that singing could have evolved prior to language or independently from language. And he says because the coordination of human singing is much more complex than lemur songs, studying it could provide a glimpse into what early human singing may have been like.

Thank you so much, Burley. I will never be able to listen to Lemurs or Queen the same way again. Same, Aaron. Same. This episode was reported and produced by me, Burley McCoy, edited by Giselle Grayson, who is also our senior supervising editor, and fact-checked by Catherine Seifer. The audio engineer was Josh Newell. Neil Carruth is our senior director of On-demand news programming,

and Anya Grunman is our... senior vice president of programming. I'm Aaron Scott. And I'm Burley McCoy. Thank you for listening to Shortwave, the Daily Science Podcast from NPR.