Study provides most detailed analysis yet of how baleen whales produce sound

MARY LOUISE KELLY, HOST:

You might recognize this song.

(SOUNDBITE OF HUMPBACK WHALE SINGING)

KELLY: It's the song of a humpback whale, a type of baleen whale.

COEN ELEMANS: All the baleen whales make extremely low frequency sounds, and it sounds like a bit like humming, like, (imitating whale sound), something like this. And it's really hard for me to do because I'm very little compared to a whale.

AILSA CHANG, HOST:

(Laughter) Coen Elemans is at the University of Southern Denmark, and he and his colleagues were curious how whales make these iconic sounds, which until recently, scientists knew very little about because it's quite hard to get your hands on the larynx of a whale. Many species are endangered or protected.

ELEMANS: So the only way we can work with these animals now, on the physiology, is if one accidentally dies.

KELLY: If it beaches, for example. But you have to act fast when that happens.

ELEMANS: What happens then is that these whales start rotting. And they rot so incredibly fast that they're actually known to explode on the beach.

KELLY: In 2018, though, Elemans got his chance when a whale died in northern Denmark. A colleague called him on a Sunday night. He was on vacation.

ELEMANS: I got a phone call from him. It was like, a whale just beached. We have to get the larynx out tomorrow. So the next morning, we basically were on the coast, and we're doing a dissection of a sei whale.

CHANG: He and his team collected two more whale larynxes over the years. They then built an apparatus in the lab with a party balloon standing in for a whale's lungs. And they used that to blow air through the larynxes.

(SOUNDBITE OF LOW NOTE)

ELEMANS: And as such, we can basically see which parts are vibrating, but then also measure the vibration with different techniques.

KELLY: They also built a computer model of one of the larynxes to study how a living whale might use its muscles to manipulate its calls. And the scientists found that baleen whales use airflow to vibrate tissue and produce sound very similar to how we humans do it.

ELEMANS: What's very different is the location and the structures that make the sound in the baleen whales. And that's completely novel structures that, as far as we know now, no other animal has.

KELLY: The details are in the journal Nature.

CHANG: And whereas singers like Mariah Carey can produce a huge range of pitches with their voices, this study found that whales cannot.

KELLY: Which is a problem because the sounds of human machinery and boats happen to rumble around the same frequency as these whales. Elemans suggests maybe humans could be a little more considerate?

ELEMANS: We can start to plan this and say, we only make noises in these areas when the animals are not there.

CHANG: Allowing the whales a chance to carry on with their songs.

(SOUNDBITE OF ALGAL'S "THE WELLERMAN (INSTRUMENTAL)") Transcript provided by NPR, Copyright NPR.