Humpback whales sing highly complex songs, but science is starting to explore how they work. Photo: Supplied: Operation Cetaces
Most of us are familiar with whale song, but new research suggests that the structure of the song - the individual parts that make up the whole - has similarities to human language.
While we don't know what the songs mean, the distinct patterns mirror the way that humans communicate.
Dr Emma Carroll is a marine biologist from the University of Auckland.
Working with several other researchers, the study analysed the groans, moans, whistles, barks, shrieks and squeaks in humpback whale song recordings collected over eight years in New Caledonia.
"I've always been fascinated by the kind of complex cultural behaviours that whales show, and particularly how that influenced their recovery from whaling," Carroll told Afternoons' Jesse Mulligan.
Carroll has done a lot of research on southern right whales and their migratory culture, which helped them bounce back from the toll of whaling. Their babies will travel with them for their first year of life and learn about feeding grounds and ocean currents.
"The migratory tradition is a simple form of culture," she said.
"To me, culture is information or behaviour that is shared within a group."
Dr Emma Carroll, a marine biologist at Waipapa Taumata Rau, University of Auckland. Photo: Supplied / University of Auckland
But why do whales sing in the first place?
"In general, if you think about the marine environment, you can't see for more than a couple of hundred metres and if you go deeper you can't see that far at all.
"So, acoustic communication is a really powerful way of communicating across vast distances in the ocean. So that could be as simple as 'I'm here, where are you,' or it could be these really complex displays like we see in humpback whales."
Whale songs by the blue whale, the largest animal on earth, can travel for hundreds of kilometres.
"It depends on how big the animal is, the frequency."
What scientists do to better study the sound is create a visualisation of them.
"It's very difficult" to study them, Carroll said.
"In a population, all males sing the same song, but that song will change from year to year.
"But to be able to understand that, you need to first record the song. And to do that, you have to find the singing whales.
"And by definition, they're underwater singing, and so you have to be very patient and wait for them to come to the surface. They mainly do a couple of breaths every half an hour to hour.
"They're very busy, underwater, doing their thing, and you just have to be lucky and patient."
Once the sounds have been recorded, scientists look for the structure.
"Each song may be five minutes or half an hour, and there's elements within it.
"So there's things like moans and grunts. ... We can characterise and describe them within a sequence.
"And if we think that human language, it's similar, we're speaking in sequences, but we're obviously not saying that we know the meaning of those sequences in whale songs, purely about the structure.
"So what we did is we took the whale songs, and so for example if you have a moan, a grunt and a grunt, you look at that transitional probability from grunt to grunt, for example.
"And we did this because in human language, when babies start to try and understand human language, they use statistical properties of that language, and that's about transitional properties."
Across human languages, the most used word appears about twice as often as the second most common word, three times as much as the third most common word and so on, the study's research found.
Dividing the whale song into segments, the researchers found the same rules of frequency and brevity apply.
"We created a bunch of whale song segments and so we looked at these different segments and how common they were in each year of whale song recording," Carroll said.
"The really cool thing was the kind of pattern of segmentation, it follows what's called Zipfian distribution, but all that's saying is it has the characteristics that are found in human language that essentially makes it predictable.
"So you can start to pull out those more common sound elements that form the bulk of, in our case, language, but in the case of the whales, the song.
"So if I give you an example from English, if you think about common words, there's things like 'a, the, in,' they're very common but they're very short, and it's the same with whale songs.
"The more common elements are also very short. So what that does it is it helps make it predictable, and it helps make it easier to learn."
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
