What are whales saying to each other? Scientists are a step closer to finding out

Scientists have examined thousands of hours of sperm whale calls — bursts of clicks known as codas — and discovered a kind of phonetic alphabet that the animals use to communicate.

"What we've done here is really sort of expand … the library of potential codas that these animals are using," said Shane Gero, a scientist-in-residence at Ottawa's Carleton University and biology lead at Project CETI, a non-profit that studies sperm whale communication.

"[They're] sort of building block parts, that they can combine in various different ways, freely, to make many, many, many more kinds of codas than we thought before," he told The Current.

Gero is co-author of the study, which was published last week in Nature Communications. The researchers used artificial intelligence to crunch thousands of calls from about 60 sperm whales, recorded over 15 years off the Caribbean island of Dominica. Those calls were recorded by devices mounted on the backs of the whales, gathering audio as well as contextual data like the location, time of day, and even ocean temperature.

The findings are a step towards potentially one day decoding what whales are saying to each other — though Gero emphasized that's still a long way off, if possible at all.

In the published paper, the researchers describe codas as "the basic units of sperm whale communication." A coda contains of multiple clicks — sounding a little like Morse code — but is generally less than two seconds in duration. While researchers previously already knew that each coda can vary in rhythm and tempo, Gero said this new research adds two new ideas: rubato and ornamentation.

Rubato refers to an alteration in the duration of the calls, while Gero said ornamentation is where the whales will add an extra click to a coda. (Both terms, like coda, also appear in musical terminology.)

"There's some indication that it happens around turn taking, so when one animal stops and another animal starts," he said.

"We've been jokingly saying that it's like the Canadians adding 'eh?' to the end of everything."

Diana Reiss, a marine mammal behaviour and communication expert at the City University of New York, told The Associated Press that scientists understand some marine animal communication reasonably well, including the whistles used by dolphins and the songs sung by humpback whales. But our understanding of sperm whale communication is much more limited.

"What's new in this study is that they are trying to look at the basis for the whales' communication system ... not just particular calls they're making," said Reiss, who was not involved in the study. 

Gero said the findings don't point to something like the 26 letters in the English alphabet, and should be thought of more as phonemes, the "different building block sounds" that can be combined into distinct codas. 

"Those codas then get exchanged in long sequences that we call exchanges or choruses," he said.

Gero noted that humans and whales alike are social animals, who prioritize family ties and support each other with caring for the young.