Scientists document unusual ‘phonetic alphabet’ of sperm whales

Scientists document unusual ‘phonetic alphabet’ of sperm whales

The various species of whales that inhabit the Earth’s oceans use different types of vocalizations to communicate. Sperm whales, the largest of the toothed whales, communicate using clicking sounds – called codas – that sound like Morse code.

A new analysis of years of vocalizations by sperm whales in the eastern Caribbean has found that their communication system is more sophisticated than previously known, exhibiting a complex internal structure full of “phonetic alphabets.” The researchers identified similarities with aspects of other animal communication systems – and even human language. Like all marine mammals, sperm whales are highly social animals, with their calls being a part of this.

This new study has provided a more complete understanding of how these whales communicate. “Research shows that the expressiveness of sperm whale calls is much greater than previously thought,” says Pratyusha.

Sharma, a Massachusetts Institute of Technology doctoral student in robotics and machine learning and lead author of a study published Tuesday in the journal Nature Communications. “We don’t know what they’re saying yet. We’re studying the calls in the context of their subsequent behavior to understand what sperm whales might be communicating,” Sharma said.

Sperm whales, which can reach about 60 feet (18 meters) in length, have the largest brains of any animal. They are deep divers, feeding on giant squid and other prey. The researchers are part of the CETI (Cetacean Translation Initiative) Project Machine Learning Team.

Using traditional statistical analysis and artificial intelligence, they examined the calls made by about 60 whales recorded by the Dominica Sperm Whale Project, a research program that has collected

dataset on species. “Why are they exchanging these codas? What information might they be sharing?” asked study co-author Shane Gero, lead biologist for Project CETI and founder of the Dominica Sperm Whale Project, also affiliated with Carleton University in Canada. “I think it’s possible that they use coda to coordinate as a family, organize childcare, forage and defense,” Gero said. Variations in the number, rhythm and tempo of clicks produce different types of coda, the researchers found.

Popes, among other things, change the duration of the coda and sometimes add an extra click at the end, like a suffix in human language. “All the different codas we see are actually constructed

by putting together relatively simple sets of small pieces,” said study co-author Jacob Andreas, an MIT computer science professor and Project CETI member. People combine sounds – often corresponding to letters of the alphabet – to produce words that carry meaning, then produce word strings to create sentences to convey a more complex meaning.

As for the public, Sharma says, “There are two levels of affiliation.” The bottom level is sound to words. The higher level is word to sentence. Sperm whales, Sharma said, also use a combination of two levels of features to form codas, and the codas are then put together as the whales communicate. The lower levels have similarities to letters in the alphabet, Sharma said. “Each communication system is adapted to the environment and animal society in which it has evolved,” added Sharma. The communication system used by sperm whales differs, for example, from the “song” of humpback whales – and, for that matter

things, from whistles, chirps, croaks and various other vocalizations by various animals. “Human language is unique in many ways, yes,” says Gero.

“But I suspect we’ll find many patterns, structures and aspects thought to be unique to humans in other species, including whales, as science progresses – and perhaps even features and aspects of animal communication that humans don’t.”

If scientists can decipher what sperm whales “speak,” should people try to communicate with them? “I think there’s a lot more research we need to do before we know if it’s a good idea to try to communicate with them, or really to find out if that’s possible,” Andreas said.

“At the same time, I’m optimistic that we’ll be able to learn a lot more about the information that’s actually encoded in these vocalizations that we’re hearing, the kind of information contained in these clicks and these codas, as we begin to understand the behavioral context in which this happened,” added Andreas.