Algorithms designed to decode the phonetic alphabet used by sperm whales has revealed a communication system far more intricate than had previously been appreciated.
A team of researchers have discovered that it contains sophisticated structures akin to human phonetics and communication systems in other animal species – and believe that deciphering the language could prove helpful should extra-terrestrials ever decide to contact the human race.
Sperm whales have the biggest brains of any known animal, and their complex social behaviour calls for strong communication to aid their co-ordination especially under pressure, as when deep-sea hunting.
The scientific team from the Massachusetts Institute of Technology’s Computer Science & Artificial Intelligence Laboratory (CSAIL) and Project CETI (Cetacean Translation Initiative) have found that the whales’ ‘codas’ – the short bursts of clicks they use to communicate – vary significantly in structure depending on the conversational context.
Their starting point was 9,000 of these codas collected from Eastern Caribbean sperm whale families that had been under observation by the Dominica Sperm Whale Project.
Combining this data with algorithms to recognise and classify patterns as well as on-body recording equipment, the researchers were able to identify a sperm whale’s phonetic alphabet, and then to categorise various elements as ‘rhythm’, ‘tempo’, ‘rubato’ or ‘ornamentation’, interplayed to form an array of distinguishable codas.
The whales would systematically modulate aspects of their codas based on the conversational context. Examples included varying the duration of the calls (rubato) or adding extra ornamental clicks, combining these elements to provide a “vast repertoire” of distinct vocalisations.
Mysterious alphabet
When acoustic bio-logging tags were fitted to the Eastern Caribbean whales to capture their nuanced vocal patterns, individuals were found not simply to repeat codas but to emit a variety of coda patterns in long exchanges.
“We are venturing into the unknown, to decipher the mysteries of sperm whale communication without any pre-existing ground truth data [data required for AI applications],” says CSAIL director Daniela Rus, a professor at MIT. “Using machine learning is important for identifying the features of their communications and predicting what they say next.
“Our findings indicate the presence of structured information content and also challenges the prevailing belief among many linguists that complex communication is unique to humans.
“This is a step toward showing that other species have levels of communication complexity that have not been identified so far, deeply connected to behaviour.
“Our next steps aim to decipher the meaning behind these communications and explore the societal-level correlations between what is being said and group actions.”
And the team have their sights set not only on oceanic but possibly extra-terrestrial communications. “Our work could lay the groundwork for deciphering how an ‘alien civilisation’ might communicate, providing insights into creating algorithms or systems to understand entirely unfamiliar forms of communication,” says the study’s lead author, MIT PhD student Pratyusha Sharma.
The open-access study is published in Nature Communications.
Also read: Sperm Whales: The Enigmatic Giants of the Deep, The Sperm Whales Dominica
