Sperm whales (Physeter macrocephalus) are highly social mammals that communicate using clicks. According to new research, they can combine and modulate different clicks and rhythms to create complex calls, similar to human language.
Sperm whales (Physeter macrocephalus). Image credit: Gabriel Barathieu / CC BY-SA 2.0 Deed.
Communication is important for social animals to help them to make group decisions and coordinate joint tasks, such as foraging and rearing young.
Sperm whales are sociable mammals that communicate with each other using sequences of clicks.
While some of their clicks have previously been shown to communicate their identity, little else is known about the sperm whale communication system.
“Cetaceans are an important group for the study of evolution and development of sophisticated communication systems,” said MIT researcher Pratyusha Sharma and colleagues.
“Among cetaceans, long-term observational studies of sperm whales have described both a culturally defined, multi-level, matrilineal society and a socially transmitted communication system.”
“Sperm whales are known for complex social and foraging behavior, as well as group decision-making.”
“They communicate using codas: stereotyped sequences of 3-40 broadband clicks. Codas are exchanged between whales when socialising or between long, deep, foraging dives.”
For the study, the authors used the annotated coda dataset from the Dominica Sperm Whale Project, the largest repository of sperm whale data.
They analyzed recordings from about 60 different whales from the Eastern Caribbean sperm whale clan and use them to define a ‘sperm whale phonetic alphabet’ of click combinations from recordings of this clan.
They found that the whales’ communication system is more complex and has a greater information-carrying capacity than previously thought.
The combination and structure of the click sequences produced was found to depend on the conversational context of the individuals.
The scientists also identified a ‘combinatorial structure’ to their language, where the whales can combine and modulate different clicks and rhythms to create complex vocalizations, similar to human language.
“While the function and meaning of the click combinations is still unknown, sperm whale language is potentially capable of representing a large number of possible meanings,” they said.
Their paper was published in the journal Nature Communications.
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P. Sharma et al. 2024. Contextual and combinatorial structure in sperm whale vocalisations. Nat Commun 15, 3617; doi: 10.1038/s41467-024-47221-8
