Contextual and combinatorial structure in sperm whale vocalisations

"The researchers identified something of a "sperm whale phonetic alphabet," where various elements that researchers call "rhythm," "tempo," "rubato," and "ornamentation" interplay to form a vast array of distinguishable codas. For example, the whales would systematically modulate certain aspects of their codas based on the conversational context, such as smoothly varying the duration of the calls—rubato—or adding extra ornamental clicks. But even more remarkably, they found that the basic building blocks of these codas could be combined in a combinatorial fashion, allowing the whales to construct a vast repertoire of distinct vocalizations.

The experiments were conducted using acoustic bio-logging tags (specifically something called "D-tags") deployed on whales from the Eastern Caribbean clan. These tags captured the intricate details of the whales' vocal patterns. By developing new visualization and data analysis techniques, the CSAIL researchers found that individual sperm whales could emit various coda patterns in long exchanges, not just repeats of the same coda. These patterns, they say, are nuanced and include fine-grained variations that other whales also produce and recognize."