The simple clicking communication of sperm whales is full of subtle variations and embellishments

Mutual communication between sperm whales appears to be very rich and diverse. These social marine mammals use fixed sequences of clicking sounds, the previously studied “coda.” But it now appears that they often change these apparently uniform sequences, depending on the context. American biologists and computer scientists write this in Nature Communications.

Sperm whales are known for their good cooperative skills, especially when it comes to collecting food. They dive to great depths to eat their favorite meal – squid – and between those dives they exchange patterned sequences of 3 to 40 successive clicks. Previous research has already shown that there are at least 150 such codas. But, as the authors emphasize in the current article, there was a contradiction between the socially complex behavior of sperm whales and the apparent simplicity of a communication system consisting only of a fixed repertoire of clicks.

Between 2005 and 2018, researchers recorded 8,719 kuda in the Caribbean Sea, west of the island of Dominica. They analyzed this computationally based on, among other things, the time between individual clicks. In doing so, they discovered that click durations within a single coda can vary in length. Researchers call such a temporary difference in rhythm a rubato (plus a coda, a term that will sound familiar to classical music fans) and it appears to be imitated by interlocutors in a single conversation with a sperm whale. If sperm whale A uses rubato, then sperm whale B in principle uses it as well. Sometimes an “ornament” is added: an extra click at the end of the standard coda. These motifs are especially common at the beginning and end of whale conversations. The rhythms and cadences of the entire coda are not dependent on context and can vary from sperm whale to sperm whale.

This creates a complete “sperm whale phonetic alphabet” of sperm whale sounds, which the researchers compare to the International Phonetic Alphabet of human languages. But while pronunciation and intonation play a major role in that alphabet, the crucial elements in sperm whales are the rhythms, rhythms, and any flourishes and decorations. As in human language, some patterns are more common than others and certain sequences do not occur at all. The way it is used in communication also varies. Sometimes sperm whales talk to each other (their vocal syllables overlap), and sometimes they take turns vocalizing.

Hopefully, the researchers write at the end of their article, a better understanding of sperm whale language can eventually contribute to deciphering that language. In some organisms, such as honeybees, the assembled parts of their code language explicitly contain information about, for example, the distance to a food source. In sperm whale language, rhythms, rhythms, rubatos, and ornamentations can play a similar role.

To participate





Email the editor