New Research Reveals Language-Like Structure in Whale Song

New research from an interdisciplinary group of academics, including Dr Ellen Garland from the University of St Andrews, has discovered a new structure in whale song: a structure shared in human languages. The study highlights that certain aspects of our own languages, previously thought to be unique to our species, are present elsewhere in the natural world. Significantly, the team discovered that whale song is a culturally transmitted communication system and is therefore not an instinctive behaviour. Like human language, whales must learn their song from each other.

The team used an innovative method inspired by the way babies learn languages to uncover the hidden structure of whale song. Dr Garland expanded on this process, “There are no pauses between words, so infants have to discover word boundaries.” The process characterises the key challenge of learning a language: knowing where one word ends and another begins. Just as infants use “low-level statistical information” to understand these boundaries, so did the research team use the statistical structure of whale song to divide its distinct elements. “We used the exact same cue that infants use to segment the whale song,” explained Dr Garland.

The process was applied to eight years’ worth of humpback whale songs recorded in New Caledonia. Researchers “calculated the transitional probabilities between each two consecutive sound elements,” according to Dr Garland, and marked divides “when the next sound element was surprising given the previous one.” Through this technique, the whale song was successfully cut into sub-sequences. After analysing this dataset, it was discovered that “they follow the same distribution found across all human languages.”

Dr Inbal Arnon, who works for the Language Learning and Processing Lab at the Hebrew University, noted that whale song data followed “a particular power law distribution found in all human languages.” This refers to ‘Zipf’s Law’, an empirical principle that has notably been applied to languages. In this context, it reveals that the most common word in a language appears twice as frequently as the second most common, and so on. While this law has been known to be true for most human languages, its relevance for whale song is a novel revelation.

Dr Arnon spoke on the implications of this finding, “Language is the way it is […] because of the way it is learned and transmitted over generations. This process creates learnability pressures […] which shape its structure.” By studying the communication style of these aquatic animals, the research has resulted in an increased understanding of the evolution of language itself.

However, whale song is not considered a language; Dr Garland made the important distinction that whale song “lacks semantic meaning.” Instead, she structurally compared it to music: “a culturally transmitted behaviour where individual ‘units’ do not have explicit expressive meaning and nevertheless show a good fit to a Zipfian distribution.” The meaning of whale song, as it were, relates to its function. Whale song is a male-only practice and is believed to be used for finding mates. The structure of this song “is suggested to aid in learning such a long, complex display.”

Both Dr Garland and Dr Arnon have stressed the importance of working with academics from a variety of fields in this project. “These novel findings could only have been discovered by a team of scientists from very different disciplines working together,” affirmed Dr Garland. Such a sentiment was echoed by Dr Arnon, who attested that “by integrating insights and methods from three very different fields: child language learning, language evolution, and whale song research,” the new structure in whale song was able to be discovered.

The findings of the study demand further investigation into the statistical structures of culturally transmitted communication systems. Dr Garland and Dr Arnon both suggest that songbirds likely display similar patterns of communication, and the investigation into whale song “opens up new research directions for investigating other species,” as Garland stated.

The study has enriched the appreciation and knowledge of humpback whales and their communication methods, alongside expanding understanding of the nature of languages.

Image by National Geographic