UC Berkeley and Project CETI study shows sperm whales communicate in ways similar to humans

The way sperm whales communicate may be more similar to human language than previously thought. The acoustic properties of whale calls resemble vowels, a defining feature of human language, according to a new study from UC Berkeley's Linguistics Department and Project CETI (Cetacean Translation Initiative). These findings could revolutionize our understanding of the animal world.

"In the past, researchers thought of whale communication as a kind of morse code," said Berkeley Linguistics Professor Gašper Beguš, who is the linguistics lead at Project CETI. "However, this paper shows that their calls are more like very, very slow vowels. This suggests a complexity that approaches human language."

The study, titled "Vowel- and Diphthong-like Spectral Patterns in Sperm Whale Codas(link is external)," discovered two distinct patterns, an ɑ-vowel and an i-vowel, and several diphthong-like patterns, in whale communication. Beguš, who led the study, said that sperm whales exchange these vowels and diphthongs with each other in what seems to resemble a dialogue.

"The whales' production of the ɑ-vowel, i-vowel and diphthongs is likely controlled," Beguš said. "This is true across almost all whales. We don't understand the meaning yet, but we know that whales produce these sounds intentionally and we know that they differentiate between them."

This study is part of an ongoing research initiative carried out by Project CETI, a large team of leading artificial intelligence researchers, marine biologists, cryptographers, roboticists and underwater acousticians attempting to understand how sperm whales communicate.

These acoustic properties of sperm whales share substantial similarities with human vowels, according to Beguš, adding that vowels in human speech can differ in length, timing, frequency and trajectory. The research shows that whale vowels feature these same characteristics. In human language, these characteristics carry meaning. It's possible that the same is true for sperm whales, Beguš explained.

"The spectral properties we discovered are very similar to human vowels. They correspond so closely that we can use human letters to describe them," Beguš said. "Even the production of those sounds, which mirrors human vocal tract pulses, is similar to humans."

The findings are a breakthrough in decoding sperm whale communication. However, their implications go beyond just translation. According to Beguš, understanding that sperm whales may have the capacity for language raises serious legal and ethical questions.

"We're thinking deeply about what finding these human-like structures means for the legal rights of animals," said Beguš. "This paper prompts questions like, for example, what is language? Is there anything uniquely human about language, or is it just a continuum? What does that mean for the law?"

By questioning long-standing beliefs about animal communication, according to Project CETI, this research could pave the way toward rethinking the moral and legal distinctions separating humans and animals. Beguš is confident that taking steps toward deciphering whale communication has the capability to aid both conservation efforts and the animal rights movement.

The broader goal of Project CETI is to translate the communication of sperm whales. Project CETI has spent the last five years observing sperm whale communication and behaviors through the use of tags, buoys, aquatic drones and aerial drones. In recent years, they've finally begun to learn how their calls are used for communication.

To analyze the acoustic properties of whale calls, Beguš used generative adversarial networks (GANs), a machine learning model that identifies patterns in existing datasets. Similar to human children, GANs learn languages by listening and imitating. This technology makes it possible to learn about the structure and meaning of animal communication.

"GANs can discover words and meaningful structure. When designing the model, we asked whether they could do that in whales as well," Beguš said. "We still need human researchers to analyze the details, but they help us look in a specific direction."

Using these techniques, Beguš and other linguists analyzed sperm whale vowels and vowel combinations called diphthongs. This is in contrast to previous research, which primarily focused on whale clicks, or high-frequency pulses, and the timing between them. For instance, Project CETI previously discovered 156 click patterns that make up the whales' sound system.

"Before, researchers focused primarily on whale clicks and inter-click timing," said Beguš. "Analyzing vowels adds a completely new dimension that brings much more complexity."

The work being done at Project CETI is also transforming the field of linguistics. According to Beguš, this study opens up the potential to apply linguistics to animal communication. This positions linguistics at a crossroads with biology in a way that could reshape our understanding of language and life itself.

"This work is so important because it helps you relativize your own position as a human," said Beguš. "We exchange inner worlds through speech, through vowels and consonants. This is a small step towards understanding the inner worlds of animals, their cultures and their intelligences."