Humpback whales have long been admired for their intelligence, and their behaviour around other marine creatures has been extensively observed and documented.

In particular, the whales’ habit of teaming up to blow bubbles and form a ring around a school of small fish to ‘corral’ them and make feeding easier. This hunting collaboration has raised interesting speculation about the nature of communication between team members.

In 2021, a team of scientists from the SETI Institute conducted what was termed a ‘conversation’ with a single humpback named Twain. This consisted of playing whale calls through an underwater speaker that Twain responded to with similar calls.

Later, in a 2024 study by the same group, whale calls made during bubble feeding events, originally thought to be random and purposeless apart, perhaps, from being a way to keep in touch with other members of the pod, were surmised to have more specific objectives. Certain calls seemed to be a way of the whales issuing instructions or making targeted comments to the group.

But these studies did not touch on humpback whales’ voluntary interactions with humans, rather than contact engineered by the researchers, or their use of bubble blowing, other than as a hunting strategy.

A new study by the scientists from SETI and the University of California, published in Marine Mammal Science, has addressed both these aspects of whale behaviour and documented humpbacks producing large bubble rings during friendly encounters with humans that seem to be an attempt at sending messages.

The SETI Institute’s overall purpose is to understand the origins and prevalence of life and intelligence in the universe so these interactions aroused great interest. Non-verbal communications, as well as attempts at speech, wherever they occur, are seen as key to furthering our understanding of all life forms. This applies to non-human species currently on Earth as well as to any sentient beings that might be encountered in the future, if space exploration brings us in communication contact with life forms on other planets.

“Humpback whales live in complex societies, are acoustically diverse, use bubble tools and assist other species being harassed by predators,” says co-lead author Dr Fred Sharpe. “Now, akin to a candidate signal, we show they are blowing bubble rings in our direction in an apparent attempt to playfully interact, observe our response, and/or engage in some form of communication.”

A candidate signal is the name given to interesting radio waves that can be detected from the depths of space, that have been the subject of much analysis as to their origin and meaning. The team likened what they see as these attempts at communication on the part of the whales, and the efforts researchers are making to understand their bubble messages, as akin to the work being done to interpret interplanetary radio signals.

The study analysed 12 bubble ring-production episodes involving 39 rings made by 11 individual whales. “We’ve now located a dozen whales from populations around the world, the majority of which have voluntarily approached boats and swimmers blowing bubble rings during these episodes of curious behaviour,” said co-lead author Jodi Frediani, a marine wildlife photographer.

The Whale-SETI team aims to use the results of their research to develop filters that aid in parsing cosmic signals for signs of extra-terrestrial life. They hope that with continued observation and the help of AI they may in the future be able to accurately interpret the communications, verbal and non-verbal, of whales and other animals. These learnings and techniques could then be applied to communications coming from outside our world.

Listen to the sounds of bubble-making whale pack