At Perth Canyon off Western Australia, pygmy blue whales leave a sound trail that changes with the hour: researchers recorded more of their songs at night than during daylight during the feeding season. The pattern may help scientists work out when these endangered whales are feeding, even when they cannot see them.
Pygmy blue whales feed on krill, and the new research suggests they generally do so during daylight hours. Singing was more common at night, when the whales had more time available for it. Across Perth Canyon, the difference between night and day song levels continued for up to three months during the whales’ feeding season.
The study was led by Curtin University researchers and published in Royal Society Open Science. The team examined singing and feeding behavior in offshore waters around Perth Canyon, along Western Australia’s Midwest coast, and farther north toward Ningaloo and the Northwest Shelf. Rather than relying only on direct sightings of whales, researchers may be able to use changes in song as a clue to feeding activity across broad stretches of ocean.
Lead author Andrew Davenport, a Ph.D. candidate at Curtin’s Center for Marine Science and Technology, said the link between feeding and singing offers a new way to understand this endangered population. “Just as we can't talk while we're eating, pygmy blue whales appear to have less time available to sing while they're feeding,” he said. By comparing when songs are heard more often at night than during the day, researchers can infer when whales in an area are likely to be feeding.
That matters because whales move through offshore waters where watching them directly can be difficult. Listening could give scientists another way to follow their behavior over large areas and build a clearer picture of when and where feeding takes place. The research does not mean that every change in song marks a meal, but it points to a useful pattern that can support monitoring.
The work focuses on a population already at risk, making better ways to track its behavior valuable for conservation. Acoustic monitoring—the use of recorded sounds to study animals—could help researchers gather information without needing to be beside the whales. The study offers a starting point for using day-and-night differences in song to understand feeding patterns across the whales’ range.
The findings were reported in the 2026 paper “Pygmy blue whale feeding drives greater nocturnal than diurnal song production,” by Andrew M. Davenport and colleagues. As researchers continue to listen across Western Australia’s offshore waters, whale song may help fill in parts of the daily lives of these elusive animals and provide evidence that can inform future conservation work.