For decades, scientists have marvelled at the haunting songs of humpback whales, but one question has remained largely unanswered: what are the whales actually doing while they sing? New findings, published in the journal Current Biology, suggest the answer lies beneath the surface. Scientists have found that different parts of a humpback whale’s song consistently match different stages of its dive, offering a new way to understand the animals’ behaviour and potentially improving efforts to protect them from threats such as vessel traffic and underwater noise. Songs and dives move in sync The research was led by Julia Zeh, who completed her PhD at Syracuse University, and tracked singing male humpback whales off the coast of Maui between 2018 and 2024. Researchers temporarily attached small suction-cup tags to 16 whales. The devices recorded both underwater sounds and the whales’ movements before detaching naturally, allowing the team to recover the data. The recordings revealed that some whales continued singing for as long as 16 hours. More significantly, recurring sections of their songs, known as themes, repeatedly occurred during the same phases of a dive. While earlier studies hinted that some song elements appeared as whales neared the surface, the new research is the first to connect an entire song structure to a complete dive cycle. Clues about communication and survival Researchers say the pattern may reveal more than simple timing. Song themes performed during the deepest, most level portion of a dive appeared to vary more between whales than themes sung during other stages. That suggests these sections could play a greater role in attracting mates, while other parts of the song may be shaped by physical demands such as managing oxygen levels and buoyancy underwater, the research said. According to the report, understanding those relationships could also have practical value. Because scientists already use underwater microphones to monitor whale populations, recognizing how songs correspond with diving behaviour may allow researchers to estimate a whale’s depth and activity, without needing to attach tracking devices. That could help establish what normal behaviour looks like and make it easier to detect when whales are being disturbed by shipping, ocean noise or other human activity. Researchers say future studies will determine whether whales in other parts of the world follow the same song-and-dive pattern, potentially revealing how humpback populations have adapted their vocal displays in different oceans.
