of the whale songs
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For male humpback whales, singing is serious business. Their haunting, complex songs can last for hours and travel for miles underwater, playing a central role in reproduction during the winter breeding season. But despite decades of research into what these songs sound like, scientists have had far less insight into what the whales are physically doing while they sing. Understanding that connection could reveal how singing affects a whale's energy use, oxygen management and vulnerability to underwater noise and vessel strikes.
A new study by Julia Zeh, a Ph.D. graduate in Syracuse University's College of Arts and Sciences (A&S) and member of biology professor Susan Parks' Bioacoustics and Behavioral Ecology Lab , reveals a previously unknown link between the structure of a humpback whale's song and the whale's movement through the water. Published in Current Biology [DB1] , the research shows that specific song themes are tied to specific parts of a dive, offering a new window into the biology and evolution of one of the animal kingdom's most elaborate acoustic displays.
Eavesdropping on a Whale's Playlist
To gather the data, Zeh and her collaborators temporarily attached sound-and-movement recording tags to singing humpback whales off the coast of Maui, part of a research effort spanning 2018 to 2024. The non-invasive tags are small suction-cup devices about the size of a tablet. Researchers attached them from small boats using long poles and, more recently, drones.
Once affixed, the tags recorded both the whale's underwater sounds and its movement before eventually losing suction and detaching, allowing researchers to retrieve the devices and download the data. In total, the team tagged 16 whales, a substantial sample from a tagging perspective and one selected to be broadly representative of the larger Hawaiian breeding population.
The team was surprised to find that some whales repeated their songs continuously for up to 16 hours without stopping. More importantly, recurring song elements known as themes lined up consistently with specific portions of a dive. While earlier researchers had noticed that certain themes tended to appear as a whale approached the surface, no one had previously connected an entire song structure to an entire dive cycle.
What the Songs Reveal
The connection between song and depth points to something deeper than coincidence. According to Zeh, themes sung while whales remained at a relatively constant depth during the deepest part of a dive showed different levels of variability than themes sung elsewhere, suggesting those sections may be more strongly shaped by sexual selection. This means they could serve as signals of a male's individual quality. Themes tied to other parts of the dive, by contrast, may be constrained by physiological or environmental factors, such as the demands of managing oxygen and buoyancy while singing.
"This gives us direction for which parts of the song to investigate if we're interested in variation, which is likely driven by sexual selection," Zeh says, noting that variation concentrated near a whale's deepest points in the water column may be where a male's song is doing the most work to stand out.
The findings also have practical applications. Because acoustic monitoring is already a common tool for tracking whale populations, understanding how song relates to movement could allow researchers to determine a whale's depth or position directly from a recording. That, in turn, could help scientists establish a clearer baseline for normal humpback behavior, an essential reference point for detecting when whales are disturbed by human activity such as vessel traffic or ocean noise.
Whether the same patterns hold for humpback populations outside Hawaii remains an open question. Zeh notes that while she would expect similar physiological constraints to apply broadly, documented differences in song evolution between hemispheres raise the possibility that different populations experience different pressures on song structure. Testing that would mean collecting comparable tag data from singing whales on breeding grounds around the world.
A Foundation Built in the Field
The research reflects years of fieldwork and analysis carried out during Zeh's doctoral studies in Parks' lab at Syracuse, where she focused on the intersection of animal behavior, acoustics and marine biology. Her time in the lab gave her the tools to combine bioacoustic analysis with biologging technology in a way that had not previously been applied to humpback whale song, allowing her to ask new questions about a subject long studied primarily through sound alone.
By reframing whale song through the lens of movement, Zeh's work opens a new avenue for studying how physiology, environment and the social transmission of song interact to shape one of nature's most complex learned behaviors. It also offers a model that researchers can apply not only to future humpback studies, but potentially to the study of complex acoustic communication across species.
"My time at Syracuse changed the way I think about what's possible in this field," Zeh says. "Projects like this one, where we combined acoustics with movement data, gave me the tools to ask exciting questions about whale behavior and the opportunity to be creative in how we look at well-studied phenomena like humpback whale song. These experiences inform how I conduct research and have given me the foundation for my current work in ecological monitoring and conservation."
Since completing her doctoral studies at Syracuse University, Zeh finished a postdoctoral appointment with the Passive Acoustics Branch at NOAA's Northeast Fisheries Science Center in Woods Hole, Massachusetts. She now leads the Archival Passive Acoustic Monitoring Team at the Maine Department of Marine Resources in West Boothbay.
