August 31, 2022 report
Humpback whale songs spread from pod to pod across the Pacific Ocean
A team of researchers with members from the University of St Andrews, Universidad San Francisco de Quito and the CETACEA Ecuador Project's Acoustic Ecology Program has found that songs created by humpback whales in some parts of the Pacific Ocean are mimicked by whales in other parts of the ocean. They have published their paper in the journal Royal Society Open Science.
Prior research has shown that humpback whales sing intricate songs—some of them are quite long, lasting up to 30 minutes. It is not known why the whales sing the songs, but oceanographers suspect they do so likely for the same reason that many birds, humans and other species sing—to attract a mate. In any case, the song sung by any given individual is shared by others in a pod, with very minor differences. But sometimes, bigger changes are made by an individual for unknown reasons. When that happens, the others in the pod make the same change.
Back in 1996, another team of researchers discovered that songs sung by one pod are sometimes copied by whales in a nearby pod. In this new effort, the researchers found that songs can be passed along from pod to pod, moving all the way across the Pacific Ocean.
The work involved recording humpback whale songs using a SoundTrap autonomous recorder over the years 2016 to 2018 at various sites around the Pacific, including following some pods in a boat. The researchers found that two pods (one in French Polynesia the other near Ecuador) had been singing two very different songs from one another from 2016 to 2017—but then in 2018, both pods were recorded singing the same song.
The researchers suggest their findings hint at the possibility of humpback whale songs migrating all the way across the Southern Hemisphere—though they note that they appear to propagate in just one direction, west to east. The researchers also suggest that it would seem unlikely that song migration is unique to humpbacks—they believe it likely happens in many other species, as well.
More information: Josephine N. Schulze et al, Humpback whale song revolutions continue to spread from the central into the eastern South Pacific, Royal Society Open Science (2022). DOI: 10.1098/rsos.220158
Journal information: Royal Society Open Science
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