Researchers say their study shows cultural transmission not unique to humans
By Summit Voice
SUMMIT COUNTY — Humpback whale songs change over time, and move across oceans in distinctive patterns, according to Australian researchers, who recently published their findings in the online journal, Current Biology.
At any given time within a population, male humpbacks all sing the same mating tune. But as the pattern changes, catchy versions of the song spread across the ocean, almost always traveling from west to east.
“Our findings reveal cultural change on a vast scale,” said researchers Ellen Garland. Multiple songs moved like “cultural ripples from one population to another, causing all males to change their song to a new version.” This is the first time that such broad-scale and population-wide cultural exchange has been documented in any species other than humans, Garland added. Listen to some humpback whale songs documented by the researchers here.
The University of Queensland researchers collaborated with members of the South Pacific Whale Research Consortium and made the discovery by searching for patterns in whale songs recorded from six neighboring populations in the Pacific Ocean over a decade. This revealed a striking pattern of cultural transmission as whale songs spread from Australia to French Polynesia over the course of about two years.
“The songs started in the population that migrates along the eastern coast of Australia and then moved — just the songs, and probably not the whales — all the way to French Polynesia in the east,” Garland said. “Songs were first learned from males in the west and then subsequently learned in a stepwise fashion repeatedly across the vast region.”
In fact, only one song ever moved to the west over the period of the study. Garland explained that the almost exclusive movement of songs to the east may be due to population size differences, because the population on the east coast of Australia is very large compared to all others in the area. The researchers suspect that a small number of males move to other populations, taking their songs with them.
Alternately, whales in nearby populations hear the new songs while they swim together on migration.
Most of the time, songs contain some material from the previous year blended with something new. “It would be like splicing an old Beatles song with U2,” Garland said. “Occasionally they completely throw the current song out the window and start singing a brand new song.”
Once a new song emerges, all the males seem to rapidly change their tune. Those songs generally rise to the “top of the chart” in the course of one breeding season and typically take over by the end of it.
Garland said it is not yet known why the humpbacks’ songs spread in this way. In fact, why whales sing in the first place isn’t fully known. Song is likely a mating display, but it is unclear whether the main effect is to attract females or to repel rival males.
Still, Garland suspects that the whales may want to stand out like a new pop song. “We think this male quest for song novelty is in the hope of being that little bit different and perhaps more attractive to the opposite sex,” she said. “This is then countered by the urge to sing the same tune, by the need to conform.”
Filed under: biodiversity, Environment, Marine biology Tagged: | Current Biology, Environment, French Polynesia, Humpback whale, humpback whales, marine biology, Pacific Ocean, Summit County News, University of Queensland, Whale song