The sad melodies sung by humpback whales could indicate loneliness, according to scientists who monitored the animals in Australia. As the humpback whale population increased, the number of whales using their loud and far-reaching songs to attract mates decreased, as observed by marine biologist Rebecca Dunlop, who has been studying the humpback whales near the Great Barrier Reef for the past 20 years.
Rebecca Dunlop, a marine biologist from the University of Queensland in Brisbane, observed an unexpected phenomenon as whale populations significantly increased after the end of commercial whaling, which is considered one of the biggest triumphs in conservation history.
Humpback Courtship Song
According to Dunlop, it became increasingly challenging to locate humpback whales that were singing, which contradicted her earlier findings. She noted that when the number of whales was lower, there was a greater amount of singing to find a mate, whereas now that the population has grown, there is less need for whales to produce such songs.
In the 1970s, researchers were able to study the intricate songs of humpback whales using advanced underwater microphones. Male whales are the only ones that produce these tunes, and they are believed to serve a purpose in finding a mate and establishing dominance. At one point, the humpback whale population in Eastern Australia was on the brink of regional extinction, with approximately 200 whales remaining in the 1960s. However, the population grew significantly over time and reached nearly 27,000 whales by 2015, which is approaching the estimated levels before commercial whaling.
Following a report published in the journal Nature Communications Biology, the courtship behavior of humpback whales changed as their population density increased. In 2004, 2 out of 10 male whales were singers, but a decade later, that ratio decreased to only 1 out of 10. Marine biologist Rebecca Dunlop and her colleagues suggest that singing may have played a more significant role in attracting mates when the whale populations were severely depleted.
Humpback Attracting Techniques
As Dunlop explained, finding other whales in the area was challenging because of the low numbers. In contrast, when the population becomes denser, a male seeking a mate has to compete with other males, and singing may reveal their location to potential rivals. According to Boris Worm, a marine biologist from Dalhousie University in Canada who did not participate in the study, animal populations change their behavior as they recover, adapting to different limitations.
Nevertheless, the oceans are still a cacophony of sounds. As the Australian researchers noted, many humpback whales use a combination of physical jostling and singing to attract a mate. Simon Ingram, a marine biologist from the University of Plymouth in England who was not involved in the study, commented that the significant growth in whale populations during the study period offered a distinctive opportunity to observe changes in their behavior, as reported by Phys.
Simon Ingram also remarked that humpback whales have likely been using songs to attract mates for an extended period, even before commercial whaling reduced their population. The recent study, however, underscores the importance of their intricate and melodious songs in their survival and recovery. Ingram emphasized that singing became particularly valuable for these animals when their population was at its lowest point.
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