When a male humpback whale sings, it hangs its 40-foot-long, 40-ton body upside down in the water and makes some of the world’s most distinctive sounds. according to a study 2018 who analyzed the songs of Australian humpback whales, the whales share an ever-evolving language, like a local dialect, made up of “phrases” strung together to form “themes” that are then arranged to form songs. The shrieks and moans become more complex as the humpback whales add their own flourishes, similar to a folk singer changing a chorus.
While humpback singing is believed to have several purposes, perhaps one of the most important being to attract a mate, this majestic ritual may be in decline. TO new study of Australian humpback whales found that the huge mammals now often resort to fighting for love by charging and headbutting other potential suitors, among other tactics. Such battles tend to occur after a male has approached a female and is swimming alongside her, and others rush in to take her place, as documented in account of a writer of a fight of whale against whale.
Whaling and behavior change
The increase in courtship violence has a simple explanation, the researchers say: changes in humpback whale populations and the legacy of whaling.
Read more: Humpback whales go through a ‘cultural revolution’ every few years
Whaling wiped out most of the world’s humpback whales, leaving only about 200 individuals in the 1960s, and as the population improved, so did the density of males. And when males came into closer contact with each other, they were more likely to stop singing and gain mates through means other than singing, including head patting, the study found. While the song attracted the females, it also alerted the males, who sometimes tried to assert their dominance.
“Humans aren’t the only ones subject to big societal changes when it comes to mating rituals,” says lead researcher Associate Professor Rebecca Dunlop from the University of Queensland, in Press release.
The study presented a unique opportunity to study a population as it recovered from near extinction, using a wealth of data from 1997 to 2015. The researchers relied on a series of hydrophone buoys to record and signal the song of the whales, and combined that data with visual. Observations from the top of Emu Mountain, which dominates the Australian coast. The site effectively had a side view of the whales’ annual migration route to the Southern Ocean, where they feed extensively.
In 1997 he commanded the singing. Widespread fighting came later, during the 2000s, with ramming and charging maneuvers dangerous to both attacker and target, according to the study.
“Men must weigh the costs and benefits of each tactic,” Dunlop says in a press release.
Humpback Whale Song Patterns
While the males compete aggressively, they also share a communal song, as Australian populations tend to mimic a unified composition and are distinguished by how they diverge from it. This evolution continues until song patterns from outside populations filter in and trigger a “revolution” every few years, a drastic overhaul in which the whales ditch the old for the latest trend.
Read more: Understanding how whales communicate
Some humpback whales continue to sing as they swim alongside the females, in a sort of serenade, but a greater concentration of males has suppressed this practice, research has found.
“If the competition is fierce, the last thing the male wants to do is announce that there is a female in the area,” Dunlop says in a press release, “because it could attract other males who could outbid the singer for the female. .”