Humpback whale

       Humpback whales are increasingly giving up singing , When a male humpback whale sings, he hangs his 40-foot-long, 40-ton body upside down in the water and makes some of the most distinctive sounds in the world. According to a 2018 survey who analyzed the songs of Australian humpback whales, the whales share an ever-evolving language, like a local dialect, made up of “phrases” joined together to form “themes” which are then arranged to make songs. The squeaks and moans become more elaborate as the hunchbacks add their own embellishments, much like a folk singer changing a chorus.

Although the humpback song is believed to serve several purposes, perhaps one of the most important is to attract a mate, this majestic ritual may be in decline. A a new study of Australian humpbacks has found that the massive mammals now often resort to fighting for love, attacking and hitting other potential suitors, among other tactics. Such fights usually occur after the male has approached a female and swims to her side, and others swoop in to take his place, as documented in a writer’s account of whales fighting whales.

Whaling and behavioral changes /Humpback whales are increasingly

Researchers say the increase in courtship violence has a simple explanation: changes in humpback 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 humpbacks, leaving only about 200 by 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 win mates through non-singing means, including head slaps, the study found. While the song attracted women, it also warned men who sometimes tried to assert their dominance.

“Humans are not the only ones undergoing major social changes when it comes to marriage rituals,” said lead researcher, Associate Professor Rebecca Dunlop of the University of Queensland, in press release.

The study provided 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 determine whale song, and combined this data with visual observations from the top of Mount Emu, which overlooks the coast of Australia. The site actually had a side view of the whales’ annual migration route to the Antarctic Ocean, where they feed intensively.

In 1997, singing ruled. Widespread fighting came later in the 2000s, with ram and charge maneuvers dangerous to both the attacker and the attacked, according to the study.

“Men must weigh the costs and benefits of each tactic,” Dunlop said in a press release.

Humpback whale song patterns /Humpback whales are increasingly

While males compete aggressively, they also engage in communal song, as Australian populations tend to mimic a single composition and differ in how they deviate from it. This evolution continues until song patterns from outside populations are filtered out and caused a “revolution” every few years a drastic overhaul where whales ditch the old for the latest trend.

Read more: Understanding how whales communicate

Some humpbacks continue to sing as they swim with the females, in a sort of serenade, but higher concentrations of males suppressed the practice, a study found.

“If competition is fierce, the last thing a male wants to do is advertise that there’s a female in the area,” Dunlop said in a press release, “because that could attract other males who might outcompete the singer for the female.”

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