A new study of Australian humpback whales provides researchers with a disheartening discovery: their melancholy songs are on the decline. The graceful mammals have instead resorted to other methods of attracting mates: violence.

Their songs are an ever-evolving language allowing the animals to communicate with each other. The whale song is believed to have multiple purposes, but perhaps the most important purpose is to find a mate. This new discovery, however, suggests that this purpose is gradually declining. Instead of singing to one another, the whales have resorted to fighting and charging potential competitors.

Researchers believe that there is a very obvious cause of this change in behavior: whale populations and the history of whaling. The process of hunting whales to gather resources such as meat and blubber had a large impact on the population of whales in the 1960s. This process threatened the extinction of humpback whales, but most countries have made it illegal to participate in this practice, with few exceptions. This ban has allowed the humpback populations to grow, causing the animals to come into contact with one another more frequently. Therefore, rather than singing their romantic gestures, the males don’t risk the potential of alerting other males to their presence. 

“When there were fewer of them, there was a lot of singing—now that there are lots of them, no need to be singing so much,” Marine biologist Rebecca Dunlop said.

Scientists used hydrophone buoys to record whale songs and compared the data to the recordings of previous years. These buoys are set up alongside the whales’ migration route that led to Antarctica. Observers also took visual recordings of the whales to understand their behavior. The research reveals that widespread singing was prominently used in the late 1990s, and that the fighting began in the 2000s.

Some males continue to participate in the typical well-known song in order to attract females. However, the majority have abandoned the practice.