Whales who are better singers are more successful at mating

By Stephen Beech

Older male whales are more successful at mating than their younger rivals because they are better singers, suggests a new study.
 
Older singing male whales are increasingly successful at siring offspring compared to younger males, reveals the research.

The findings suggest that male humpback whales may need time to learn and refine their singing and competitive tactics - giving experienced males a clear advantage, say scientists.

Researchers believe that as the whale population recovers after centuries of being hunted, females may also become more selective - which could lead to greater success among males with favourable traits or the strongest performance. 

The international study, led by the Sea Mammal Research Unit at the University of St Andrews in Scotland, showed that the role of age in male humpback whale reproduction has changed as their numbers grow.  

Whaling drove many species to the brink of extinction, but scientists say its legacy runs deeper than just a drastic decline in numbers. 

Decades after commercial whaling ended, researchers found its impacts continue to shape whale populations - influencing not just how many whales there are, but which males get to reproduce.  

The study, published in the journal Current Biology, assessed almost two decades of data from humpback whales breeding in New Caledonia in the South Pacific.

Drawing on long-term monitoring conducted by the NGO Opération Cétacés, the research team analysed examined changes in age structure, behavior, and paternity in male whales. 

They found that during the early years of recovery, the population was dominated by young males.

Over time, as overall numbers increased, the age structure shifted to a more even age distribution amongst older and younger males.

Crucially, as older individuals became more common, they became increasingly successful at siring offspring compared to younger males. 

Humpback whales have never been observed mating in the wild, meaning that who fathers a calf remained largely unknown until now. 

The research team applied genetic analysis to identify paternity and used an "epigenetic molecular clock" to estimate the age of individual whales; all from just a small piece of whale skin. 

Male humpback whales are famous for producing some of the most elaborate songs in the animal kingdom.

Their powerful vocal displays can often be heard far across breeding grounds and are thought to play a role in mating. 

Males may also escort females or engage in intense physical competition with rival males. 

Study senior author Dr. Ellen Garland ,of the Sea Mammal Research Unit, said: “Mating behavior, and who was successful at mating, changed with these shifts in age structure.

"As the population recovered, there were more older males than expected singing, escorting females, and successfully fathering calves compared to younger animals”. 

She says the study highlights the importance of ongoing research on recovering populations to understand how the consequences of exploitation shape population dynamics and reproduction over time.

Study lead author Dr. Franca Eichenberger, also from the Sea Mammal Research Unit, said: “It is only now, as whale populations recover and new analytical tools become available, that we are beginning to understand how far-reaching the consequences of whaling truly are. 

"The impacts extend beyond population size - they shape behavior, competition, and reproduction. 

"Virtually all populations of whales have changed due to whaling; our work shows that they continue to change as they recover.

"This is why the continued long-term monitoring of previously exploited whale populations is so important."

She added: "Humpback whales have shown a remarkable comeback over recent years.

"Now is the time we can learn so much more about their behavior and life history.