Australasian Science: Australia's authority on science since 1938

The Top 40 of Whale Songs

By Magdeline Lum

A playlist of whale songs takes 2 years to reach French Polynesia.

Scientists have known for decades that whale songs evolve over time. Researchers at The University of Queensland (UQ) have found that the songs of male humpback whales change every year as they migrate across the Pacific Ocean. Previous research has revealed that only male humpback whales sing, and that song is a behaviour used in courtship and mating.

The researchers identified 11 different humpback whale song types in an 11-year period among six neighbouring populations in the Pacific Ocean. They found that it took around 2 years for new whale songs originating in Australia to reach French Polynesia. “I noticed that the songs moved quite rapidly through the six populations, usually taking 2 years to spread all the way across the region,” says PhD student Ellen Garland.

The movement of this change in the whale song playlist occurred in a step-wise fashion, similar to the game of Chinese Whispers. However, unlike in humans, there were few differences between the original and final songs. The spreading of songs could be due to males hearing each other’s songs along shared migration routes or by males moving out to another group for breeding.

“The reason we believe the song tends to travel east is because the eastern Australian population is the largest in the region and has a greater influence than the smaller Oceania ones,” Garland said.

The researchers found that all the male humpback whales of a population sang similar songs that were continually changing or evolving over time. “Song can undergo evolutionary change, which occurs over a long period of time, or revolutionary change, where the males start singing a completely new song,” she said.

The trigger for a song change is unknown at this stage but researchers have likened it to how people follow fashion trends. “Someone starts a new trend and, before you know it, everyone starts wearing the same thing. As long as something is new and novel it seems to be incorporated fairly quickly. We don’t know who are initiating these changes but we do know that there are changes happening,” Garland says.

The study is the first documentation of a repeated, dynamic cultural change occurring across multiple humpback whale populations across a large geographical scale. It was undertaken in collaboration with the South Pacific Whale Research Consortium and investigated song similarity over an 11-year period within the South Pacific region focusing on the populations of eastern Australia, New Caledonia, Tonga, American Samoa, the Cook Islands and French Polynesia.

If you want to know how attractive a man is, researchers suggest that you look down – at his hands. Researchers have linked the ratio between the length of his right index finger and ring finger to facial attractiveness. This ratio is termed “2D:4D”, and the researchers say that it is driven by the sex hormone testosterone.

The amount of testosterone that a foetus is exposed to at the end of the first trimester determines this 2D:4D ratio. Greater testosterone levels in utero are associated with a higher 2D:4D ratio and higher-quality sperm produced by the male.

Exposure to this pre-birth testosterone is also thought to have an impact on looks. This is different from other sexual and masculine traits, such as voice frequency and body odour, as levels of adult testosterone regulate these.

British, French and Swiss researchers photographed 49 caucasian males between 18 and 33 years of age and measured the length of their ring and index fingers. They also recorded their voices and took swabs collecting their odour.

A group of 49 caucasian female students of the University of Liverpool between 19 and 34 years of age then rated the attractiveness of the men based on the photographs, voices and odour.

Men whose ring fingers were longer than their index fingers were more likely to considered attractive by women. When it came to scoring these men in terms of voice and odour, they were not rated any more highly than other men.

During adulthood, testosterone determines characteristics like voice and odour and the levels of testosterone changes over the course of a day and in different situations.

The research has been published in the journal Proceedings of the Royal Society B: Biology Letters.