Male humpback whale acoustic behavior

Male humpback whales sing, and their song is one of the most conspicuous underwater acoustic displays in the animal kingdom. Surprisingly, and despite the large number of studies undertaken, the function of humpback whale song is still argued. Research in the Australian migratory corridor found that males adopted a conditional mating strategy. When the number of nearby males was low, males sang. As male density increased, males switched to non-singing tactics. Over time, as the population increased post-whaling, a higher proportion of males sang in the early years, with a higher proportion using non-singing tactics in later years. Singing is a loud broadcast acoustic display and likely contains fitness information. This information is available to females and other males within acoustic range. Males join females whilst singing, but if they sing in the presence of other males, are at risk of attracting competition. The alternative tactic is to actively, but more quietly, seek out females. By not singing, they are not broadcasting their fitness to other males and therefore reducing the risk of attracting competition. Since males are adapting their behavior based the presence of females and other males, song likely acts as a fitness indicator to both sexes.