Wooing Whales

A mysterious sound in the ocean turns out to be the mating call of a whale.

Like an opera house, the seas resonate with the songs of creatures big and small. Scientists have long linked the most powerful of the ocean's arias to fin and blue whales-these giants are widely dispersed in all oceans and need to communicate over long distances. But until now no one knew exactly what-juvenile or adult, male or female-was belting out these guttural, far-ranging refrains or why. Turns out, male fin whales are the booming baritones of the oceans, and their songs are their calls for mates.

Academy research associate Alejandro Acevedo and colleagues tracked vocalizing fin whales in the Gulf of California, Mexico, by towing 120-meter-long arrays of hydrophones and sound-localization equipment behind a research vessel. After pinpointing a singing individual, they obtained a biopsy to genetically determine the whale's sex. In the study area, which had a 1:1 male-to-female sex ratio, only males made the characteristic low-frequency sounds.

The authors suggest in a recent issue of Nature that male fin whales make these long-distance calls to attract receptive females to areas where food is abundant. A similar explanation is suggested for blue whales, which make similar sounds. The finding may help evaluate whether shipping traffic, low-frequency military sonar, ocean acoustic research, and other human-made noises have an impact on whale populations.

Alejandro Acevedo, center, with Mexican colleagues David Maldonado (left) and Juan Carlos Salinas (right) during the study in Loreto Bay, Baja, Gulf of California, Mexico. Photo credit: Paloma Ladron