suggested that the development may be the result of “runaway selection.”
Early humpbacks with complex songs were so much more successful at mating that they gained a substantial evolutionary advantage over their brethren with simpler vocalizations. This led to some very large, sometimes very noisy animals.
Julien Bonnel, an associate scientist at the Woods Hole Oceanographic Institution in Massachusetts, said the growing research also shows the importance of collecting data over many years, offering insights not only into whales but ocean conditions that affect other species.
The technology for recording whales has gotten much cheaper over the last dozen years or so, making it more accessible to researchers. And computer programs that analyze huge data sets quickly have helped interpret years of these recordings.
Tagging whales without hurting them has produced more data, Noad noted, but the tags remain on the whale only for a few hours, limiting the information that can be collected.
In one of the new stud- ies, led by scientists at the New York-based Wildlife Conservation Society, researchers tracked humpbacks singing along the east and west coasts of Africa, comparing songs sung by those off the coast of Gabon to those near Madagascar.
The study, published in the journal Royal Society Open Science, confirmed that the two populations interact, noting overlap in their vocalizations.
The researchers recorded songs annually from
2001 to 2005 using hand-held hydrophones aboard boats.
“Male humpback whales within a population tend to sing the same song type, but it’s continuously changing and evolving over time,” said Melinda Rekdahl, the study’s first author and a marine conservation scientist with the wildlife society. “It’s thought to be one of the best examples of cultural evolution in the animal kingdom.”
Rekdahl wasn’t on the boat that collected the sound for her new study, but she knows firsthand that “it can be an amazing experience,” she said.
The sound of a nearby singer resonates through