April 4 (UPI) -- Like Miles Davis, the bowhead whale has a knack for improvisation. A new survey of bowhead whale vocalizations suggests the marine mammal has a surprisingly large and varied catalogue of songs.
Compared to the songs of other whales, the bowhead's vocalizations are less standardized and more spontaneous.
"If humpback whale song is like classical music, bowheads are jazz," researcher Kate Stafford, an oceanographer at the University of Washington, said in a news release. "The sound is more freeform. And when we looked through four winters of acoustic data, not only were there never any song types repeated between years, but each season had a new set of songs."
Stafford first began recording bowhead whale singing in the Greenland Sea in 2008. In 2012, she and her researcher partners recorded the never-ending songs of bowheads during winter breeding season, evidence of a healthy population living off the coast of Spitsbergen, the largest island in Norway's Svalbard archipelago.
The latest research builds on the 2012 survey, offering further evidence of the bowhead's dynamic song craft. Stafford and her colleagues published their newest analysis this week in the journal Biology Letters.
The songs of humpback whales, which frequent breeding grounds between Hawaii and Mexico, are well documented. Humpbacks produce melodious songs with melodies unique to each population. The songs vary slightly from season to season.
"It was thought that bowhead whales did the same thing, based on limited data from springtime," Stafford said. "But those 2008 recordings were the first hint, and now this data confirms that bowhead whale songs are completely different from the humpbacks."
For marine mammals like whales and dolphins, sound is everything.
"Marine mammals live in a three-dimensional habitat where sound and acoustic information is how they navigate, how they find food, how they communicate," Stafford said.
The new research is only the beginning. The recordings present several new mysteries to be investigated. Scientists don't yet know why bowheads change their songs so frequently, and whether males and females participate equally in the melody-making.
Followup studies combining radio tag tracking with hydrophone recording could offer clues as to why the bowheads became the jazz musicians of the sea.
"Bowheads are superlative animals: they can live 200 years, they've got the thickest blubber of any whale, the longest baleen, they can break through ice," Stafford said. "And you think: They've evolved to do all these amazing things. I don't know why they do this remarkable singing, but there must be a reason."