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 Researchers on Tuesday said they conducted an intensive study of
the vocalizations -- singing -- of a population of roughly 300
bowhead whales in the sea east of Greenland from 2010 to 2014,
using underwater microphones.
They amassed the largest collection of recordings ever made for
bowheads, revealing a diverse and constantly changing vocal
repertoire. The researchers, who identified 184 distinct songs,
said the singing apparently is a reproductive display by males.
Bowhead whales, hunted almost into oblivion centuries ago, can
exceed 60 feet (18 meters) in length. They are the only baleen
whale living year-round in the Arctic and have the thickest
blubber of any whale.
Among the world's whales, only bowheads and humpbacks produce
really variable songs. Other filter-feeding baleen whales like
blue, fin and minke whales produce much simpler songs that are
more or less the same every year.
University of Washington oceanographer Kate Stafford said
humpback songs are very orderly, akin to classical music, while
bowhead songs seem freer, akin to jazz music, not appearing to
follow a clear set of rules.
"They are highly varied. Some sound absolutely haunting," said
marine biologist Kit Kovacs of the Norwegian Polar Institute and
the University Centre in Svalbard. "But others sound as though
something wild is taking place in a barn."
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Whales use sound it to navigate, communicate and find prey and
mates. Sound travels efficiently underwater and much further than
light, and odors also do not transmit very well underwater.
"Whales sing to communicate 'intention,' in this case readiness to
mate. The song is usually only performed by males to communicate
both with other males -- 'I am bigger, stronger more motivated, et
cetera' -- and to females -- 'I am big, strong and highly
motivated,'" Kovacs added.
The research, published in the journal Biology Letters, confirmed
that the bowheads sang regularly from late fall to early spring.
"So songs are completely changing both within and between years. And
we don't really know why," Stafford said. "It's likely to remain a
mystery because they sing in the Arctic under heavy ice during the
polar night, conditions that are not very conducive to humans
getting out and seeing and studying them at this time of year."
(Reporting by Will Dunham; Editing by Sandra Maler)
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