SAN FRANCISCO - Blue whales are up to something - but exactly what isn't clear.
A new study published in the latest edition of the Journal of the Acoustical Society of America reports on the findings of Roger Bland, a professor of physics and astronomy at San Francisco State University, and his colleagues, who spent from September to November 2001 collecting more than 4,300 recordings of blue whales singing about 50 miles offshore of Half Moon Bay.
The recordings were taken about 1,000 meters below the surface of the ocean, Bland said. While analyzing the recordings, the researchers discovered that blue whales are able to fine-tune the pitch of their call, while achieving perfect synchronization of 16 hertz (cycles per
Play whale sounds
"The study shows that somehow they've decided someone has set up the 16 hertz and the whales have decided to tune their calls to it ... There's some sort of social activity going on that's fairly sophisticated," Bland said.
He expressed surprise at the findings, which were analyzed several years ago but were just now published. When the study first began, he explained, the team had hoped to find differences in pitch that would provide some insight as to how the whales live and their social structure. The actual results, he said, are "very peculiar."
He speculated that since the blue whale song is produced only by males, perhaps females tune in to try and find a mate. They could do this by using a combination of the rising and falling pitches in the songs themselves, as well as the Doppler shift, or the change in pitch heard when the source of the sound is moving toward or away from an individual, similar to how a police car with its sirens on sounds as it passes by.
The only thing the researchers have been able to determine is that the whales' singing is coalescing into a single frequency of 16 hertz, "like a choir singing together where they all mutually tune in to the same frequency."
Whatever conclusions researchers draw from that phenomena are pretty speculative, he added, but "the fact that they're all tuning to the same frequency is pretty remarkable."
The study may prove useful in future studies, including why blue whales' overall population has remained low while other species have continued to rise, and why their pitch has been decreasing in recent decades. He said that noise from ships and boats is in approximately the same frequency range as whales' songs, so that may be causing them to lower their pitch.
Blue Whale study
Blue whales are able to synchronize their songs at 16 hertz
The study was conducted September-November 2001
Researchers at San Francisco State University collected a sampling of 4,378 blue whale songs
To listen to a blue whale song, go to www.santacruzsentinel.com