Uncovering Secrets of Blue Whale's Song

John Pickrell
for National Geographic News
February 6, 2004

This story is one of a series looking at National Geographic Crittercam research. Crittercam is a research instrument worn by wild animals and equipped with a video camera and other information-gathering equipment. Crittercam is used on animals both in the ocean and on land.

To learn more about the Crittercam's field test in California, tune in to the Crittercam: Blue Whales episode on the National Geographic Channel in the United States on Friday, February 6 at 8 p.m. ET. Got a high-speed connection? Click here to watch previews of the Crittercam television documentaries on the National Geographic Channel Web site.

The haunting call of the blue whale is the most intense of any animal alive. These rhythmic pulses and deep moans are so loud they travel across entire oceans, yet the frequency of these calls is often so low that they are totally inaudible to human ears.

Though marine biologists are still at a loss to explain exactly what purpose blue whale calls serve, deciphering this lonely song could assist in conserving the endangered species. Despite being perhaps the largest animal ever to have lived on Earth, the blue whale's low numbers, elusive nature and tendency not to follow consistent migration paths make it difficult to study.

"One of the challenges in understanding the status of this species is knowing how many are out there," said National Geographic in-house marine biologist John Francis, based at Society headquarters in Washington D.C. Remotely listening to and measuring whale song, which travels for thousands of miles, is one off-beat option. "But first we need to know who is calling, how often and under what circumstances," he said.

Now, in an effort to glean new insights into calling and other behaviors, National Geographic Crittercam documentary makers have teamed up with Francis and whale expert John Calambokidis to capture both audio and video footage from blue whale-worn cameras for the first time. That unique footage, captured off the coasts of California and Mexico, has helped shed light on vocalizations, and provided novel insights into swimming dynamics and feeding behavior.

Brush with Extinction

Monitoring blue whales (Balaenoptera musculus) off the coast of California by taping vocalizations and other methods is an important task. These animals have barely rebounded from the brush with extinction dealt by whaling.

There may have been 300,000 blue whales at the end of the 19th century. Incredibly by 1966, when their hunting was banned by the International Whaling Commission, that number had dwindled to just a few thousand.

"Blue whales are so large and fast, that prior to the widespread use of explosive harpoons and modern ships [in the 20th century] whalers couldn't go after them," said Calambokidis, one of the world's foremost blue whale biologists with nonprofit institute Cascadia Research in Olympia, Washington.

Blue whales—each of which can measure 90 feet (27 meters) or more in length, weigh up to 150 tons (136,000 kilograms), and yield 120 barrels of oil—became the focus of the whaling industry in around 1900. That slaughter peaked in 1931 when 29,000 blue whales were killed in one season. "Forty years ago there was uncertainty as to whether the blue whale was doomed to extinction, because populations had been reduced so dramatically," said Calambokidis. Recovery has been slow, and 10,000 to 12,000 blue whales are estimated to survive today.

One of the least threatened populations (numbering up to 3,000 whales) spends the summer off the coast of California, and it is to these animals that Calambokidis has turned his attention.

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