Elders of the deep

Biologists, long stumped at figuring out how old whales are, lucked out when a 50-ton bowhead caught off Alaska came with a telltale clue: fragments of a harpoon lodged in a shoulder bone.

The weapon was used more than a century ago by whalers from New Bedford, enabling researchers to estimate that the whale was at least 115 years old and providing more evidence for their long-held belief that the bowhead whale is one of the longest living mammals on earth, surviving for up to 150 years.

I'd initially spotted this story elsewhere, but this Boston Globe article answers, at least partially, the question of the projectile's datability:

Anthropologists have analyzed hunting devices found in whales before, said Scott Kraus, vice president for research at the New England Aquarium in Boston.

It was often difficult, however, to determine when the weapon was fired.

"What you don't know is if some Yankee whaler had a harpoon made in 1830, traded it to an Inuit, and the Inuit or his offspring used it 40 years later," Kraus said.

But because the bomb lance was patented and stocks were used up quickly, Bockstoce and his colleagues identified a narrow window in which they believe the whale was shot, sometime between 1885 and 1895.

A number of other articles made a big deal of the patent date on the lance head, apparently without appreciating that such a mark provides only a terminus post quem, absent further information. A widespread misconception -- look on eBay, and you'll see how many sellers think that something marked with an 1884 patent date must date to 1884 -- but one should expect better from our journalistic establishment.

In any event, the story is a poignant reminder of what is lost when a whale is killed. It may not be widely appreciated among the general public how long-lived (and, correspondingly, slow-to-reproduce) the great cetaceans are. This 2000 article helps fill out the picture:

Next time you hop a whale-watching tour or gaze out across the ocean from the coast's edge, consider this: Some of the whales out there now may have been swimming around during the Civil War. Or even when Thomas Jefferson was president.

In studies that could rewrite biology textbooks and establish whales as the longest-living mammals on Earth, scientists in Alaska and at the Scripps Institution of Oceanography in La Jolla have estimated the ages of three bowhead whales killed by Inupiat Eskimos in northern Alaska at 135 to 172 years. At the time it was killed, a fourth bowhead whale was believed to be a stunning 211 years old, the researchers concluded.

The ages were determined by studying changes in amino acids in the lenses of the whales' eyes.

Yet adding a layer of corroboration -- and a dash of Hollywood intrigue -- Inupiat hunters in Barrow and other villages along the frozen north coast of Alaska have found six ancient harpoon points lodged in the thick blubber of freshly killed bowhead whales since 1981. The harpoon points are made of ivory and stone, two materials not used by native Alaskan whalers since the 1880s, when they were introduced to steel harpoons. . .

Other whales across the globe also may be much older than previously thought.

There's also a quite detailed press release here from the New Bedford Whaling Museum.

Posted by David on June 19, 2007 3:12 PM