PRATIE PLACE

Thursday, March 15, 2007

Bowhead whales live more than 200 years?

Extracts from
The old men of the sea
Whales Longevity

by Paul Rogers for the San Jose Mercury News, December 19 2000

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.

In other words, the whales apparently had been swimming around for more than 100 years after surviving earlier hunts by the Inupiats' great-grandparents.

At least two other scientists are now beginning different experiments to determine the whales' ages.

If it turns out that bowhead whales -- which live in the Beaufort and Bering seas between Russia and Alaska -- can indeed survive to be 150 years old or more, they would be the oldest mammals on the planet.

Elephants and some parrot species have lived to 70 in captivity. Tortoises can live to 100. Some fish, such as orange roughy and Chilean sea bass, are believed to live past 100. The oldest authenticated age to which any human has lived is 122 years. Jeanne Louise Calment, a French woman who met Vincent Van Gogh as a teenager, died at a nursing home in Arles in southern France in 1997.

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

"These are such poorly studied species, in terms of their age, behavior and everything,'' said Bada. ``I think this is just the tip of the iceberg, if you want to know the truth."

Despite bans on commercial whale hunting in the United States since 1946, the Inupiat are allowed to kill about 50 bowheads every year as part of special subsistence rights granted by the International Whaling Commission and the U.S. government. About 8,300 bowheads exist in the wild.

[Picture: a bowhead skull.]

For decades in Barrow, a remote town of 5,000 people with no access by highway, Inupiat elders have spoken of whales that several generations of hunters had seen and recognized, based on markings.

Anthropologists have since compared the stone harpoon points to others from the 18th and 19th centuries at the Smithsonian Institution in Washington, D.C.

About five years ago, George learned of work being done by Bada to date animals by their eyes. George, who had access to the frozen remains of bowhead whales killed between 1978 and 1997, mailed Bada the lenses from the eyes of 48 bowheads. Each eye is about the size of a billiard ball.

Through a technique known as racemization, Bada measured levels of amino acids, called aspartic acids, in the eyes, noting changes that can determine age. The technique has been used successfully on other whale and porpoise species and is sometimes used on humans by forensic pathologists.

More studies under way

Working with Judy Zeh, a statistician at the University of Washington in Seattle, they published their findings last year in the Canadian Journal of Zoology. In recent months, news of the discovery has been published in more widely read science magazines, such as Science News and New Scientist.

The researchers note that the estimates have a range of accuracy of about 16 percent. In other words, their estimate of 135 years for one of the older bowheads could be off by 23 years, ranging from 112 years to 158 years.

Another scientist, Mark Baskaran of Wayne State University in Detroit, is beginning experiments to estimate whale ages by measuring the decay of radioactive lead samples in bowhead bones. Researcher Cheryl Rosa of the University of Alaska plans to study the whales' skin, sampling pentosidine, a chemical that builds up with age and can be taken with small darts that do not injure the bowheads.

Why might bowheads live so long?

One theory is that because they live in harsh conditions, with fluctuating weather and food, the whales have evolved to live a long time and breed over many years so their species can survive.

Some experts say that if the phenomenal ages are borne out by future research, humans may have more reverence for whales, in the same way that redwood trees are valued for their ancient ages.

Contact Paul Rogers at progers@sjmercury.com

1 Comments:

At 6:27 AM, Blogger mark said...

I performed the histological marker assay on skin collagen for Cheryl Rosa. We did not find expected age-related increases in Pentosidine. It would have been nice to assay for this marker of carbohydrate metabolism in the lens, but the indigenous people like to keep that part, I am told.

-Mark Obrenovich

 

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