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BOB HIRSHON (host):
Elephant CSI. I’m Bob Hirshon and this is Science Update.
Most elephant ivory seized by customs officials comes from elephants killed recently, and not from older ivory stockpiles. That means more elephants are being killed each year than was thought. This according to University of Utah researcher Thure Cerling and his colleagues. In the Proceedings of the National Academy of Sciences they report using radioactive isotope analysis of seized ivory.
THURE CERLING (University of Utah):
We sampled the ivory that had been formed by the animal just before it died, the last two or three months of its life. So that’s the ivory right inside the pulp cavity.
He explains that every living thing absorbs radioactive carbon 14 from the air. Since it degrades at a fixed rate, the isotope acts like a time stamp in the tusks, revealing when the animal was born and when it died. The work is helping officials understand the dynamics of the illegal ivory trade. I’m Bob Hirshon, for AAAS, the science society.
Story by Bob Hirshon