Sperm whales eject an intestinal slurry called ambergris into the ocean, where the substance hardens as it bobs along. Eventually it gets collected along shores—most often as sheer happenstance, as in the case of eight-year-old Charlie Naysmith in the U.K. a few days ago.
Walking along the beach in Dorset with his dad, the boy found what looked to be a very odd rock. He and his dad used Google to help identify it as ambergris. Weighing more than a pound, it is said to be worth up to U.S. $63,000.
The value of ambergris lies in its role in the fragrance industry. High-end perfumes from houses such as Chanel and Lanvin take advantage of the ability of ambergris to fix scent to human skin.
The smell of ambergris itself varies from piece to piece, ranging from earthy to musky to sweet. If a perfume house's "nose"—the person responsible for choosing scents—likes the aroma, the ambergris can be worth thousands an ounce.
Though it is illegal to use ambergris in perfumes in the U.S. because of the sperm whale's endangered status, foreign markets, especially French, remain strong. (Learn secrets of whale evolution in National Geographic magazine.)
Scientists still don't know for sure the exact origins of ambergris. They do know that when sperm whales have a stomach or throat irritant, often a squid beak, they cover it in a greasy substance and cast it out.
(Rare Pictures: Giant Squid Eaten by Sperm Whale.)
It was once thought the ambergris was ejected by mouth. As of now, the argument seems to be weighted toward the back end of the whale.
Johnna Rizzo is a Departments editor for National Geographic magazine and the author of the nonfiction children's book Oceans. More of her writing on ambergris will appear in the magazine's October issue.