Saliva soup is delicacy

Answer: They're the latter, as described by Dr. Massimo Marcone in "In Bad Taste? The Adventures and Science Behind Food Delicacies."

Take kopi luwak, Indonesian for coffee and civet, from the island of Sumatra where the arboreal catlike palm civet consumes the sweet, ripe red coffee cherries with beans inside. After being "deposited," these are collected, washed and roasted, producing a chocolaty "cat-scat" coffee selling for more than $1,300 U.S. per kilo ($600/pound), "rarest and most expensive beverage anywhere."

Edible bird's nests derive from the Indonesian male swiftlet that builds its home in caves using strands of sticky saliva. After cleaning, the nests are air-dried and packaged for sale around the world. When cooked in water or chicken broth with rock sugar, the "saliva soup" at $80-$100 per bowl has a taste and texture like tapioca pudding.

Now for some casu frazigu (maggot cheese), head to Sardinia where it originated. As the sheep-milk cheese ages, fly larvae spread throughout, excreting digestive enzymes that give it its creamy texture. When Marcone first encountered the cheese, he was struck by "the clicking sound of thousands of tiny maggots hitting the container sides, audible from six meters (20 feet) away." Traditionally served as a spread on flatbread, it's popular at Italian weddings and other special occasions.

Question: Have you heard the one about how if you leave a fan running overnight with the door and windows shut, you can suffocate as the fan uses up the oxygen and produces lethal amounts of carbon dioxide? Dozens of people are said to have perished. This particular "urban legend" has circulated in South Korea; most South Koreans don't believe a word of it but still keep it alive, so what's the point?

Answer: Every culture has its share of word-of-mouth nonsense, says New Scientist magazine, but it actually has a deeper purpose: storytelling.

Urban legends, for all their implausibility, keep the listeners' attention. They entertain, thereby enhancing social relationships, note researchers at New Zealand's University of Waikata. "Lots of us love to have a rapt audience even if that means spouting garbage." So it's little wonder the yuckiest, grisliest tall tales are the ones that survive.