Pottery finds suggests oldest cooking CAMBRIDGE, Mass., June 29 (UPI) -- Pottery fragments found in a cave in China suggest an ice age, not the development of agriculture, pushed human ancestors to start cooking, researchers say. Researchers from Harvard University said the shards, parts of the oldest pots in the world, have been dated to 19,000-20,000 years ago, around the time of the Last Glacial Maximum, NewScientist.com reported. That puts the pots thousands of years before people began farming some 12,000 years ago, suggesting the pots were made by hunter-gatherers, contrary to previous thinking. "The making of pottery is not necessarily related to agriculture," Harvard researcher Ofer Bar-Yosef said. Rather, he said, extreme cold could have pushed Chinese hunter-gatherers to start cooking food 20,000 years ago, since cooked food yields more energy than raw food and could have helped people survive. It takes some form of stress to push species to undergo such major changes, Bar-Yosef said. The shards found in Xianrendong cave in southeastern China are the remains of crude pots and bowls probably about 8 inches across, he said. "They were poorly fired and easily breakable," he said, and their outer surfaces carry scorch marks and small amounts of soot, suggesting they were used for cooking.