MEXICO CITY, MEXICO—According to an Associated Press report, additional mammoth skeletons have been unearthed at an airport construction site north of Mexico City, bringing the total number to at least 200, in addition to the remains of about 25 camels and five horses. The animals are thought to have died trapped in the marshy soil of an ancient lake bed between 10,000 and 20,000 years ago. Humans may have driven the animals into the mud, or traveled to the site to scavenge the carcasses for food and materials for tools and weapons. Archaeologist Rubén Manzanilla López of Mexico’s National Institute of Anthropology and History said researchers are continuing to look for butchery marks and signs of tool use on the bones. To read about mammoth traps recently unearthed north of Mexico City, go to "Around the World: Mexico."