MEXICO CITY -- Experts say the number of mammoth skeletons recovered at an airport construction site north of Mexico City has risen to at least 200, with a large number of pits still to be excavated at what may be the largest mammoths graveyard in the world.
Archaeologists hope the site that has become "mammoth central" -- the shores of an ancient lakebed that both attracted and trapped mammoths in its marshy soil -- may help solve the riddle of their extinction.
Experts said Thursday finds are still being made, including signs humans may have made tools from the bones of the lumbering animals that died around 10,000 to 20,000 years ago.
