NEW YORK Researchers have discovered life-size rock carvings of camels , gazelles and other animals in the Saudi Arabian desert. The carvings date back to around 12,000 years ago and many are over 1.8 meters tall. Scientists say they were created using a wedge-shaped rock to create sharp lines. Several were etched on narrow ledges so the artists couldn't even step back to survey the final product as they were working. “To engrave that much detail with just a rock takes real skill,” said Maria