for National Geographic News
The giant rock art murals that grace the walls of hundreds of shelters and caves found in the hardscrabble hills of the high sierra in Baja California Sur, Mexico, date back as far as 7,500 years ago, according to data from an ongoing study of the area.
The ancient dates for the paintings cast little light on the mystery of who made them and why, but it suggests that whoever the painters were they came well before the Aztecs established their culture in central Mexico in the 12th century A.D.
"Once we did the dating and got to know how old they are, we were surprised by their antiquity because they look so fresh, so well preserved," said Alan Watchman, a geoscientist and Australian Research Fellow at the Australian National University in Canberra and co-leader of the study team.
The paintings are of giant humans and animals, mostly done in red and black but also in white and yellow. The human figures are static, but the animals bound in herd-like movement across the rock-wall canvases.
Harry Crosby, an author and Baja California rock art expert in La Jolla, California, suggests that the paintings might represent a sense of "us and them" with the humans painted to depict how they dealt with each other in a static manner but with the animals as "food on the hoof."
"The vision would be of the animals getting out of there and when [the painters] picture them one could argue they are trying to set up a kind of hunting magic," he said, but added that it is difficult to know what they were thinking if we don't even know who they were.
The murals had previously never been dated and even today little is known about the people who created them or what they were meant to communicate. Watchman and his colleagues are conducting a multi-year project to put the paintings in cultural context.
The team, which is partially funded by the National Geographic Society's Committee for Research and Exploration, is working in the Sierra de Guadalupe. The murals are found in shelters that hang within spectacularly steep and pristine canyons.
Before the team started work in 2001, about 90 rock art sites were known in the Sierra de Guadalupe. Since then, the team has documented more than 320 additional sites. Hundreds more sites are known from the Sierra de San Francisco, which lies to the north.
Now that preliminary dates for the paintings are established, the team is searching for a site they can excavate for other materials to substantiate the dates of the art and help tell the story of who the painters were, how they used the landscape, and how they traveled.
"We are trying to put all that information together, but it is an arduous task," said Watchman, who is collaborating with Lucero Gutierrez, an archaeologist with Mexico's National Institute of Anthropology and History and Marisabel Hernandez Llosas, an archaeologist with the National Council of Science and Technology of Argentina.
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