On the trunk of a gnarled, centuries-old oak tree, about 90 miles southwest of Phoenix, Arizona (USA), are odd carvings of six-legged, lizard-like beings. The tree is located at Painted Rock, an archaeological site peppered with hundreds of ancient petroglyphs, images created upon rock surfaces. Known as the 'scorpion tree,' locals had long believed that cowboys were behind the tree carving (the technical term is 'arborglyph'). But paleontologist Rex Saint Onge knew it dated to long before then. His analysis offers a glimpse not only into the cultural history of the Chumash people, the Native American tribe that once inhabited the region; it also provides unique insights into their scientific expertise.
     Although Saint Onge is uncertain how old the tree carving is, he believes that nearby Chumash residents may have maintained it until the early 20th century. The arborglyph led Saint Onge to connect the symbols within the carving with the stars in the sky. After spending more time at the site, Saint Onge realized that the carved crown and its relation to one of the spheres was strikingly similar to the way the constellation Ursa Major related to the position of Polaris, the North Star. He quickly learned that the constellation could be used to tell the seasons and that the Chumash people also revered this astronomical relationship in their language and cosmology.
     It became increasingly obvious to Saint Onge that the arborglyph and related cave paintings weren't just the work of wild-eyed, drug-induced shamans - which has been a leading theory for decades - but that the ancient images were deliberate studies of the stars and served as integral components of the Chumash people's annual calendar. "This gives us an insight into what the indigenous people of Central California were doing," says Saint Onge, who published his theory last fall in the Journal of California and Great Basin Anthropology. "It wasn't just the daily simpleton tasks of hunter-gatherers. They were actually monitoring the stars."
     Saint Onge isn't the first to speculate that Chumash paintings might have astronomical implications. The anthropologist Travis Hudson did so back in the 1970s combining his observations of rock art with the cultural data recorded nearly a century earlier by ethnographer John P. Harrington. But when others went into the field to check out Hudson's claims, "much of it was pretty unconvincing," explains anthropologist John Johnson of the Santa Barbara Museum of Natural History. "That's what caused people to get skeptical about archaeoastronomical connections."
     That reluctance ruled for three decades until Saint Onge presented his findings to Johnson, and he was so impressed that he co-authored the journal article and is now quite open to the idea that the rock art he's studied might have something to say about the stars. "Whether we're right or not, I don't know, but we keep finding things that strengthen the idea," says Johnson. "And if we keep finding ethnographic support for it, I feel we're on safer ground."

Sources: Time (9 february 2010), Discovery News (10 February 2010)