A prehistoric Spanish hunting group that may have even had its own gang symbols appears to have drawn, hunted, crashed in a cave, eaten, recycled waste and moved on, suggests a new study. The research hinged on one major clue — a buried pile of mysterious black bones found in a dark, dank room at the interior of El Mirón Cave near the northern coast of the Iberian Peninsula.
     This cave was like a residential hotel for traveling groups of Stone Age hunters, according to lead author Ana Belén Marín Arroyo, who worked with Lawrence Straus and other scientists. "It's a mountain settlement next to the coastal plain that would allow a seasonal residential mobility from the coast towards the interior at summer time, coinciding with the migrations of red deer herds to the high altitude grass," Arroyo said. Arroyo, a researcher in the Department of Geography, Prehistory and Archaeology at the Universidad del Pais Vasco in Spain, said engraved red deer shoulder blades, along with images of red deer hinds found at the site were probably 'stylistic markers of a regional band.' The cave is also well known for rock art and decorative objects, such as shell and tooth ornaments.
     The black bones, which date to around 13,000 years ago, intrigued Arroyo and her team, especially as different colored bones were excavated within other parts of the cave. The scientists first determined that the bones belonged to butchered red deer, ibex, roe deer, chamois (a European goat antelope) and small carnivores. The tests revealed the bones had not been painted or burned. Instead, the team determined black staining was due to the presence of manganese oxides and hydroxides. In an amazing bit of detective work, the scientists discovered that abandoned organic matter — basically leftover meat and other food waste — decomposed in the room with the bones.
     Based on the timing of this natural decomposition, along with clues provided by deer dental remains, the researchers believe the hunters killed mostly red deer in the spring and summer, during which time they stayed in the cave. They likely occupied the cave's large, well-lit outer vestibule, and used the interior room with the bones as a makeshift place for garbage.
     Geoffrey Clark, a professor in the Department of Anthropology at Arizona State University, said that he shares the team's conclusion about the black bones. He said, "The damp, dark conditions in the inner cave, combined with the rotting garbage, resulted in heavy manganese staining in what was probably a dump." Clark added that the study provides "a very consistent explanation for a complex phenomenon that sheds light on the human use of the cave."

Source: Discovery Channel (23 August 2007)