The findings are described in the 19 April issue of the journal Science. An international team of scientists studied the cave, led by the United States' Anna Roosevelt, curator of archaeology at Chicago's Field Museum and professor of anthropology at the University of Illinois in Chicago.
The site, Caverna da Pedra Pintada, is one of a series of Paleozoic sandstone caves first noted for their rock paintings by nineteenth-century European naturalists exploring the area around the town of Monte Alegre on the Amazon north bank, between Manaus and Belem. Brazilian archaeologists and speleologists had visited the cave but never excavated it. When Roosevelt began scouting the region for potential Paleoindian sites, Monte Alegre's secretary of culture, ecology teacher Nelsi Neif Sadek, brought Roosevelt to Caverna da Pedra Pintada.
"I could see right away that it was a good bet," says Roosevelt. "It looked very liveable -- light, airy and dry." Roosevelt brought in her team and they began to dig through well-preserved layers representing thousands of years of intermittent human occupation. Near the bottom, where Roosevelt hoped to find evidence of Paleoindian life, the soil "turned sterile and I thought, `Well, that's it. I wonder where else we can look in the area?' But we dug a little further and suddenly something snapped up into my face. It turned out to be a spear-point flake. Then the soil turned black." She had struck the archeological equivalent of gold: a layer of soil filled with dateable charcoal from human campfires and thousands of biological and cultural remains from a society that, until now, had not been thought to exist.
For decades, the general consensus has been that the earliest Americans, or Paleoindians, came from Asia across the Bering Straits near the end of the Ice Age and migrated down the Andean chain into South America, getting by as big-game hunters adapted to open, temperate regions. Despite some evidence suggesting the presence of early human foragers in subtropical areas east of the Andes, "the common assumption was that game and plant food were too scarce in the rainforest to support humans who hadn't yet developed slash and burn agriculture," says Roosevelt. But the new evidence shows that Paleoindian families lived in Caverna da Pedra Pintada for nearly 1,200 years, foraging food from the forest and river, crafting distinctive spear points and wood-working tools chipped from stone, and decorating rocks with red and yellow images, including ghostly handprints of adults as well as children. Their culture appears to have been very different from their contemporaries in the North, further challenging the traditional view, says Roosevelt, that the North American Clovis tradition was the "donor culture of early South American societies."
Other possible Paleoindian cultures found throughout eastern South America have not been widely accepted by archaeologists due to questions about their age and ecological adaptation. Roosevelt's team subjected a wide range of the newly recovered materials to various dating techniques in a number of different laboratories around the world, and the 69 resulting dates all fall close together -- between about 11,200 and 10,000 years ago.
"It seems Paleoindians were able to adapt to a broader range of habitats than has been thought," says Roosevelt. "Amazonia, far from a dead end, fostered a dynamic cultural trajectory over thousands of years."
The early foraging bands, she says, eventually gave way to fishing villages where pottery-making developed. Pottery fragments in Caverna da Pedra Pintada and nine other nearby sites date back between 5,000 and 7,500 years ago, making them the oldest pottery yet found in the Americas.
Roosevelt's team included three Brazilian researchers: Marcondes Lima da Costa of Federal University of Para, Cristiane Lopes Machado of Linhares Forest Reserve, and Maura Imazio da Silveira of the Goeldi Museum in Belem and of the University of Sao Paulo. In addition, Lazaro Ribeiro, whom Roosevelt calls "a forest savant from a small village near the cave," helped to identify most of the plant and animal species excavated from the layers. Ten taxonomists from the Goeldi Museum, the New York Botanical Garden, Michigan State University, and the Field Museum also worked on the identifications. Sites similar to Caverna da Pedra Pintada will help anthropologists rewrite the story of human evolution.
The conventional emphasis on cultures built around big-game hunting "has some serious implications" that can now be further challenged, says Roosevelt. "For example, sociobiologists have used our supposed descent from hunters to support a genetic basis for human behaviors like aggression and certain gender roles common in modern Western cultures, such as men bringing home the food and women tied to domestic chores." The prehistoric food-remains in the Brazilian cave, however, include not only large animals but also many very young animals -- a sign that women and children, as well as men, could have helped acquire food.