30,000 year old Brazilian artifacts throw wrench in theory humans first arrived in Americas 12,000 years ago

It's no secret humans have been having sex for millennia -- but recently discovered cave art suggests they were doing it in the Americas much earlier than many archeologists believed.

A new exhibit in Brazil showcases artifacts dating as far back as 30,000 years ago -- throwing a wrench in the commonly held theory humans first crossed to the Americas from Asia a mere 12,000 years ago.

The 100 items on display in Brasilia, including cave paintings and ceramic art, depict animals, ceremonies, hunting expeditions -- and even scenes from the sex lives of this ancient group of early Americans.

The artifacts come from the Serra da Capivara national park in Brazil's northeastern Piaui state, on the border of the Amazon and Atlantic Forests, which attracted the hunter-gatherer civilization that left behind this hoard of local art.

Since the 1970s, Franco-Brazilian archaeologist Niede Guidon has headed a mission to carry out large-scale excavation of Piaui's interior.

"It's difficult to think there exists a site anywhere with a higher concentration of cave art," the 80-year-old Guidon told AFP.

Many paths led to Americas

Other traces of the civilization include charcoal remains of structured fires, explained Guidon, who hails from Sao Paulo.

"To date, these are the oldest traces" of human existence in the Americas, she emphasized.

The widely held theory has suggested human beings only reached the Americas some 12,000 years ago from Asia, crossing the Bering Strait to reach Alaska.

Some archeologists contend flaked pebbles at the Brazilian sites are not evidence of a crude, human-made fire hearth made some 40 millennia ago, but are rather geofacts -- a natural stone formation, not a man-made one.

But Guidon said she believes the Serra dwellers may have come originally from Africa, and she said the cave art provides compelling evidence of early human activity.

The paintings are estimated to date back some 29,000 years, she said, noting: "When it began in Europe and Africa, it did here too."

Other sites, including Valsequillo in Mexico and Monte Verde in Chile, also indicate the presence of communities tens of thousands of years ago.

These sites have led archeologists to speculate that peoples traveled various routes to reach the Americas and at different stages, archeologist Gisele Daltrini Felice told AFP.

In search of tourists

UNESCO conferred World Heritage status on the Serra da Capivara in 1991, but tourists remain thin on the ground, which frustrates Guidon.

"After putting in a great amount of effort (to promote the site) we are up to 20,000 visitors a year," the archeologist said.

But "World Heritage sites get millions, and we are prepared to receive millions," she added.

The interior of the Piaui region is marked by widespread poverty, which has much to gain from tourism, Guidon stressed.

But resources are lacking to promote the attractions in a remote corner of the giant nation, she said. The nearest city is the modest town of Sao Raimundo Nonato, which has spent years trying to have an airport built.

The EU is promoting both the new exhibit as well as a swath of conferences on the area under the auspices of UNESCO, Brazil's Institute of Parks and the country's Institute of Historic and Artistic Heritage.

"The idea is to promote cultural, historic and nature-based tourism in order to aid the development of areas adjoining Brazil's major parks -- and especially the Serra da Capivara, which has the most modern infrastructure," with 172 sites to visit, said Jerome Poussielgue, European Union cooperation and development officer for Brazil.

And the foundation behind research into the park is backing development projects -- including a ceramics factory that reproduces images of the cave art, a program aimed at giving local women work experience.

"We would like to help in the development of a region where women suffer hugely from violence," says Guidon.