the first millennium, South America's vast rainforests,
mountains, plains, and coasts was the home of millions of
people. Estimates vary, but 30-50 million are often given and
100 million by some estimates. Some groups form permanent
settlements. Among those groups are the Chibchas (or "Muiscas"
or "Muyscas"), Valdivia and the Tairona. The Chibchas of
Colombia, Valdivia of Ecuador, the Quechuas and the Aymara of
Peru and Bolivia are the four most important sedentary
Amerindian groups in South America. From the 1970s, numerous
geoglyphs have been discovered on deforested land in the Amazon
rainforest, Brazil, supporting Spanish accounts of a complex,
possibly ancient Amazonian civilization.
The theory of
pre-Columbian contact across the South Pacific Ocean between
South America and Polynesia has received support from several
lines of evidence, although solid confirmation remains elusive.
A diffusion by human agents has been put forward to explain the
pre-Columbian presence in Oceania of several cultivated plant
species native to South America, such as the bottle gourd (Lagenaria
siceraria) or sweet potato (Ipomoea batatas). Direct
archaeological evidence for such pre-Columbian contacts and
transport have not emerged. Similarities noted in names of
edible roots in Maori and Ecuadorian languages ("kumari") and
Melanesian and Chilean ("gaddu") have been inconclusive.
A 2007 paper published in PNAS put forward DNA and
archaeological evidence that domesticated chickens has been
introduced into South America via Polynesia by late
pre-Columbian times. These findings are challenged by a later
study published in the same journal, that cast doubt on the
dating calibration used and presented alternative mtDNA analyses
that disagreed with a Polynesian genetic origin. The origin and
dating remains an open issue. Whether or not early
Polynesian–American exchanges occurred, no compelling
human-genetic, archaeological, cultural or linguistic legacy of
such contact has turned up.
Norte Chico or Caral