There are an estimated 15,000 cultures remaining on earth, many doomed or significantly threatened by erosion of cultural integrity, loss of habitat and environmental quality, and the ravages of disease and socio-economic infections. Most of the 15,000 cultures are represented by a single population of several hundred persons or less, dependent on pockets of land which are increasingly under threat from other uses or environmental destruction. They lack immunity from many Western diseases, modern weapons to defend themselves from armed intruders like drug smugglers and illegal loggers, and a voice in national politics. With their demise goes expertise and wisdom of elders, healers, midwives, farmers, fishermen and hunters, mostly transmissible only by oral tradition to respectful successors.
There are still groups living beyond the reach of the global economy, in places like the Andaman Islands in the Indian Ocean and the mountains of New Guinea. The pygmies, who live in the equatorial forests of Uganda and Zaire, are on the verge of extinction; possibly 300 are left and the numbers are dwindling.
The planet’s largest and most diverse isolated cultures are centered in the Amazon, primarily in western Brazil and eastern Peru. Since 1900, 90 of Brazil's 270 Indian tribes have completely disappeared, while scores more have lost their lands and abandoned their ways. More than two-thirds of the remaining tribes have populations of fewer than 1,000.
Brazil and Peru have taken radically different approaches toward isolated peoples in the Amazon although both nations see the Amazon as a treasure house of oil, timber and gold. Brazil has pursued the sort of engagement pioneered by late 19th-century missionaries. Officials built small frontier posts in the jungle, planted gardens and let tribes gather the harvest. Enticed into contact, the isolated people would trade ornaments and forest products for metal tools and objects and be drawn gradually into the labor force, often created debilitating dependence. Peru, by contrast, has only recently admitted that its isolated peoples even exist. As recently as 2007,the president dismissed “the figure of the uncontacted native jungle dweller” as a fiction created by zealous environmentalists. Either way, the region has seen massive death of isolated peoples due to abrupt contact with resource developers and forest depletion. Two continent-wide projects crossing Brazil and Peru — the $2.8 billion, 1,600-mile Interoceanic Highway and the Chinese-sponsored $10 billion, 3,300-mile Twin Ocean Railroad — would plough through tropical savanna and thick forest, home to hundreds of indigenous communities.