KONABUMA-TERI, Venezuela -- Gripping bows and long, slender arrows -- one for shooting animals and one for shooting birds -- the Yanomami hunters emerged from the Amazon underbrush to inspect a Super Puma helicopter that had clattered out of the skies into their village.
"No visitors ever came here," Wakamanawa, the head man, explained to Napoleon A. Chagnon, a U.S. anthropologist who was the first non-Yanomami to visit this village in the remote highlands of southern Venezuela.
In two recent expeditions, Mr. Chagnon and Charles Brewer-Carias, a Venezuelan naturalist, discovered 10 Yanomami villages they say have never been contacted before by the outside world. Traveling on foot and by helicopter, they visited three of the villages.
"It will be one of the last such experiences in the 20th century," Mr. Brewer-Carias said at the end of the expedition. "We are rapidly approaching the 500th anniversary of the discovery of the Americas, and the Yanomami are the largest uncontacted group in the Americas."
The expedition is part of a Venezuelan effort to survey the Yanomami and their Amazon lands with a goal of creating a tribal reserve.
After ignoring the Yanomami for centuries, Venezuelans have been spurred to action by recent reports of physical decimation and cultural disruption of the Yanomami in Brazil, where the tribe does not have a reserve. In Brazil, thousands of gold miners entered Yanomami lands in the late 1980s. Recently, the invasion spilled through the unmarked jungle into Venezuela.
Seeking to avert a repetition of the Brazilian experience and to protect Venezuelan sovereignty, Venezuela's government expelled hundreds of miners and in June inaugurated an army post to patrol the border area.
Venezuela's president, Carlos Andres Perez, has expressed interest in creating a tribal reserve to protect a large part of the estimated 14,000 Yanomami in his country.
The survey has reached into one of the least explored regions of South America, the Siapa River Valley.
Lifting off recently from Puerto Ayacucho, the capital of Amazonasterritory, the Venezuelan air force helicopter quickly left behind a few farm fields clinging to the banks of the Orinoco River.
Outfitted with two extra fuel tanks, the helicopter flew due south, toward an area marked on aeronautical charts with "relief data unreliable."
Flying in the several hundred feet of airspace between low cloud cover and forest canopy, the helicopter passed black granite cliffs that rose sharply from the forest floor.
Below was a sea of rain forest, broken occasionally by slow-moving, chocolate-colored rivers.
Studying a radar survey map, Juan Carlos Ramirez, the expedition's logistician, identified mountain ranges -- some as high as 7,000 feet.
After a four-hour flight, Konabuma-teri was spotted, crated in a bowl of mountains about 1 degree north of the equator. In late August, the scientists discovered the village after nine hours of crisscrossing the uncharted area by helicopter.
"I had long thought that Konabuma-teri was a mythical village," recalled Mr. Chagnon.
Mr. Chagnon has studied the Yanomami in Venezuela since 1964. His classic text on the tribe, "Yanomamo: The Fierce People," has been read by thousands of U.S. college students.
The largely unexplored Siapa River Valley may contain as many as 3,500 Yanomami, considered to be the largest tribe in the Amazon still living according to Stone Age ways.
In August, the scientists visited two other uncontacted villages, Doshamosha-teri and Narimobowei-teri.
A handful of industrial goods -- cloth gym shorts and Brazilian cruzeiro coins -- had entered this "Shapono" or village through trade ties with Yanomami on the other side of the mountain range in Brazil.