Scientists are using satellite images to get a better view of the location and size of isolated Amazon tribes living in dense forests along the border of Peru and Brazil.
The spacecraft are replacing surveys by invasive, low-flying aircraft that may scare people not accustomed to modern technology.
Analyzing images taken over a number of years by satellite cameras with 50-centimeter resolution, authorities in Brazil discovered five previously unknown villages along the Envira River.
Indigenous people, who have a subsistence lifestyle growing crops and hunting and gathering in the forest, have long avoided contact with the rest of the world. But their existence is severely threatened by illegal loggers and cocaine traffickers who, fleeing from authorities, keep moving their coca cultivation and processing plants deeper into the jungle.
Scientists say they have found obvious differences between the villages and contemporary camps of drug and timber traffickers. Some scientists have also expressed concerns that contact with the outside world may expose the tribes to germs against which they have no immunity.