The recent death of an American missionary on a remote Indian island has brought the world's untouched tribes into the spotlight. Commonly referred to as uncontacted or lost tribes, this small group of indigenous peoples face numerous threats from the outside world. There are currently thought to be around 100 tribes living completely cut-off from modern civilisation. Most of the tribes live deep in the Amazon rainforest, with others existing in the Congo, the mountains of New Guinea, and islands off the coast of India.

It's important to note that all of these tribes are likely to have come into contact with the world in some manner. Whether you're talking about planes flying overhead, inter-tribal trading, or lone missionaries, even the most remote tribes would be aware of the outside world in some way. According to Fiona Watson, research director for Survival International in an interview with the BBC, “They know far more about the outside world than most people think... They are experts at living in the forest and are well aware of the presence of outsiders.” 

Knowledge of these tribes comes from many sources, including aerial footage, reports from neighbouring tribes, and infrequent personal encounters. While the outside world has long been fascinated by people who live outside the reaches of conventional society, indigenous rights activists want these groups to be left alone in order to ensure self-determination and protection from modern diseases. Many of these tribes have only had a handful of encounters with western people, which means they're likely to lack immunity to everyday diseases such as the common cold.

There are thought to be between 70 and 80 lost tribes in the rainforests of Brazil, most of who have only a few hundred people or less per tribe. The Javari Valley in Brazil is particularly important, with this area about the size of Austria and home to 20 indigenous tribes. Of the 3,000 people estimated to live there, about 2,000 are likely to be uncontacted. Untouched peoples have also been found in other South American nations, including Bolivia, Colombia, Paraguay, Peru, and Ecuador. There are also three known uncontacted tribes living in Venezuela, although again, they may only account for a few hundred people.

While there are far fewer uncontacted tribes living outside South America, self-sufficient tribes are known to exist in New Guinea, the Congo, and islands off the coast of India. West Papua contains as many as 44 uncontacted tribes, with the mountainous terrain and evolution of multiple languages in the region helping tribes to stay isolated. The recent death of an American missionary has brought the Sentinelese people into global focus, with this isolated group in the Andaman Islands off the coast of India often called the most secluded tribe in the world. With a language that's distinct from other Andaman groups, the Sentinelese tribe may have been isolated for thousands of years. The Jarawas are another Andamanese tribe who live largely isolated from other peoples.  

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