Tom Acres, news reporter

In a world more connected than ever - with dozens of social networks and messaging apps travelling in our pockets wherever we go - it is easy to forget just how many people still shun modern society in some of the most isolated places on the planet.

But the release of extraordinary footage of an indigenous man who has lived alone in the Amazon rainforest for more than two decades has served as a timely reminder - and rekindled our fascination with the world's uncontacted tribes.

Sole survivor of Amazon tribe filmed

There are thought to be such groups spread across multiple countries and continents, from the deep, dense forests of the Amazon in Brazil, to the mountains of New Guinea.

But with members of these indigenous populations unlikely to add you on Facebook anytime soon, it is simply impossible to know their true numbers.


With that in mind, just what do we know about the world's uncontacted tribes?

Image: Members of the Mashco-Piro tribe at the Manu National Park in southeastern Peru

Where are they?

Survival International - a charity dedicated to helping indigenous people "defend their lives, protect their lands and determine their own futures" - reports the presence of uncontacted tribes in West Papua in New Guinea, and on the island of North Sentinel, which is located among the Andaman and Nicobar Islands of India.

The tribes of West Papua are believed to be present in the Gusawi region.

Those on North Sentinel are known as the Sentinelese, and Survival estimates there are between 50 and 200 people who make up the group.

Image: The remote North Sentinel Island

Uniquely, they are known to be hostile to outsiders, attacking anyone who goes near them. Most tribes attempt to remain hidden from any interference rather than engaging with it.

The numbers in New Guinea and India pale in comparison to South America, with the vast majority of uncontacted tribes known to live in the Amazon.

Brazilian government agency Funai, which is dedicated to protecting the interests and culture of the country's indigenous population, believes there are 113 tribes in Brazil alone.

More than a dozen are thought to be in Peru, with others in Bolivia, Colombia and Ecuador, many with their own unique hunting tactics and languages. Their presence is becoming increasingly known as more of the rainforest is destroyed.

New Scientist reports that there may also be some uncontacted tribes in Malaysia and central Africa

Image: Members of a previously uncontacted tribe make voluntary contact with Funai researchers

Who are they?

Less is known about the tribes of West Papua than just about any in the world.

New Guinea is an Indonesian territory and it has been extremely difficult for human rights organisations and journalists to visit, with the treacherous terrain among which the tribes are thought to live making them hard to reach.

Information about the Sentinelese is a little more readily available.

Survival International describes them as a "hunter-gatherer society with no known agriculture", making use of metal tools fashioned from nearby shipwrecks.

Image: The Sentinelese live on the Andaman and Nicobar Islands of India. Pic: Smithsonian Institution

No official attempt at contact has been made since 1996, partly to protect the tribe - but also because they have a tendency to shoot arrows at those who approach.

Among the tribes that call the Amazon their home are the Cacataibo, thought to live in central Peru, and a whole host believed to be in Brazil.

These include the Karafawyana and the Waorani, who live near Yasuni National Park and regularly find themselves at risk of oil companies and loggers.

Brazilian tribes are extremely varied in terms of lifestyle - some are nomadic hunters and gatherers, while others live as farmers, planting fruits, vegetables and other crops.

Of all the world's uncontacted tribes, those in the Amazon are most at risk due to ongoing deforestation.

Image: Deforested jungle inside the Ashaninka Indian territory in Brazil's Acre state

Why do they remain isolated?

Some are left alone because it is the policy of the country's government to do so; Funai in Brazil is a good example.

In 2015, US academics Robert S Walker and Kim R Hill published an article in Science magazine claiming that there were many benefits of seeking contact with the tribes, but Funai dispelled the idea as "arrogant and dangerous".

Before Funai was set up in 1987, the Brazilian government had tried - unsuccessfully - to aggressively relocate tribes who stood in the way of commercial ventures in the Amazon.

Image: Tribesmen on the bank of the Envira river in Aldeia Simpatia, Brazil

The continued solitude of many tribes is mostly down to the will of the tribes themselves. With so many having been wiped out by the actions of outsiders over the years, those who survive fear being discovered.

That could be due to the threat of violence, or perhaps disease. Being cut off from the rest of the world means they would have no resistance to diseases such as flu.

It all means that most observations of uncontacted tribes are now made from a distance, such as via helicopter.

Image: Members of an uncontacted Amazon basin tribe pictured from a flight over the Brazilian state of Acre

How long do they have?

Indigenous tribes have faced threats for generations - and Survival International describes those who remain uncontacted as "the most vulnerable peoples on earth".

The charity lists disease, loggers and the construction of roads as some of the biggest threats to their way of life.

"Outsiders want their land or its resources, for timber, mining, dam or road building, ranching, or settlement," it says.

"Contact is usually violent and hostile, but the main killers are often common diseases to which the uncontacted people have no immunity and which often prove fatal."

Image: Deforestation remains a huge threat to the tribes of the Amazon

Writing for The Huffington Post last year, actor and activist Sir Mark Rylance said uncontacted tribes would only survive through "a global outcry and sustained pressure on governments, multinationals, and international bodies like the UN".

And history provides plenty of evidence of indigenous people being threatened by outsiders.

But Survival International says the new footage released from the Amazon presents hope for the future.

Fiona Watson, the charity's research and advocacy director, told The Guardian: "The fact he is still alive gives you hope.

"He is the ultimate symbol, if you like."