Why North Sentinel Island Is One Of Earth’s Last Great Mysteries—Officially Off-Limits Since 1956

John Allen Chau, a 26-year-old American missionary paddled his kayak toward North Sentinel Island on the morning of November 16, 2018. The shoreline was silent—just the lapping waves and a distant seabird’s call.

Chau had already tried twice before. The previous morning, he had approached the huts, calling out in English, hoping to make contact. The Sentinelese fiercely drove him away, shouting at him from the shore. Later that day, on his second attempt, a “young boy” shot an arrow at him, striking his waterproof Bible. He had retreated then, shaken but not discouraged.

Now, the next day, he pressed on. The fishermen who had brought him this far—illegally, for ₹25,000 ($285)—watched uneasily from a distance. The Indian government had banned all contact since 1956 to protect both outsiders and the tribe itself.

But Chau had made up his mind. He stepped onto the island.

Minutes later, figures emerged from the trees. The fishermen saw his body dragged across the beach and buried in the sand.

But North Sentinel Island’s 1956 Ban Wasn’t Just About Keeping Outsiders Safe

Chau, driven by missionary zeal, likely intended no harm to the Sentinelese people. However, he overlooked a critical aspect of their existence.

Anthropologists estimate that the inhabitants of North Sentinel Island have lived in near-total isolation for tens of thousands of years. This prolonged isolation means the Sentinelese have had no exposure to many pathogens common in the outside world. Their immune systems are unprepared for such diseases, making them highly vulnerable to illnesses that outsiders might inadvertently introduce.

Evidence from other isolated tribes shows that contact can have devastating effects on their health.

In the early 1980s, oil exploration crews pushed into the Peruvian rainforest, bringing with them more than just machinery. Within months, over half of the previously uncontacted Nahua tribe had died, wiped out by diseases their immune systems had never encountered.

A decade later, in the mid-1990s history repeated itself. Illegal mahogany loggers forced contact with the Murunahua people, also of Peru. The result? Another wave of disease, displacement and death, as once-thriving communities were decimated by infections introduced from the outside world.

For isolated tribes, contact isn’t just a risk—it’s often a death sentence.

Recognizing this vulnerability, the Indian government implemented The Andaman and Nicobar Islands (Protection of Aboriginal Tribes) Regulation, 1956. This law prohibits travel to North Sentinel Island and any approach closer than five nautical miles, aiming to safeguard the Sentinelese from potential exposure to infectious diseases against which they have no immunity.

However, the reasons behind the enactment of The Andaman and Nicobar Islands (Protection of Aboriginal Tribes) Regulation, 1956 go beyond just disease prevention:

• Preserving cultural heritage and traditional lifestyles. The regulation protects the tribes from external influences that could disrupt their centuries-old way of life, ensuring their customs, languages and traditions remain intact.
• Preventing exploitation and encroachment. Outsiders could exploit the tribes for tourism, research, or resource extraction. The law prohibits land grabs, forced contact and unauthorized access to protect their autonomy.
• Banning illegal activities and unwanted surveillance. The regulation prevents poaching, human trafficking, unauthorized filming and exploitation of these tribes, reinforcing strict legal protections and penalties for violators.

North Sentinel Island And It’s People—What We Do Know

The Sentinelese, inhabitants of North Sentinel Island—a tiny, forested landmass adrift in the Bay of Bengal—have lived in isolation for tens of thousands of years. Roughly 60 square kilometers (~23 square miles) in size, the island is densely covered in tropical rainforest, with no visible signs of agriculture or large-scale settlements. A thin strip of white-sand beaches encircles the land, broken only by the jagged remains of dead coral reefs, which serve as a natural barrier against boats.

Unlike many of the other Andaman Islands of India, North Sentinel is untouched by modern infrastructure—no roads, no harbors and no airstrips. From above, North Sentinel Island looks untouched—just dense jungle stretching to the shoreline. But faint, narrow trails cut through the trees, subtle traces of the Sentinelese moving within.

The Sentinelese are believed to be direct descendants of the earliest human populations to emerge from Africa and settle in different parts of the globe. Isolated ecosystems, like North Sentinel Island, often lead to unique evolutionary paths.

For instance, on islands off the coast of California and Mexico “hyper-defensive rattlesnakes” and “silent rattlesnakes” evolved very distinct characteristics compared to their mainland relatives, evidently due to their isolation. Similarly, the Sentinelese have developed a way of life entirely their own, untouched by modern civilization.

What We Know About The Sentinelese (Mostly) Comes From One Man—Triloknath Pandit

Indian anthropologist Triloknath Pandit dedicated years to understanding the Sentinelese, one of the last uncontacted tribes on Earth. His first expedition to North Sentinel Island in 1967 marked the start of a series of attempts to cautiously observe their way of life. At the time, knowledge of the Sentinelese was scarce, aside from reports of their fierce rejection of outsiders.

For decades, Pandit and his team carefully approached the island’s shores, leaving behind small gifts—coconuts, bananas, and metal tools—hoping to foster trust. The Sentinelese reacted unpredictably. Sometimes, they would take the offerings after the visitors departed. Other times, arrows would fly from the treeline, a clear warning to stay away.

Then, on January 4, 1991, something unexpected happened. A group of Sentinelese walked out from the jungle and waded into the water—unarmed. For the first time, they accepted coconuts directly from Pandit’s team. Some tucked them under their arms as if they were prized possessions.

Yet, the moment was brief.

Speaking to BBC, Pandit recounted, “When I was giving away the coconuts, I got a bit separated from the rest of my team and started going close to the shore. One young Sentinel boy made a funny face, took his knife and signaled to me that he would cut off my head. I immediately called for the boat and made a quick retreat. The gesture of the boy is significant. He made it clear I was not welcome.”

In later encounters, the tribe resumed its defensive posture, firing arrows to deter outsiders. Pandit saw this not as hostility, but as a necessary act of self-preservation—a reaction shaped by past conflicts with outsiders.

Much of what is known about the Sentinelese—how they look, the tools they use, and the glimpses of their behavior—comes from Pandit’s fieldwork. His observations were later documented in reports by the Anthropological Survey of India. Yet, despite his efforts, the Sentinelese remain an enigma—their language unclassified, their customs a mystery, their way of life largely unchanged for thousands of years.

And that’s exactly how they want it to stay. The Indian government, it seems, agrees—an amendment in 2010 only strengthened the ban, tightening restrictions to ensure the Sentinelese remain undisturbed.

While the Sentinelese people have remained untouched by modern civilization, most of us in the globalized world have drifted further from nature than we realize. Take this free, science-backed Connectedness to Nature Scale to learn more about your relationship with nature.