
North Sentinel Island is in the Bay of Bengal, in the waters east of India. The Sentinelese inhabit the island and have an estimated population of anywhere from 50-500. They are aggressively defensive of their island and fend off visitors with arrows and stones and have even killed to keep visitors away from their home. After multiple failed attempts to communicate with the Sentinelese, the Indian Government has declared North Sentinel Island off -limits and has imposed a 3 mile no-trespassing boundary around the island.

A few days after the devastating tsunami in 2004, which killed more than 200, 000 and wiped out nearby islands, the Indian Government sent a helicopter to the island to
In 1981, the ship Primrose ran aground on the coral reef, which surrounds North Sentinel Island. A few days later, the crew noticed “small black men” carrying spears and arrows and building boats on the beach. Sensing imminent danger the captain radioed for Sentinelese could reach them. The tribe used scrap metal from the abandoned boat to build weapons and tools

In 2007, two fishermen fell asleep in their boat, anchored with a rock tied to a rope. The anchor failed and the boat drifted near the island and inside the coral reef. The Sentinelese promptly killed the men andburried them in shallow graves, giving others a grim warning sign to stay away from North Sentinel Island or risk death!
The dense forest canopy makes it impossible to get an accurate count of the tribe.
The Sentinelese survived the 2004 Indian Ocean earthquake and its after-effects, including the tsunami and the uplifting of the island. Three days after the event, an Indian government helicopter observed several of them, who shot arrows and threw stones at the hovering aircraft. Although the tsunami disturbed the fishing grounds of the Sentinelese, they appear to have adapted.
Since 1947, India has administered the island as part of the Andaman and Nicobar Islands Union Territory. However, because there has never been any treaty with the people of the island, nor any record of a physical occupation whereby the people of the island have conceded sovereignty, the island exists in a curious state of limbo under established international law and can be seen as a sovereign entity under Indian protection. It is, therefore, one of the de facto autonomous regions of India.

The Andaman and Nicobar Administration has stated in 2005 that they have no intention to interfere with the lifestyle or habitat of the Sentinelese and are not interested in pursuing any further contact with them. Wikipedia- North_Sentinel_Island
After the 2004 tsunami showed the dangerous tribal species, the world was still unaware of them: http://therednews.com/News/1913/indian-sentinel-island-where-untouched-human-living
