Most of the population of the Andaman Islands are people from the mainland, primarily West Bengal and Tamil Nadu. The natives of the Andaman and Nicobar Islands are endangered tribal groups, such as the Jarawa, Sentinelese, Shompen, Onge and the Great Andamanese. They are anthropologically-significant as some of the world's most primitive tribes. Most have maintained their lifestyle for centuries, and government policy is one of non-interference. Most of the native islanders reportedly survived the tsunami because they lived on higher ground or far from the coast. The Onge (with a 2001 census population of 96), Jarawa (240), Sentinelese (39) and Great Andamanese (43) were reached by survey teams. The Sentinelese, on an island reserve, are hostile to outsiders and shot arrows at helicopters sent to check on them. On the Nicobar Islands the Nicobarese, a tribe with a Southeast Asian heritage (2001 population 28,653), lost about 656 lives with 3,000 missing. Surveys were conducted on the Shompen (2001 census count of 398) located on Great Nicobar island.