"Their awareness of the ocean, earth, and the movement of animals has been accumulated over 60,000 years of inhabiting the islands. Oral history teachings and their hunter-gatherer lifestyle might have prepared them to move deeper into the forests after they felt the first trembles of the earthquake. . .

The tribes present something of an enigma to anthropologists. The four Andaman tribes—the Great Andamanese, Onge, Jarawa, and Sentinelese—are known as the Negrito tribes and are of African descent. [Editor's Note: DNA evidence suggests these people might be the ancestors of some of the earliest humans to come out of Africa. Some scientists believe the Negrito residence in the islands goes back more than 30,000 years, possibly as far back as 60,000 years.] Those living on the Nicobar Islands—the Shompen and Nicobarese—are of Asian descent."

source: http://news.nationalgeographic.com/news/2005/01/0125_050125_tsunami_island.html