The Sentinelese appear to have split off from the rest of humanity approximately 48,500 years ago, and aside from occasional contact with other members of the Andaman islands, have remained isolated ever since.
People have occasionally landed on or near Sentinel island, but the islanders have all resisted contact, generally by shooting arrows at anyone who gets too close. Even National Geographic hasn’t got any pictures of them–when they tried to make a documentary on the island, armed with gifts, they had to retreat after the director took an arrow in the thigh. The last guys whose boat accidentally drifted onto their beach got killed and buried in shallow graves on the beach.
North Sentinel Island is technically owned by India, but India has given up trying to make peaceful contact, and it would probably look bad to just bomb the place.
So what do we know about the Sentinelese?
Obviously not a whole lot, since most of what we know of them has been observed from a distance.
The whole island is about the size of Manhattan, and probably inhabited by 40-500 people. They’re generally characterized as Negritos, a term used for the shorter than average but taller than Pygmies, dark-skinned people of the Andaman Islands and certain groups in the Philippines, Thailand, and Malaysia. The term is only descriptive; different Negrito tribes may not be related to each other at all. (I promised I’d get around to the Negritos eventually.)
Aside from stuff that has randomly washed up on their island or was given to them by folks trying to make contact, they have only stone tools and, according to the Wikipedia, appear not to have fire.
But a little more research suggests that Wikipedia may just be wrong on this point; during the search for the lost Malaysian jetliner, smoke was observed rising from North Sentinele, which implies that the people there probably do have fire.
At any rate, we do know that they have bows and arrows, boats, and spears.
When National Geographic tried to make contact, they left a plastic toy car, coconuts, a live pig, a doll, and aluminum cookware on the beach before getting shot at. After they retreated, they observed the Sentinelese shoot and bury the pig (not eat it?) and, if the Wikipedia is accurate, shoot and bury the doll. They took the coconuts and pans; no word of the car’s fate.
In 1970, a group of Indian anthropologists that came near the island had a decidedly strange incident:
Quite a few discarded their weapons and gestured to us to throw the fish. The women came out of the shade to watch our antics… A few men came and picked up the fish. They appeared to be gratified, but there did not seem to be much softening to their hostile attitude… They all began shouting some incomprehensible words. We shouted back and gestured to indicate that we wanted to be friends. The tension did not ease. At this moment, a strange thing happened — a woman paired off with a warrior and sat on the sand in a passionate embrace. This act was being repeated by other women, each claiming a warrior for herself, a sort of community mating, as it were. Thus did the militant group diminish. This continued for quite some time and when the tempo of this frenzied dance of desire abated, the couples retired into the shade of the jungle. However, some warriors were still on guard. We got close to the shore and threw some more fish which were immediately retrieved by a few youngsters. It was well past noon and we headed back to the ship…
Virtually nothing is known about the Sentinelese language, though it is speculated that it is related to the Onge language of the Andaman islands. However, attempts at using the Onge as translators have failed, as the Onge themselves cannot understand a word of Sentinelese.
A British expedition in the 1880s that got a decent look at the island claimed that, of all the nearby groups, Sentinelese culture most closely resembled Onge culture, so it is still possible that the languages are related, albeit distantly.
Since much more is known about the Onge, I’m going to speak briefly about them:
The Onge are marked in blue on the map above; today they live chiefly on Little Andaman Island in the south, but in the past they ranged further north, closer to to the Sentinelese. Contact with the outside world has reduced their population from almost 700 people (1900) to about 100. (There may well have been >700 people before 1900, that’s just the first date I have numbers for.) Strangely, the Onge appear to be the world’s least fertile people, with 40% of couples suffering infertility. Wikipedia estimates their Net Reproductive Rate (similar to TFR, but only looks at daughters) at 0.91, which is below replacement, however, their population appears to have held steady for the past 30 years, so perhaps the problem is working itself out.
Why such infertility? The most obvious guesses (IMO) are some sort of environmental poison/effect; some sort of diseased-induced infertility, like gonorrheal scaring (please note that I have no idea if any of the Onge have ever had gonorrhea, but it is a common cause of infertility;) or a side effect of inbreeding/lack of genetic diversity following their extreme population collapse.
The article Malnutrition and high childhood mortality among the Onge tribe of the Andaman and Nicobar Islands suggests that the real cause of the low NRR is high childhood mortality due to malnutrition/insufficient food, probably due to loss of their traditional hunting/gathering grounds.
Genetically, the Onge appear to have been isolated for an extremely long time. They all share the same mitochondrial DNA, haplotype M32, which is not found anywhere outside of the Andaman Islands. (The larger umbrella-group M, to which all M-varieties belong, is one of the world’s most wide-spread lineages, emerging either shortly before the Out of Africa event, or shortly after it, but is most reliably concentrated in Asia, with several ancient lineages in India.)
The Onge language is related to the languages of some of the other tribes in the Andaman Islands, and speculated to be part of the greater Austronesian language family. (Considering that the whole Indo-European language family is about, what, 4-6,000 years old, I am a little skeptical of our ability to reconstruct too much about a language that may have diverged 40,000+ years ago.)
Onge Y-DNA belongs to Haplogroup D-M174, which emerged in Asia about 60,000 years ago and isn’t found outside of Asia. It is found today among Tibetans, the Ainu, and the Andaman Islanders, suggesting that these people are all (at least partially) descended from a common source that split off from other humans around 60,000 years ago, or just after the OoA (relatively speaking.) D-M174 is also found in small amounts in China and central/east Asia.
The Ainu, IIRC, also have a particular tooth shape that is commonly found in Melanesia, but not outside of it, and a small amount (about 15%, I think,) of Siberian DNA. And, of course, we now have evidence of Melanesian DNA showing up in the Amazon rainforest, not to mention the curious concentration of archaic Denisovan admixture in Melanesians, despite the only Denisovan remains we’ve found so far coming from Russia. However, it appears that there is no Denisovan DNA in the Andaman Islanders, so maybe they split off before the Denisovan admixture advent.
The sum of the evidence suggests a single band of people, perhaps most closely resembling the Negritos, spread 60,000 years ago along the coast of southern Asia and spread far into the interior, reaching at least as far as Tibet, the Andaman Islands, and northern Japan, and possibly even crossing the Bering Strait and down to the tip of South America. (Since Melanesians do not appear to have ever spread to Polynesia, I suspect they did not boat straight across the Pacific, but maybe we just haven’t yet found Melanesian remains in Polynesia.)
Over the ensuing millenia, later population waves, like the Polynesians and the common ancestors of east Asians like the Han and the Japanese, migrated into the area, leaving only a few isolated remnants of Haplogroup D-M174 in far-flung, difficult to reach places like the Andaman islands, the Himalayan Plateau, and the coldest parts of Japan. Likewise, Melanesian DNA in the New World seems to have best survived in one of its harshest, most difficult to penetrate habitats: the rain forest.
This all gets back to my theory of genetic survival at the fringes, (discussed here,) which I hope to devote a full post to soon. The history of the world is the group with better tech conquering the group with worse tech, and then getting conquered in turn by a group with even better tech.
The island of Taiwan illustrates this well; the most recent immigration wave happened in 1949, when the ROC lost their war with the PRC and evacuated 2 million of their people to Taiwan, a nation of 6 million at the time. Taiwan had previously (temporarily) been conquered by the Japanese, and before that, by other Chinese people, who began arriving around 1300. They’ve been gradually defeating/replacing the aboriginal Taiwanese, who are now a very small population, and the aboriginal Taiwanese themselves have legends about having wiped out a negrito-like people who predated their arrival, but I consider such legends only potentially true. Each group got conquered by the next group with better tech.
A couple more pictures of Andaman Islanders:
Anyway, back to the Sentinelese.
The available evidence suggests that they split off from the rest of the human population ages upon ages ago, and have been effectively isolated from everyone but their immediate neighbors ever since. Though technically their island is considered part of India, as a practical matter, they govern themselves. They have managed to retain their independent status for so long by living on a tiny, hard-to-reach island and enforcing a strict immigration policy of killing anyone who shows up on their beach.
Given that the Sentinelese would probably all die of the common cold if they ever did let foreigners onto their island, their policy is not unreasonable. You wouldn’t want to let some plague-bearing foreigner kill you with their germs, either. Unfortunately, the disease situation is unlikely to reverse itself; their population is just too small to withstand contact with the outside world. Too-long isolation in such a tiny place has cut them off from all the technological progress of the past 40,000 to 60,000 years, and their population is too small to develop much tech internally. To be fair, their strategy has worked so far. But now they’re stuck, maintaining their tiny island against the odds until someone decides to show up with guns and do some logging, fishing, or whatever they feel like, at which point there’s a good chance they’ll be wiped out.
Long term, total isolation is a policy with very low survival odds.
After some thought, the best option I can think of for the Sentinelese, other than continuing as they are and hoping for the best (after all, the rest of the world could destroy itself in a nuclear holocaust and leave them behind to continue doing their thing for the next 40,000 years,) is to expand their numbers and send excess people to the other Andaman Islands. Sure, most of those people would probably get colds and die, and if not the colds, alcohol’s a likely culprit, but as long as they keep exporting people, eventually some of them will survive, and create a breeding population/intermix with the other Andamanese until they have the numbers/immunity to interact with the outside world.