HONG KONG — Had a tsunami developed in the Indian Ocean after a massive earthquake on Wednesday, the world’s most isolated people would have been at serious risk. Perhaps, even, at risk of extinction.

The small tribe on North Sentinel Island continues to resist all contact with the outside world — just as they have for the past 60,000 years. They drive off fishermen, journalists, anthropologists and government officials with their spears and arrows. Their low-lying island, heavily forested and protected by a barrier of coral reefs, is roughly the size of Manhattan.

The tsunami warning on Wednesday was a false alarm. In 2004, however, it was initially feared that North Sentinel had been swamped by the killer tsunami that devastated the nearby Andaman and Nicobar Islands. When the Indian Coast Guard sent a helicopter to check on the Sentinelese, a single naked bowman emerged from the forest and fired arrows to drive the chopper away.

The Sentinelese had survived.

There are very few so-called “uncontacted tribes” still left — notably in the Amazon along the Brazil-Peruvian border and in the rainforests of West Papua.

“Perhaps no people on Earth remain more genuinely isolated than the Sentinelese,” according to Survival International, a group that advocates for the rights and privacy of aboriginal, endangered and uncontacted people.

The population of North Sentinel still can only be estimated — it’s perhaps as few as 50 or as many as 250 — and it’s not even known what the people call themselves. Their origins are uncertain, and their language is unintelligible to outsiders. They have fire, but it’s not clear whether they can make it themselves or have to wait for lightning strikes. They have fashioned hatchets from bits of iron that have washed up on their beaches. They apparently do not farm, and as hunter-gatherers they live mostly on fish, fruits, tubers, wild pigs, lizards and honey.

Do they have a religion? Do they write? Do they know envy, guilt, love, generosity? Do they spank their children? Do they sing? We simply don’t know.

India has sovereignty over North Sentinel, and for the past decade the Indian Navy has enforced a 3-mile buffer zone around the island to keep people away, especially meddling “ecotourists.” Even explorers and anthropologists are banned: Jacques Cousteau and the French ethnologist Claude Lévi-Strauss have been turned away.

All visits to North Sentinel have now ceased, although accidental encounters still occur. Two crab fishermen were killed in 2006 after they apparently got drunk, passed out, their anchor rope broke and their boat drifted into shore. The islanders buried the bodies on the beach and later turned away a rescue helicopter with their arrows.

With the other reclusive tribes in the Andaman and Nicobar Islands, bouts of measles, malaria and Hepatitis B have done the physical damage — most groups now have only a few dozen members. A controversial trunk road that cuts through Great Andaman Island, for example, has brought in poachers and tourism companies that bribe officials to conduct “human safaris” — their clients gawking at the local Jarawa people who now emerge from their forest preserve to beg for food alongside slow-moving buses.

The Observer newspaper recently acquired videos of bare-breasted Jarawa women being enticed by local police officers to dance for food. Two officers have been arrested and the road has reportedly been closed to tourists.

The Andamans were used by the British in the 19th century as penal colonies. When a Hindu convict escaped in 1896, he drifted 30 miles on a makeshift raft and washed up on North Sentinel. A search party found his body a few days later on a beach, punctured by arrows and his throat cut.

“After this, the island was left alone for nearly a century,” the U.S. historian Adam Goodheart wrote in a compelling account of the islands’ history and his visit there in 2000.

The North Sentinel islanders hid from an Indian government expedition that came ashore briefly in 1967. A subsequent landing party planted a stone marker that declared the island to be part of India. But it’s not at all clear that the islanders know what India is.

Small parties in the early 1970s were turned away by arrows. A documentary team and some police officers got the same fierce welcome in 1974: The film’s director took an 8-foot-long arrow in the thigh.

A brief video segment of that 1974 visit — the first recorded interaction with the Sentinelese — became part of a larger documentary, “Man in Search of Man,” about the world’s few remaining “lost tribes.” The Sentinelese portion of the film is here, beginning at 16:25.

Some government-sponsored groups made brief trips to the island in the late 1980s and early ’90s, largely under the direction of the Indian anthropologist T.N. Pandit.

“Sometimes they would turn their backs to us and sit on their haunches as if to defecate,” Mr. Pandit said in a 1994 interview with The Independent. “This was meant to insult us and to say we were not welcome.”

Mr. Pandit and his colleagues left gifts of coconuts, knives, cloth, candy, aluminum cookware, mirrors, rubber balls, beaded necklaces, plastic buckets. Once a live pig was left behind, staked to the beach. For some reason the islanders killed it and buried it in the sand.

The first time the Sentinelese did not carry weapons when approaching the outsiders came on Jan. 4, 1991, when 28 men, women and children waded out from the beach toward the motor launch.

“That they voluntarily came forward to meet us, it was unbelievable,” Mr. Pandit told Mr. Goodheart. “They must have decided that the time had come.”

As an anthropologist, Mr. Pandit told Mr. Goodheart, he was thrilled:

But there was this feeling of sadness also — I did feel it. And there was the feeling that at a larger scale of human history, these people who were holding back, holding on, ultimately had to yield. It’s like an era in history gone. The islands have gone. Until the other day, the Sentinelese were holding the flag, unknown to themselves. They were being heroes. But they have also given up.

They would not have survived forever — that, I can reason out. On a scientific basis, we can say that this population might have lived for another hundred years, but eventually . . .

In the 1974 film of North Sentinel, the narrator asks: “The Sentinelese don’t want to have anything to do with us. Are they right? Is the Stone Age preferable to the Nuclear Age?”

It’s a debate the Indian government has decided, at least for now: The Sentinelese are to be left alone.

What’s your view? Would the Sentinelese relinquishing their way of life be outweighed by the benefits they’d gain from antibiotics, air conditioning, heart surgery, chainsaws, motorboats? Would their lives be elevated by an exposure to Shakespeare, Chartres and Messi, Caravaggio, coq au vin and “Casablanca”? Or should they be left entirely alone, unobserved and unstudied — to prosper, or to die out, or merely to live on their island as they always have?