Imagine living less than 30 miles from a massive and modern international port city and not having mastery of fire and zero knowledge of life outside of your 20-square mile island. That’s life for the few inhabitants of North Sentinel Island in the Indian Ocean, one of the last true uncontacted civilizations.
The uncontacted tribe we are looking at deals with much less interference than the Amazon tribes. There are three big reasons for this. First, the simple fact that the tribe is on a small, isolated island helps keep people from simply walking or driving to the Sentinelese.
Secondly, as we will look at more, the Sentinelese are exceptionally violent. In all but one known encounter, the Sentinelese have attacked visitors.
Lastly, the island itself has little in the way of resources for miners or loggers to bother about.
Put all of this together and the Sentinelese are one of the most isolated uncontacted tribes on earth. We have no notion of their language, what they call us or themselves, or how many there are.
Few missions to contact the Sentinelese are planned. They were believed to have been wiped out by the massive 2004 earthquake and tsunami, but helicopter surveys were met with the familiar arrow volleys. The tectonic activity helped the Sentinelese as it lifted the island a bit, adding more area and forming a land bridge to a very small island to the south. Estimates of their population range from only a few dozen to as many as a few hundred, we really have no good way to peer through the thick jungle to find out.
So they’re not as isolated as they sound, in all likelihood they had limited contact with nearby islands pre-colonization, this ultra-limited contact could have allowed them to absorb the concept of Dravidian kinship from the area around them.
What is Dravidian kinship? It is a form of kinship term grouping that seeks to distinguish cousins who are safe to be married from those who aren’t. It involves calling the partners your parents and grandparents could have married in each other’s families “mom” “dad” “gramma” and “grampa” in addition to your immediate grandparents and parents, and likewise calling their kids your siblings instead of just cousins. “Cousin” is a term for a relative who’s supposedly distant enough from you to avoid… consequences.
Tl;Dr, it is possible to “track” just how roll tide a possible match is and indeed some models of family term assignment are designed with keeping this track in mind, this would probably be how an isolated island would be avoiding bottlenecking. You’ll probably see this happen informally in isolated rural communities where “only a few families have lived here since prospector times!”