The Flecheiros live in the far west of Brazil, in the Vale do Javari Indigenous Territory, an area covering 83,000 square kilometres (32,000 sq mi).
Contact with uncontacted peoples is prohibited by the government of Brazil, even with respect to other indigenous groups living traditional lifeways, but state capacity is low in these areas and monitoring or enforcement is difficult.
[1] Little is known about the Fleicheros due to their apparent preference not to engage with the world community and the Brazilian government's policy of preventing contact by outsiders.
They cultivate rocas - temporary jungle plantations used for a few years at a time - to grow sugarcane, cotton (with which to pack blowguns), manioc, and plantains.
[1] The Flecheiros make earthenware pottery and appear to have some limited access to metal tools, likely taken from loggers and fisherman illegally encroaching on their territory.
[1] They build palm-thatched huts called malocas in communities of about 50-60 people and make use of sleeping hammocks like many Amazonian tribes.
The Flecheiros are the subject of a book called The Unconquered: In Search of the Amazon's Last Uncontacted Tribes, by Scott Wallace.