The Brazilian government used to conduct "first contact" expeditions to find these tribes, believing that this was the best way to protect them. But they've since discontinued these expeditions in favor of the occasional status flyover.
FUNAI seeks to protect these uncontacted tribes, as well as other indigenous people of the Amazon River Basin, with infrequent flyovers, checking to see if they've moved locations or if loggers are illegally encroaching on their lands.
But in Amazonian countries with fewer resources to police the region, like Peru — home to some 15 identified uncontacted tribes — conservationists struggle to protect the region and its isolated inhabitants from loggers and prospectors.
Source: National Geographic
Unfortunately, their isolation means they're susceptible to diseases from the outside world.
It's part of the reason why anthropologists and indigenous-rights advocates support their continued isolation.
But these tribes are part of our shared humanity, and their unique cultures are worth preserving and protecting, too.
Read next on Business Insider: This isolated tribe has rejected contact for centuries and remained hostile toward outsiders