Although the villages are mostly hidden from view, many people live along the Napo, with varying degrees of "tradition." In the Yasuni National Park, there is one tribe that has cut off all contact with the outside world, up to and including killing those who trespass. The actual boundary is not clear, so most stay away entirely.

Much of the traffic on the river comes from the oil companies. This is an ecosystem that is sitting on a razor's edge: Ecuador desperately needs the money from the oil, but the usual methods of extraction could be disastrous.