Brazil’s decision in recent weeks to release video clips of isolated indigenous peoples reflects a growing unease among rights officials that time may be running out to protect the Amazon’s last “uncontacted” tribes and their rain forest homelands.

Since July Brazil’s indigenous affairs agency, FUNAI, has made public two videos recorded during field expeditions to monitor and protect indigenous people living in reserves closed off to the outside world.

In the first, a robust man is seen chopping down a tree deep in the forest. It was taken surreptitiously from a short distance by a FUNAI team in charge of protecting him. The man has been living alone for the past 22 years in the 30-square-mile Tanaru Indigenous Land, in Brazil’s