We found fresh human tracks this morning. They all pointed in the same direction that we're walking through the virgin jungle of Brazil's westernmost Amazon Basin. Woolly monkeys hoot and chatter somewhere in the distance, their banter punctuated by the occasional zing of a machete and the shrill cries of screaming piha birds high in the canopy overhead. Our column of 34 men proceeds in silence, strung out single file far back into the forest. Only one or two companions are visible at any time in the blur of electric greens and rain-soaked browns. The rest are swallowed from view by a spray of overhanging branches and vines as thick as anacondas dangling a hundred feet from the treetops to the forest floor. Just ahead of me, Sydney Possuelo strides double-time across a stretch of level ground, a welcome break from the steep hillsides we've been scrambling over for days. "We're probably the only ones who have ever walked here," he tells me. "Us and the Indians."
A cantankerous iconoclast with bulging hazel eyes, scraggly salt-and-pepper beard, and wild locks flowing from beneath a floppy camouflage jungle hat, Possuelo, 63, is widely considered one of the Amazon's last great wilderness scouts and the leading authority on Brazil's remaining pockets of isolated Indians. After two weeks of river travel and 20 days of steady bushwhacking, Possuelo has led us into one of the most remote and uncharted places left on the planet, near the headwaters of two adjacent rivers, the Itaquaí and the Jutaí. This is the land of the mysterious Flecheiros, or Arrow People, a rarely glimpsed Indian tribe known principally as deft archers disposed to unleashing poison-tipped projectiles to defend their territory against all intruders, then melting away into the forest.
Suddenly Possuelo stops in his tracks. A freshly hacked sapling, still dangling by a shred of bark, lies across the path in front of us. In itself, the makeshift gate could not halt a toddler, much less a column of nearly three dozen armed men. But still, it bears a message—and a warning—that Possuelo instantly recognizes and respects. "This is universal language in the jungle," he whispers. "It means 'Stay Out. Go No Farther.' We must be getting close to their village."