flecheiros

"Mr. Possuelo's mission penetrated the vast Javari Valley Indigenous Land, 33,000 square miles of dense forest in the Upper Amazon where aerial reconnaissance showed at least 18 uncontacted tribes. Very little is understood about these people, including what ethnic groups they belong to and what languages they speak. One mysterious band is known by neighboring Indians as the flecheiros, Portuguese for "arrow people," for their rumored mastery of that weapon and their supposed ferocity."