Are you serious? The customs are based LOOSELY on real customs to become some bastardized mish-mash. The director went and lived for a short while with the Xingu tribe in the amazon. What does that mean? It means he saw them through the eyes of an outsider not as someone part of the culture. All what you see is his interpretation of what Xingu culture is: the taking of hallucinogens, marriage, women's dances, jagua painting and others. This does not even come close to true Xingu culture. (Btw I love how the tribes were really good African and modern dancers.) This is just the magical-childlike-Indian stereotype set in the Amazon.