Kajkwakratxi

The Tapayuna, who call themselves Kajkwakratxi, are a Northern Jê people of Mato Grosso, whose forest homeland lay on the Arinos river in the Tapajós basin. Their language is close to that of the Kĩsêdjê, or Suyá, and neighbours called them the Western Suyá or Beiço-de-Pau, meaning wooden lip, after the lip disks worn by their men.

They were mostly monogamous, though a shaman might take two wives, and a new husband went to live in his father-in-law's house.

Their forests held rubber trees, ores and hardwoods, but through the 1700s and 1800s the Tapayuna remained in their river villages, hunting, fishing and farming beyond the reach of the Portuguese frontier, whose soldiers, missionaries and slavers never established a lasting presence on the Arinos.