The Kayapo (Portuguese: Caiapó ) people are the indigenous people in Brazil who inhabit a vast area spreading across the states of Pará and Mato Grosso, south of the Amazon River and along Xingu River and its tributaries. This pattern has given rise to the nickname the Xingu tribe. They are one of the various subgroups of the great Mebêngôkre nation (people from the water’s source). The term "Kayapo" is used by neighbouring groups rather than the Kayapo themselves. They refer to outsiders as "Poanjos". The type of sweet potato that forms an important part of the Kayapó diet is sometimes named "caiapo", after the tribe. It is cultivated under that name in Japan, and has been found to have health benefits. Location The Kayapo tribe lives alongside the Xingu River in the most east part of the Amazon Rainforest, in the Amazon basin, in several scattered villages ranging in population from one hundred to one thousand people in Brazil. Their land consists of tropical rainforest savannah (grassland) and is arguably the largest tropical protected area in the entire world, covering 11,346,326 hectares of Neotropical forests and scrubland containing many endangered species. They have small hills scattered around their land and the area is criss-crossed by river valleys. The larger rivers feed into numerous pools and creeks, most of which don’t have official names. In 2018, there was an estimated 8,638 Kayapo people, which is an increase from 7,096 in 2003. Subgroups of the Kayapo include the Xikrin, Gorotire, Mekranoti and Metyktire. Their villages typically consist of a dozen huts. A centrally located hut serves as a meeting place for village men to discuss community issues. Name The term Kayapo, also spelled Caiapó or Kaiapó, came from neighboring peoples in the early 19th century and means "those who look like monkeys". This name is probably based on a Kayapó men's ritual involving monkey masks. The autonym for one village is Mebêngôkre, which means "the men from the water hole." Other names for them include Gorotire, Kararaô, Kuben-Kran-Krên, Kôkraimôrô, Mekrãgnoti, Metyktire, and Xikrin. Appearance The Kayapo use intricate black body paint covering their entire bodies. They believe that their ancestors learned their social skills from insects, so they paint their bodies to mimic them and to better communicate with the Spirit that exists everywhere. The black body paint also allows them to blend into their surroundings when hunting in the forests.