BRASILIA, Jan 24 (Reuters) - The main organization representing Brazil's 300 indigenous tribes said on Friday it would sue far-right President Jair Bolsonaro for racism after he said indigenous people were "evolving" and becoming more human.

"We need to put a stop to this perverse man," Sonia Guajajara, leader of the Association of Indigenous Peoples (APIB), wrote on Twitter. "APIB will go to court against Jair Bolsonaro for the crime of racism."

Racism is considered a serious crime in Brazil and can carry a sentence of up to five years.

The controversial comments, the latest in a series of presidential outbursts on Brazil's tribes, came in a video posted on social media on Thursday.

"The Indian has changed, he is evolving and becoming more and more, a human being like us," Bolsonaro said. "What we want is to integrate him into society so he can own his land."

The presidency did not immediately respond to a request for comment on the potential lawsuit.

Bolsonaro has previously said indigenous reserves are too large and his government wants to allow commercial mining and agriculture on these reservations.

He has said they live in poverty like "animals in zoos" and wants to assimilate them into Brazilian society and economy. Tribal leaders decry this as planned ethnocide aimed at eliminating their cultures.

A former army captain who was a congressman for 28 years before becoming president, Bolsonaro has a history of making racist, misogynist and homophobic statements.

He once said on the floor of the lower house that Brazil should have followed Colonel George Armstrong Custer's example in dealing "efficiently" with indigenous peoples in the United States.

Brazil has some 850,000 indigenous people, most of whom live on reservations that account for 12% of the national territory in Latin America's largest country.

Bolsonaro has said he will not approve "a single centimeter" more of indigenous land claims and has suggested that some of the larger reservations could have their boundaries reviewed.

Environmentalists warn that these moves to assimilate indigenous peoples could speed up deforestation in the Amazon where the reservations are considered effective means of preserving the forest.

Indigenous leaders meeting in the Xingu reservation last week issued a rallying call to protect the Amazon rainforest and its indigenous people from the "genocide, ethnocide and ecocide" they accuse Bolsonaro of planning. (Reporting by Anthony Boadle)