Hamar women dance before a bull jumping ceremony in Ethiopia's southern Omo Valley region near Turmi on September 19, 2016. The Hamar are a Nilotic ethnic group in Ethiopia. The construction of the Gibe III dam, the third largest hydroelectric plant in Africa, and large areas of very “thirsty” cotton and sugar plantations and factories along the Omo river are impacting heavily on the lives of tribes living in the Omo Valley who depend on the river for their survival and way of life. (Photo by Carl De Souza/AFP Photo)

An indigenous girl carries a monkey inside her house in their village at Xingu national park in Mato Grosso, Brazil, October 2, 2015. The Kamayura tribe consists of around 300 people, and is one of the 16 ethnic groups living in the indigenous Xingu national park. (Photo by Paulo Whitaker/Reuters)

Cows belonging to Samburu tribesmen walk around the carcass of an elephant killed by armed cattle herders in Mugui Conservancy, Kenya February 11, 2017. Kenya has declared the ongoing drought affecting many parts of the country a national disaster, calling for aid to counter the situation which is posing a major risk to people, livestock and wildlife. (Photo by Goran Tomasevic/Reuters)

Young Turkana tribeswomen sing in a village near Baragoy, Kenya August 6, 2017. Kenyans are due to go to the polls on Aug. 8. to vote in presidential elections after a tightly-fought race between President Uhuru Kenyatta and main opposition leader Raila Odinga. (Photo by Goran Tomasevic/Reuters)

Camel herders scoop up water in plastic buckets from one of the few watering holes in the area, to water their animals near the drought-affected village of Bandarero, near Moyale town on the Ethiopian border, in northern Kenya, Friday, March 3, 2017. The U.N. humanitarian chief, Stephen O'Brien, toured Bandarero village on Friday and called on the international community to act to “avert the very worst of the effects of drought and to avert a famine to make sure we don't go from what is deep suffering to a catastrophe”. (Photo by Ben Curtis/AP Photo)

A policeman stands next to supporters of Kenyan President Uhuru Kenyatta lying unconscious after being beaten by police when they tried to storm through gates to get in during Kenyatta's inauguration ceremony at Kasarani stadium in Nairobi, Kenya Tuesday, November 28, 2017. Kenyatta is being sworn in on Tuesday, ending a months-long election drama that saw the first vote nullified by the country's top court and the second boycotted by the opposition. (Photo by Ben Curtis/AP Photo)

A motorcycle carrying protesters holding a placard using the acronym of the national electoral commission, drives ahead of demonstrators on foot calling for the disbandment of the commission over allegations of bias and corruption, in downtown Nairobi, Kenya Monday, June 6, 2016. (Photo by Ben Curtis/AP Photo)