FACTBOX: Facts about Kenyan tribes

(Reuters) - Ethnic rivalries are a reality of life in Kenya, where President Mwai Kibaki's disputed re-election has triggered days of riots.

Here are some facts about its tribal communities:

* Kenya's 36 million people are split into more than 40 different ethnic groups, each with its own strong identity, a variety of cultural traditions, and separate tongues.

* The main groups are -- Kikuyu (22 percent); Luhya (14 percent); Luo (13 percent); Kalenjin (12 percent); Kamba (11 percent), according to government statistics.

* President Mwai Kibaki is a Kikuyu. His group comes mainly from the central highlands, wields strong economic power, and is solidly behind him for the election.

* Opposition leader Raila Odinga is a Luo, from western Kenya near Lake Victoria on the border with Uganda. Odinga's Nairobi constituency, Langata, includes one of Africa's largest slums where a large Luo population is fanatically behind him.

* Former President Daniel arap Moi comes from the Kalenjin group that has produced most of Kenya's famous long-distance runners.

* The Maasai, Kenya's best-known tribe and favourite on tourism posters, believe their god gave them all the cattle on earth and were entirely dependent on cattle alone for centuries. Many still live on just milk and fresh blood.

* Kenya is lauded internationally for remaining at peace since independence in 1963, while most of its neighbors in the region experienced war and chaos. But it is often criticised too for failing to tackle ingrained tribalism, compared with neighboring Tanzania, where founding President Julius Nyerere is credited with uniting the whole country against it.

* Ethnic flare-ups are common in Kenya, especially around elections. The worst incidents came in 1992 when some 1,500 died in tribally tinged land clashes in the Rift Valley region. Five years later, another 200 were killed, mainly in fighting in the resort town of Mombasa.

(Reporting by Helen Nyambura)