The Masai are one of the smaller tribes in East Africa, numbering approximately 350,000 people who occupy the Rift Valley in Kenya and Central Tanzania, an area the size of France. Within the Masai speaking people are independant units known as il oshon, each with its own identity, territory, style of dress etc. The Masai culture is based on age groups with each generation in turn handing over its junior members. Members of each age set share the major transitions in life, marked by colourful ceremonies. Most of their working day is taken up by tending to their cattle which is their main source of income. Many of the tribesmen have also diversified by turning their hand to carving wooden ornaments and trinkets for the tourist trade.