The Maasai are a Nilotic people of northern, central, and southern Kenya and northern Tanzania, whose ancestors migrated south from what is now South Sudan around the 15th century. Traditionally fully nomadic pastoralists, Maasai society is organized around age-sets that every man passes through over his lifetime, from warrior to elder.
Maasai men move through named age-sets over their lifetime; as moran (warriors), they train for years before initiation into elderhood, and their jumping dance, adumu, is a display of the height each dancer can leap from a standing position.