The San, a hunter-gatherer tribe, are the first and oldest inhabitants of Southern Africa. The evidence of the existence of the San thousands of years ago, can be found across Southern Africa with stone tools and rock art paintings found across the region.
The San, much like the Aboriginal people in Australia and the American Indians were once large in number, but due to many factors such as colonization and spread of disease contracted by foreign settlers, the population of San decreased dramatically. The San were a migratory tribe constantly travelling from place to place in search of food and water.
They were called "San" by pastoralist Khoikhoi rivals, meaning "foragers" but the San themselves prefer to be called by their names of their individual nations. They travel in small groups made up of about 25 men, women and children.
When the European settlers arrived, the San peacefully co-existed with two other tribes namely, the pastoralists (Khoikhoi) and the farmers (BaNtu). The San intermarried with the Nguni speakers (the Zulu, Xhosa, Swazi and Ndebele), and the 'clicks' that are found in the language of the San were incorporated in the Nguni languages.
After disagreements arose between the San and the stronger tribes and also the European settlers, the San were outnumbered and also lacked the weapons to defend themselves. They prefered fighting to the death than being captured and being forced into slavery.
The San's migratory way of life was destroyed by colonialism, restricting their movement across the region. Their supply of food was also affected by trophy hunters destroying the vast herds of game.
Source 1 - wikipedia
Source 2 - krugerpark.co.za