posted Ancient humans 'followed rains' BBC: July 21, 2006
Prehistoric humans roamed the world's largest desert for some 5,000 years, archaeologists have revealed.
Humid conditions prevailed until about 6,000 years ago, when the Sahara abruptly dried out. There was then a gradual exodus of people to the Nile Valley and other parts of the African continent.
The domestication of cattle was invented in the Sahara in the humid phase and was then slowly pushed over the rest of Africa.