Herders (IMAGE) Saint Louis University Caption Herders move goats through the Engaruka Basin in northern Tanzania's Rift Valley. Ancient DNA shows that this way of life spread to East Africa through multiple population movements. Credit Katherine Grillo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.