Brandi L. MacDonald (IMAGE) University of Missouri-Columbia Caption University of Missouri scientist Brandi L. MacDonald collects ochre and clay raw materials in Eswatini, southern Africa, for the study. Credit Photo courtesy Brandi L. MacDonald, Gregor Bader and Jörg Linstädter Usage Restrictions For media use License Original 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.