In South Africa, the Karoo region is rich in therapsid fossils, the ancestors of mammals that ruled the world long before the dinosaurs appeared. A team from the University of the Witwatersrand is searching for these fascinating rocks that hold the secrets of the extraordinary reptiles known as therapsids. Divided into six families, they vied for the crown of king of the Karoo… but only one would survive to give rise to our lineage.