At the rugged edge of the Cape Peninsula, where the turbulent South Atlantic collides with the icy, nutrient-rich currents sweeping upward from the Antarctic, an extraordinary behavioral transition is unfolding. Here, a unique population of Chacma baboons ( Papio ursinus ) has abandoned the traditional montane foraging of their inland relatives to exploit the rocky intertidal reefs. This coastal fringe represents the absolute southernmost ecological boundary for any wild, non-human primate. Driven by the freezing waters of the Benguela Upwelling System—an oceanographic current system directly fed by the sub-Antarctic Circumpolar Current—this marine environment presents both a perilous hazard and an unparalleled evolutionary opportunity for these highly adaptable primates. The Southernmost Frontier of Primatology While primatologists historically focused on tropical rain forests and equatorial savannas, recent long-term population studies have turned their a...