- Partial seasonal migration is ubiquitous in many species. We documented this phenomenon in plains zebra (Equus burchelli) in Etosha National Park, Namibia (ENP), and provided a cost–benefit analysis as it relates to the spatial distribution of water, vegetation, and endemic anthrax. This analysis draws upon two years of ENP zebra movement data that reveal two sub‐populations: migrators and non‐migrators. Migrators are shown to be behaviorally dominant in the way they utilize space and use water holes. We raise the possibility that the co‐existence of these two groups reflects an evolutionary process, and the size of each group maintains evolutionary equilibrium.