The evolutionary story of the warthog is intertwined with which major environmental change in Africa?

The expansion and drying of African grasslands

The distinct morphology and specialized adaptations seen in the warthog are direct consequences of adapting to the changing landscape of Africa over vast geological timescales. The evolutionary narrative that sculpted traits like their grazing habits and specialized dentition is closely connected to the process of the expansion and subsequent drying of the African grasslands. As savannas spread, the availability of mixed forage decreased, favoring animals that could efficiently process the tough, abrasive grasses that flourished in these drier conditions. This environmental context provided the necessary selective pressure that drove the warthog toward its current extreme specialization, distinguishing it from more generalized, older suid lineages.