Populations of rsquo & the world;s carnivores today occupy fractions of the ranges and are declining. Theory predicts that when apex predators disappear herbivores become fearful, occupy new habitats, and then change those habitats by eating food plants. Yet support for this forecast has been hard to get large-mammal systems. Following the extirpation of leopards and African wild dogs from Mozambique’s Gorongosa National Park, forest-dwelling antelopes [bushbuck (Tragelaphus sylvaticus)] enlarged into treeless floodplains, where they absorbed book diets and suppressed a common food plant [waterwort (Bergia mossambicensis)]. We demonstrate that this behaviour was reversible, by simulating predation risk. Thus, by allowing rapid differentiation of prey behavior, whereas predator extinction disrupted a cascade, that cascade may be equally as quickly reestablished by carnivore restoration.