Tigers and their prey: predicting carnivore densities from prey abundance

Using camera-trap density estimates of tigers alongside line-transect surveys of ungulate prey across many Asian sites, Karanth and colleagues tested whether predator density is governed by prey availability. They found a strong, predictable relationship: tiger densities scale closely with the biomass and density of large ungulate prey, implying that prey depletion, not just direct poaching, limits tiger numbers. The analysis integrated rigorous detection-corrected estimates for both predator and prey, demonstrating how camera-trap demography feeds into broader ecological theory. The result has major conservation implications, arguing that protecting and recovering prey populations is essential to sustaining viable tiger densities. It remains a landmark example of using camera-trap-derived abundance to answer a fundamental question about carnivore carrying capacity.