Tigers and their prey: predicting carnivore densities from prey abundance

Karanth and colleagues combined rigorous camera-trap capture-recapture estimates of tiger density with line-transect estimates of ungulate density across Indian reserves to test whether prey biomass predicts tiger numbers. They found a strong positive relationship: tiger density rises with the abundance of large ungulate prey, and prey depletion, not habitat alone, is the proximate limit on tiger populations. The study provided the empirical foundation for prey-based tiger conservation, showing that protecting and recovering ungulate prey is the most direct lever for increasing tiger numbers. Its methods for jointly estimating predator and prey densities became standard, and its core finding underpins recovery targets across the tiger's range.