" In a fascinating study, Barrett (1999) demonstrated that children as young as three
years of age have a sophisticated cognitive understanding of predator-prey encounters. Children from both an industrialized culture and a traditional hunter-horticulturalist culture were
able to spontaneously describe the flow of events in a predator-prey encounter in an ecologically accurate way. Moreover, they understood that after a lion kills a prey, the prey is no longer alive, can no longer eat, and can no longer run and that the dead state is permanent.
This sophisticated understanding of death from encounters with predators appears to be developed by age three to four. "

― David M. Buss , Evolutionary Psychology: The New Science of the Mind