Why are carnivores found at lower population densities than herbivores?

Carnivores are found at lower population densities than herbivores primarily because they depend on meat, which necessitates that there be fewer predators than the prey animals they consume. This relationship is governed by the flow of energy through food chains.1

As energy moves from one trophic level to the next, a significant amount is lost; on average, only about 10 percent of energy is transferred between levels. Because most energy is concentrated in plants at the base of the pyramid, there is progressively less energy available to support organisms at higher levels. Consequently, the ecosystem’s carrying capacity for predators is strictly limited by the available biomass of their prey.21

Additionally, many carnivores maintain territories, which further restricts their population density. While carnivores possess high assimilation efficiencies—meaning they are very effective at converting ingested food into energy—the fundamental constraints of energy transfer ensure that their populations remain significantly smaller than those of the herbivores they rely upon.12