What is optimal foraging?

Optimal foraging is a theory that states an animal maximizes its net energy intake per unit of time spent foraging. Animals that engage in optimal foraging are favored by natural selection.

The theory of optimal foraging was first proposed by R. H. MacArthur and E. R. Pianka in 1966 to explain why animals restrict themselves to certain foods when there is more available. According to the theory, animals attempt to balance their food search between spending more energy looking for highly valued foods and spending less energy looking for more common foods. Factors such as the threat of predators may prevent an animal from following this strategy.