The term "forage" means to wander in search of food. Every animal has a particular method of locating food, whether they smell it, find it by sight, or detect it by chemical means. Animals seek out food both individually and in groups.

Collecting food as efficiently as possible allows a species to propagate its genes more effectively. The optimal foraging theory, developed by Robert H. MacArthur and E. R. Pianka, states that food gatherers that do a better job of increasing the benefits and of decreasing the costs of foraging should procreate more effectively than those whose feeding activities yield lower net benefits. Foraging decisions are, in effect, cost-benefit problems that animals have to solve.

Food, whether animal or vegetable, provides stimuli that predators can detect. Waste products of animals give off olfactory signals that help predators locate their next meal. For example, when dung-eating beetles...