searching for wild food resources
Humans that forage are often called hunter-gatherers, who find and eat (wild) animals and plants without domestication of them (people who farm plants are not hunter-gatherers, as they have grown them themselves).
- Emlen J. M (1966), "The role of time and energy in food preference", The American Naturalist, 100: 611–617, doi:10.1086/282455
- Hughes, Roger N, ed. (1989), Behavioural mechanisms of food selection, London & New York, p. v, ISBN 0-387-51762-6
- MacArthur R.H. & Pianka E.R (1966), "On the optimal use of a patchy environment.", The American Naturalist, 100 (916): 603–9, doi:10.1086/282454, JSTOR 2459298