A hunter-gatherer or forager society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species.

Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were hunter-gatherers until around 10,000 years ago. Following the invention of agriculture hunter-gatherers have been displaced by farming or pastoralist groups in most parts of the world. Only a few contemporary societies are classified as hunter-gatherers, and many supplement, sometimes extensively, their foraging activity with farming and/or keeping animals.

The earliest humans probably lived primarily on scavenging, not actual hunting. Early humans in the Lower Paleolithic lived in mixed habitats which allowed them to collect seafood, eggs, nuts, and fruits besides scavenging. Rather than killing large animals themselves for meat, they used carcasses of large animals killed by other predators or carcasses from animals that died by natural causes.

Jared Mason Diamond (born September 10, 1937) is an American scientist and author best known for his popular science books The Third Chimpanzee, Guns, Germs, and Steel, and Collapse: How Societies Choose to Fail or Succeed. Originally trained in physiology, Diamond's work is known for drawing from a variety of fields, and he is currently Professor of Geography at the University of California, Los Angeles.

Diamond was born in Boston, Massachusetts, to a Bessarabian Jewish family. His father Louis K. Diamond was a physician and his mother Flora Kaplan a teacher, musician, and linguist. He attended the Roxbury Latin School and earned an A.B. from Harvard College in 1958 and a Ph.D. in physiology and membrane biophysics from the University of Cambridge in 1961.

After graduating from Cambridge, Diamond returned to Harvard as a Junior Fellow until 1965, and, in 1968, became Professor of Physiology at UCLA Medical School. While in his twenties, he developed a second, parallel, career in ornithology and ecology, specialising in New Guinea and nearby islands. Then in his fifties, Diamond developed a third career in environmental history and became Professor of Geography at UCLA, his current position. He was awarded the National Medal of Science in 1999 and an honorary doctorate by Westfield State University in 2009.