Historian Ian Morris states that for nearly 99% of human history, there were no governments to wage war. Morris, a historian at Stanford University and author of "War! What Is It Good For? Conflict and the Progress of Civilization from Primates to Robots," said researchers typically define war as violence organized by a government or collective violence resulting in a minimum number of fatalities.

"If war means a fight between two governments, then yes, there have been peaceful periods because for nearly 99% of human history, there were no governments," Morris said. When asked whether people have ever lived without violence, Morris said, "The answer is pretty clearly no — people have always fought and killed each other." Prehistoric societies rarely had formal governments, and hunter-gatherer bands usually consisted of only a few dozen members. David Christian, a historian and professor emeritus at Macquarie University, said that given the small size of these communities, it is unclear if violence could be equated with war. "For much of human history communities were so small that it is not clear if we can equate violence with war," Christian said.

A 2022 review of studies concluded that war was rare or nonexistent in early human history when people lived as nomadic hunter-gatherers. Researchers examining ancient human bones for war injuries, such as unhealed wounds from stabbing, slicing, and blunt force trauma in mass graves, found little evidence of such injuries before 8000 B.C. War injuries appeared widely in skeletal records after humans began transitioning from nomadic life to permanent settlements around 8000 B.C.

Researchers in Kenya found 27 skeletons dating to 10,000 years ago at the archaeological site of Nataruk showing signs of violent death. Some anthropologists interpret these skeletons as evidence of intergroup violence among early hunter-gatherers. Additionally, archaeologists unearthed 13,000-year-old remains bearing signs of intergroup attacks at Jebel Sahaba, a prehistoric cemetery in Sudan.