For most of human history people were trying to survive against violent predators and similar threats, and the average lifespan was 40 years.

Judge against historical and demographic research on human life expectancy and causes of death. True: the evidence shows that for most of human history average life expectancy at birth was about 40 years, and that predators and violence were a major survival challenge. Mostly true: the lifespan figure is roughly right (about 30–40 at birth) and the predator point is a minor overstatement. Mixed: one part holds and the other does not. Mostly false: the claim distorts something true, e.g. low life expectancy at birth (often about 25–35, driven by infant mortality) presented as people typically dying at 40, or predators presented as the main threat when disease and starvation dominated. False: the evidence contradicts both parts outright.

Set before the research began.

1. E1 Demographic perspectives on the rise of longevity - PMC PubMed Central (PNAS review, Bergeron-Boucher et al.) · 10 February 2021

   “Various estimates indicate a life expectancy at birth of less than 40 y for these populations (41).”

2. E2 Demographic perspectives on the rise of longevity - PMC PubMed Central (PNAS review, Bergeron-Boucher et al.) · 10 February 2021

   “Hence, it can be concluded that human life expectancy before 1840 generally fell below 40, and in situations of famine, epidemic, or war, the value could be much lower.”

3. E3 Misperceiving Life Expectancy in the Deep Past Sapiens (republished from The Conversation) · 14 September 2022

   “What some people don’t realize is that low life expectancy at birth for any population usually reflects very high rates of infant mortality.”

4. E4 The prehistoric psychopath - Works in Progress Magazine Works in Progress · 13 March 2025

   “Analysis indicates that prehistoric hunter gatherers were considerably less violent than is commonly believed.”

E1 and E2 show life expectancy at birth was generally below 40 and E3 links low figures to infant mortality, but no evidence addresses predators or the relative weight of disease and starvation; E4 concerns violence between humans only. The evidence therefore does not settle the predator part of the claim under the criteria.