Ancient Peruvian societies remained peaceful Despite extreme El Niño flooding

Archaeologists found that ancient societies in the Lambayeque Valley of Peru maintained low levels of violence even during periods of severe climate stress.

Researchers analyzed skeletal remains to see if the scarcity of resources caused by El Niño, a climate pattern that brings extreme weather, led to a rise in interpersonal conflict. The team examined the Lambayeque Valley Biohistory Project record, which includes skeletal data from 30 sites spanning more than 3,000 years.

They compared evidence of cranial trauma and accidental injuries against paleoclimate models of rainfall and water availability. While the Moche and Sicán cultures performed large-scale human sacrifices to appease the natural world during these crises, the researchers found that everyday violence remained exceptionally rare. The study shows that only a small fraction of the individuals sampled showed signs of violent trauma. This suggests that widespread social unraveling and violence are not inevitable reactions to climate change.

The researchers note that while these results reflect long-term trends, the valley's access to the sea or specific social structures might have helped the population manage resource scarcity without turning to internal conflict.