How Burn Injuries May Have Shaped Human Evolution, and Set Us Apart From Other Primates

Fire transformed human society in obvious ways. Less obvious is the possibility that living alongside flame also shaped human evolution. Over generations, recurring burn injuries may have influenced how our bodies repair tissue and resist infection.

A study published in BioEssays suggests that repeated exposure to burns acted as a selective pressure, favoring genetic adaptations that distinguish humans from other primates. By comparing primate genomes, researchers identified genes involved in tissue repair and immune regulation that evolved unusually quickly in humans. The findings point to an evolutionary force rooted not simply in fire itself, but in surviving its consequences.

“What makes this theory of burn selection so exciting to an evolutionary biologist is that it presents a new form of natural selection — one, moreover, that depends on culture. It is part of the story of what makes us human, and a part that we really did not have any inkling of before,” said co-author Armand Leroi in a press release.

Read More: Over 400,000-Year-Old Evidence of Fire-Making Unearthed — Thousands of Years Earlier Than Once Thought

How Burn Injuries Became a Form of Natural Selection

Burns do more than damage surface tissue. When skin is compromised, the body loses its primary defense against infection. Before modern medicine, even moderate injuries could become life-threatening if bacteria spread unchecked.

Thermal injuries can also damage large areas at once, increasing both fluid loss and infection risk. Under those conditions, speed mattered. Rapid tissue closure and a strong early immune response would have improved survival odds. Small physiological advantages, repeated across generations, could gradually reshape how the body reacts to injury.

“Our research suggests that natural selection favoured traits that improved survival after smaller, more frequent burn injuries,” said lead author Joshua Cuddihy.

Unlike environmental pressures such as climate or diet, this selective force emerged from a behavior that humans created and sustained themselves. The researchers argue that it was not fire alone, but the biological response to injury, that became the evolutionary variable.

Evidence That Burns Shaped Human Evolution

To test the idea, the team examined comparative genetic data across primates, searching for evolutionary signals in injury-response pathways.

Several genes involved in inflammation control, cell regeneration, and infection defense show evidence of change in the human lineage. These systems coordinate how damaged tissue is stabilized and protected.

The results do not suggest that burns drove human evolution as a whole. Rather, they indicate that repeated exposure to heat may have subtly shaped specific biological systems over time. Even modest survival advantages, compounded across thousands of generations, can leave a detectable imprint in the genome.

The Evolutionary Trade-Off of Burns

Traits that help the body survive everyday injuries can backfire in more extreme cases. Severe burns set off powerful immune reactions and strain the entire body. The same responses that once helped prevent infection can spiral out of control when damage is widespread.

“Those same adaptations may have come with evolutionary trade-offs, helping to explain why humans remain particularly vulnerable to the complications of severe burns,” Cuddihy said.

From an evolutionary standpoint, natural selection optimizes for what happens most often, not worst-case scenarios. Minor burns likely occurred far more frequently than catastrophic injuries. Traits that promoted defense would have been beneficial overall, even if they now contribute to scarring or organ dysfunction in modern burn units.

The researchers hope future work will explore how variation in these genes influences recovery today. Understanding the evolutionary roots of burn response, they suggest, may help explain why healing outcomes differ between patients — and why translating burn research from animal models to humans has often proved difficult.

Mastering fire reshaped human history. This study suggests it may also have shaped the biological systems that allow us to survive injury, leaving a genetic signature written in the way our bodies heal.

Read More: Early Humans May Have Used Fires to Smoke Meat One Million Years Ago

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from a recent study published in the BioEssays: Burn Selection: How Fire Injury Shaped Human Evolution