Ancient Humans Were Carrying Fire Into Caves 1.8 Million Years Ago

Ancient Humans Mastered Fire Far Earlier Than We Thought

Groundbreaking new research has revealed that early human ancestors were actively using fire inside South Africa's Wonderwerk Cave as far back as 1.79 million years ago — pushing the known timeline of human fire use further into the past than ever before.

The discovery, published in the journal PLOS One, centers on burned animal bones recovered deep within the cave. Because the bones were found roughly 30 meters inside the cave — well beyond any area that natural wildfires could have reached — researchers concluded that fire was deliberately transported and maintained by early hominins, not ignited by chance.

What the Evidence Reveals

Scientists from an international collaboration spanning Spain, Argentina, Canada, the United States, South Africa, Portugal, and Israel worked alongside Dr. Liora Kolska Horwitz of the Hebrew University of Jerusalem and Prof. Michael Chazan of the University of Toronto to conduct the study. Their work draws on archaeology, paleontology, geology, and other disciplines to explore one of the most pivotal developments in human evolution.

The team identified repeated traces of fire use within archaeological deposits dating between 1.07 and 1.79 million years ago. These findings build on an earlier 2012 report from the same site, which documented fire evidence dating back approximately one million years — at the time considered the oldest confirmed instance of intentional fire use on Earth. The new analysis extends that record by hundreds of thousands of years.

The burned remains were found within an archaeological layer connected to early Acheulean stone tools, a technology typically associated with Homo erectus. Crucially, the absence of guano deposits in the same layer eliminated spontaneous combustion as a possible explanation for the burning.

A New Tool for Detecting Ancient Fire

How the Luminescence Technique Works

A key highlight of the study is the introduction of an innovative, non-destructive method for identifying burned fossil bones. When certain wavelengths of light are directed at bones that have undergone intense heat exposure, those bones emit a distinctive glow — a phenomenon rooted in their light-emitting, or luminescence, properties.

Researchers combined this portable luminescence technique with established chemical analyses to identify burning evidence with a high degree of confidence. Because the method is non-invasive, it can be applied to large fossil collections without causing any damage to the specimens.

To validate the approach, the team examined hundreds of tiny bones from owl pellets — the compressed masses of fur and bone that owls regurgitate after meals — that had accumulated naturally on the cave floor over thousands of years. These remains provided an independent, non-human record of environmental events within the cave, helping researchers distinguish natural burning from human-associated fire.

Carrying Fire, Not Creating It

Importantly, the evidence does not suggest that these early humans had mastered the ability to create fire on demand. Rather, the findings point to a sophisticated but simpler behavior: collecting fire from natural sources — such as wildfires ignited by lightning strikes across the African savanna — and carefully transporting it back to the cave.

Once inside, these ancient humans appear to have kept the fire alive over extended periods before it eventually died out. Researchers also proposed that owl pellets found within the cave may have served as a convenient fuel source, which would help explain why the small rodent bones embedded in those pellets also show signs of heat exposure.

A Defining Moment in Human Behavioral Evolution

The ability to deliberately carry and sustain fire represents a significant cognitive and behavioral leap. Fire provided warmth against cold nights, protection from predators, illumination after dark, and — in time — the capacity to cook food, which many scientists believe played a crucial role in shaping the development of the human brain.

"These discoveries show that early humans were not simply passive observers of natural fires," said Dr. Kolska Horwitz. "They were actively engaging with fire and incorporating it into their lives."

Her colleague emphasized the broader significance of the detection method itself: "Evidence of fire from such ancient sites is often subtle and difficult to detect. Our study provides new tools for identifying traces of ancient burning and reveals that fire was repeatedly present deep inside Wonderwerk Cave."

Implications for Future Archaeological Research

Beyond rewriting the timeline of fire use, the study equips archaeologists worldwide with a powerful new technique for investigating prehistoric fire at other ancient sites. As researchers apply this luminescence-based method across archaeological digs around the globe, it holds the potential to answer some of the most enduring questions about when and how humanity first began harnessing one of nature's most transformative forces.