New evidence from South Africa’s Wonderwerk Cave suggests early humans were using fire inside caves far earlier than many archaeologists once believed. A study published in PLOS One reports signs of repeated fire use in deposits dating between about 1.07 million and 1.79 million years ago, making the site one of the oldest known records of hominin fire use.
Early humans used fire in Wonderwerk Cave up to 1.8 million years ago. Credit: Archaeology News Online Magazine
Wonderwerk Cave has attracted scientific attention for decades because of its long record of human occupation. Earlier research identified traces of burning in layers dating to around one million years ago. The new study examined deeper deposits and found evidence pointing to an even older history of fire use.
Researchers analyzed 161 fossilized bones from small mammals recovered from two Early Pleistocene layers known as Strata 10 and 11. Many of these animals likely entered the cave through barn owl activity. Owls often left pellets on the cave floor, creating deposits that accumulated over thousands of years. Some of those remains later came into contact with fire.
To determine whether the bones had been heated, scientists combined two separate techniques. One involved Fourier Transform Infrared Spectroscopy, known as FTIR, which detects structural changes in bone caused by high temperatures. The second relied on bone luminescence. Under blue light and special filters, heated bones produce a reddish glow, while unheated bones do not.
The team tested this optical method using modern bones exposed to controlled heating conditions. Researchers also compared results with archaeological material from a Bronze Age site in Spain. The luminescence findings matched the FTIR results, supporting the reliability of the approach.
Analysis of the Wonderwerk Cave fossils revealed clear signs of burning in both archaeological layers. Every white and gray fossil bone tested from the older Stratum 11 showed evidence of heating. Results from two independent methods pointed to the same conclusion.
Wonderwerk Cave, South Africa. Excavation areas showing stalagmite landmark, grid layout, and sampled strata. Sections highlight lithostratigraphic units, archaeological layers, paleomagnetic zones, and evidence of burning in multiple deposits. Credit: Marin-Monfort et al., PloS One (2026)
The location of the burnt material plays a key role in the study. The fossils came from deposits at least 30 meters inside the cave. Natural grass or bushfires would have struggled to reach such depths. Researchers argue that this distance makes accidental burning from wildfires unlikely.
The pattern of burnt remains adds further support. Burnt bones appeared in distinct clusters rather than being spread evenly throughout the excavation area. Such distributions suggest repeated burning events occurred in specific parts of the cave over long periods.
The fossils were found alongside Acheulean stone tools and larger animal remains. This association links the evidence with hominin activity. According to the research team, the most likely occupants responsible for bringing fire into the cave were early Homo erectus populations.
The study does not suggest these hominins produced fire themselves. Researchers propose they collected fire from natural sources and kept it burning for some time after transport. Even so, carrying fire into a cave required planning and control beyond simple exposure to natural flames.
Fire offered several advantages. It provided warmth, protection from predators, and light after sunset. Later in human history, cooking changed diets and increased access to nutrients from food. Because of its importance in human evolution, the timing of the earliest controlled fire use remains one of archaeology’s most debated topics.
The findings from Wonderwerk Cave strengthen evidence that hominins were managing fire much earlier than once thought. The study also introduces a fast, non-destructive technique for identifying ancient burning. Future research at other archaeological sites could help refine the timeline of early fire use across Africa and beyond.
Publication: Marin-Monfort, M. D., Shaw, C. L., Natalio, F., Grossman, L., Andrews, P., Campos, J., … Fernández-Jalvo, Y. (2026). New evidence for Early Pleistocene use of fire at Wonderwerk Cave (South Africa). PloS One, 21(6), e0347480. doi:10.1371/journal.pone.0347480