South African Cave Find Pushes Human Fire Use Back Nearly 800,000 Years

New research from Wonderwerk Cave in South Africa suggests that human ancestors may have used fire far earlier than scientists had thought. The study, published in PLOS One, identifies burned mammal bones inside the cave that date to as much as 1.79 million years ago, far older than earlier evidence from the same site, which dated to about 1 million years ago and included burned bone fragments, plant ash and charred tools.

The bones were found inside fossilized owl pellets, compact masses of fur, bone and other animal remains left behind by birds of prey. Many of the tiny bones showed clear burn marks, leading the researchers to conclude that Homo erectus repeatedly brought fire deep into the cave and likely used dried owl pellets as tinder to keep flames going.

The team used a new non-destructive method to test whether the bones had really been burned. One technique examined how the material absorbed infrared light, but since it cannot reliably detect burning below about 536 degrees Celsius, they combined it with intense blue light and a special optical filter. Burned bones glowed bright red, while unburned ones did not glow at all, helping distinguish fire damage from chemical changes caused by millions of years of fossilization.

Researchers say the fire was probably taken from natural blazes outside and carried into the cave. Because the same pattern appears in different soil layers separated by tens of thousands of years, the evidence points to repeated use, not a one-time accident. The find does not prove that early humans regularly cooked food or knew how to create fire from scratch, but it strengthens the case that they could transport, preserve and maintain fire much earlier than previously believed.