Being able to master fire is like opening a path to a new world for ancient humans. Fire allows humans to get more nutrients through cooking, making the usually dark times without light more beneficial, thus surviving migration to colder climates.
How and when the taming of fire by early humans occurred, previously no one knew for sure. But evidence in the form of pieces of burning material, suggests that the taming of fire by humans may have started 1.5 million years ago.
Scientists are using artificial intelligence (AI) to detect hidden clues to a bonfire from a Lower Paleolithic site in Israel, which dates back about 1 million years.
Identifying a fire at an archaeological site usually relies on visual clues such as reddening of the ground, discoloration, warping, cracking and shrinking of the material.
In the new study, the researchers used a spectroscopic meter that can detect tiny chemical changes analyzed by a deep learning algorithm, which can estimate the exposure of rocks and fossils to heat.
Archaeologist Zane Stepka of the Kimmel Center for Archaeological Science in Israel and his colleagues used this spectroscopy on stone artifacts from a site in Israel, dated between 1.0 and 0.8 million years ago.
Quoted from Science Alert, Friday (17/6/2022) the artifact was found next to animal fossils in yellow-gray sand on top of red clay. There is no clear visual indication of the use of fire at this location.
However, the AI thermometer revealed subtle chemical signatures, showing that a number of stone tools and pieces of ivory had been heated to a wide range of temperatures, some even greater than 400 degrees Celsius. This indicates that they have made contact with fire.
But the researchers also caution that they cannot completely rule out the existence of forest fires because they are located in open areas. However, the grouping of tools and bones shows that early hominins (ancient humans) actually controlled and utilized fire.
Previously, it was thought that hominins' use of fire before about 150,000 years ago was simply opportunistic, as the Australian raptors deliberately spread fire to help dislodge prey. But if these fires are indeed confined to campsites, the findings suggest otherwise.
Only a handful of archaeological sites display signs of early human artifacts alongside evidence of fire, and this adds weight to the idea that our ancestors already made use of this powerful technology at that time.
The researchers said further use of this new research technique could help us reveal more about when and how humans mastered fire.
"Reexamining artifacts excavated from other Lower Paleolithic sites, including those in the Levant, has the potential to broaden our spatiotemporal understanding of the relationship between early hominins and fire," the team said.