Fire was used to make tools by our early human ancestors some 300,000 years ago, an analysis of flint blades unearthed in a cave east of Tel Aviv has revealed.
Researchers from Israel studied stone blades, flakes and pot-lids from the Qesem cave — and discovered evidence that they had been exposed to controlled fires.
Exposing the flints to specific intensities of fire would have improved blade production, the team explained.
Previous studies identified fire-altered tools from the Late Lower Palaeolithic — 420–200,000 years ago — but it had been unclear if such had been heated intentionally.
Fire was used to make tools by our early human ancestors some 300,000 years ago, an analysis of flint blades (pictured) unearthed in a cave east of Tel Aviv has revealed
'The use of fire to treat raw materials was an important discovery made by early hominins,' said paper author and archaeologist Filipe Natalio of the Weizmann Institute of Science in Rehovot, Israel.
In their study, Dr Natalio and colleagues analysed the burned artefacts from the Qesem cave using a scanning technique called spectroscopy which uses beams of light to assess the temperatures to which the flints were heated.
Based on the presence of micro-cracks and colour changes, the team found that blades were warmed much less than flakes — 498°F (259°C), compared to 775°F (413°C), respectively. Pot lids from the same site reached a sizzling 837°F (447°C).
By replicating these conditions in a lab. experiment, the team were able to show that controlling the fire intensity in such a way improved the quality of the flint blades.
'Levantine hominins may have purposefully heated materials to different temperatures in order to enhance the production of tools,' said Dr Natalio.
The findings indicate that our ancestors in the Levant — what is today known as Israel, Lebanon, Egypt, Syria and Palestine — had control over fire hundreds of thousands of years ago.
Previously, it had been thought that the flint was exposed to different intensities of fire largely at random. Heat treatment is known to make flint shaping easier.
'These results are consistent with a differential behaviour for selective tool production that can be viewed as part of a plethora of innovative and adaptive behaviours of Levantine hominins around 300,000 years ago,' Dr Natalio said:
The Qesem cave — which lies in the rolling countryside east of Tel Aviv — was first discovered 20 years ago by road builders.
The site has provided a captivating glimpse into humanity's remote past — and is home to the world's first known fireplace.
The discovery of charred remnants of animal bones and flint tools once used for butchering meat paint a picture of families cooking and eating around the fire.
Researchers from Israel studied stone blades (pictured), flakes and pot-lids from the Qesem cave — and discovered evidence that they had been exposed to controlled fires
The findings add to evidence that the Levantine hominins of this time were a very sophisticated, clever people — whose toolmaking was advanced.
They were at the start of a new stage of human existence when people hunted deer skilfully, gathered firewood, made barbecues and ate well.
'Pyro-technology for the heat treatment of raw material' was one ancestors' many uses for fire, Dr Natalio explained.
'It permitted greater control over the knapping process, providing hominins with sets of tools with unique properties for improved adaptation and survival.'
'Our study of flint tools provides evidence consistent with hominins at the site heating flint to low temperatures specifically for improving blade production.'
Exposing the flints to specific intensities of fire would have improved blade