While some animals have been spotted using tools, none do so with such aplomb as humans, which is probably in some part due to the fact we’ve been doing it for so long. While early examples such as flint axes might not look so impressive next to a smartphone, their creation at the time was quite astonishing. Now, a new analysis of some 300,000-year-old stone tools has revealed how even these early bits of kit were engineered with some ingenuity. The study, published in the journal Nature Human Behavior, found that hominins in the Levantine region used controlled fire to shape tools.

Previous research had revealed that flint tool production was happening among handy early hominins in the Levant during the Late Lower Palaeolithic (420,000 to 200,000 years ago), some of which even had evidence of exposure to fire. But little was understood as to whether this fire treatment was the effort of an artisan or simply an accident.

The researchers of this study looked to the Qesem Cave in central Israel, a key Levantine site during the Late Lower Palaeolithic era that has proved itself to play host to a significant collection of ancient artifacts. Here it was found that the use of fire to craft blades was both extensive and habitual among the early humans that inhabited the cave.

Aviad Agam, Filipe Natalio, and colleagues examined two types of flint tools that showed evidence of fire exposure. Using a combination of spectroscopy and machine learning, they were able to establish the approximate temperatures at which both pieces were burned to give them their texture and shape. Their findings revealed that blades were heated to a lower temperature of 259°C (500°F) than flakes at 413°C (775°F), while pot lids were heated to a temperature that exceeded both at 447°C (837°F).

Inspired by the world of their very early ancestors, they tried their hand at flame-powered tool production and discovered that controlling the temperature of flint has a big impact on the success of blade production. They conclude that their research shows that Levantine hominins were a dab hand at tool making, spurred on by their unique (at the time) concept of temperature control to enhance the production of flint tools.