According to a new study published in the journal Nature Human BehaviorThe stone tools found at the Qesem cave in central Israel are important evidence that early human ancestors could control the temperature of the fire and this was a birth skill. important inventory.
The low heating of flint allows for better control of flaking during baking. When this threshold was reached, early humans were able to use tools made of fire for many different purposes. The discovery was made by archaeologist Filipe Natalio from the Weizmann Institute of Science in Israel.
Silje Evjenth Bentsen, an anthropologist at Bergen University who is not involved in the new study, says the use of fire by human ancestors is currently a hot topic in archaeological research.
Bentsen shared: “Personally, I think that human ancestors could not last long in the cold Eurasian climate without hot food and warm fire. But some researchers still argue that the use of fire is controlled. If human ancestors lived in the Qesem cave and used fire 300,000 years ago for the purpose of tool making then that is a sign of better use of fire. it can also help us understand how and when our ancestors controlled fire and used it randomly in everyday life. “
The technique of making tools with fire has been known to archaeologists for a long time. Previous research showed this method was used in the Levant 420,000 to 200,000 years ago. Burnt flint pieces suggest this approach. It is not clear though, this is just a coincidence or that humans actually control their flames for the purpose of making stone tools.
Douze says the use of fire to make wooden spears dates back about 400,000 years, but “heat smelting” probably requires a higher engineering effort, especially when flint is very sensitive to sudden temperature changes. If the heating is not proficient, the stone will break immediately and become unusable.
As evidence of this discovery, Natalio and his colleagues analyzed two types of igneous tools found in the Qesem cave, which is known to have remains of ancient fires. They use spectroscopic chemistry analysis and machine learning to estimate the temperature when flint is heated. The results showed that the tool was heated to 259 degrees Celsius, lower than the slabs, which were already 413 degrees Celsius. Spears found in the same location were even hotter, with temperatures up to 447 degrees Celsius.
From left to right: a pot lid, remaining debris, blade
Douze said: “This difference further confirms the fact that humans intentionally heat the stone. It is still necessary to define how the ancients heated the blocks in situ and how the stone’s temperature was managed.”
It is possible that they used the sand below where the stones were heated or used multiple heating systems so that the stone could reach the required temperature.
Bentsen says: “The use of machine learning is an innovative and important method of information in future studies. Flint samples are fired in a temperature controlled furnace environment. we have a good basis for measuring the changes caused by heat in flint “.
However, this prehistoric technique would require quite a bit of work, as it would require ancient people to collect objects to burn and hot rock. Therefore, the authors hypothesize that the collection of burning materials is not only for the manufacture of stone tools, but also for everyday activities, such as cooking.
She said: “The ability to plan ahead and understand the various steps of a process is an important vital skill. This process requires many steps and careful planning, for example you need to know which rocks to use. heat, collect all the rocks and materials You must generate enough heat, not too hot, not too cold, and understand how long the fire should burn.After heating, the rocks must be carefully cooled. kidneys before use “.
The study concluded that human ancestors mastered the process of using fire to forge stone tools 300,000 years ago or even earlier. Obviously, evolution in the way of making tools has made it easier for people to obtain a food source for higher activities.