When early humans discovered how to purposefully create fire and make the most of it for their survival, it was a feat comparable to modern day milestones of sending men to the moon, but while the mastery of fire is hailed as among the most crucial developments in human history and evolution, researchers are not certain when this happened.

Some anthropologists believe that early humans started to exploit fire as early as 1.5 million years ago, but much of the evidence supporting this claim such as the heated clays and charcoal fragments is disputed because they can be attributed to natural bush fires. Many experts also think that the early uses of fire were opportunistic, meaning early humans used natural bush fires instead of starting the fire themselves.

A group of archeologists studying artifacts from an ancient cave, however, claims to have figured out when humans learned to master fire. For their study published in the journal Science on Oct. 19, Ron Shimelmitz, from the Zinman Institute of Archaeology of the University of Haifa in Israel, and colleagues examined artifact, most of which were flint tools and debris excavated from Israel's Tabun Cave.

The archeological site, which was declared as having universal value by UNESCO two years ago, documents half a million years of human history and provided the researchers with the opportunity to study how the use of fire evolved in the cave.

By examining the cave's sediment layers, the researchers found that most of the flints were not burned in layers that were older than 350,000 years old. Burned-up flints, however, started to show up more regularly after this with most of the flints characterized by cracking, red or black coloration, and small round depressions where fragments called pot lids flaked off the stone, indicating exposure to fire.

The researchers said that since wildfires rarely occur in caves, ancestral humans likely had something to do with the burning of the flints. They also said that the increase in the frequency of burned flints indicate the time when humans learned how to control fire.

Shimelmitz and colleagues said that while fire had been in use for a long time, it took a while before humans learned how to control and start it with the study indicating that habitual use of fire in Israel's Tabun Cave started just between 350,000-320,000 years ago.

"While hominins may have used fire occasionally, perhaps opportunistically, for some million years, we argue here that it only became a consistent element in behavioral adaptations during the second part of the Middle Pleistocene," the researchers wrote.

ⓒ 2018 TECHTIMES.com All rights reserved. Do not reproduce without permission.