The ability to control fire changed the game for early humans, and scientists suggest they may have just gained insight into how the process came about. In a new study in the Journal of Evolution, researchers watched how monkeys behaved after grass fires—and how the primates seemed to realize the benefits, reports the Smithsonian. The researchers kept an eye on vervet monkeys when staffers set controlled fires at a South African nature reserve. By comparing distress calls before and after the fires, the researchers found that the monkeys seemed to feel safer after the blazes as they entered the burnt areas. The best guess is that this is because the fires made it harder for predators to lurk in lush vegetation. In fact, the fires made it possible for the monkeys to venture into new territory.
"Burning that grass was like turning this key and it opened up an entirely new area to them,” says lead researcher Nicole Herzog of the University of Denver. A researcher not involved with the study praised it as the best possible way to understand how our ancestors' thinking about fire might have evolved. As the study puts it, "these results provide foundations for examining hypotheses about the use of fire-altered landscapes among extinct hominins." So when did the first humans get the big idea? That's a little murky, author Andrew C. Scott writes in a previously published article in Time. The first known instances of the use of controlled fire go back about 1.5 million years, but he writes that regular, controlled use of fire likely didn't get underway until about 7,000 years ago. (Read more discoveries stories.)