(JTA) — A fossil found in Israel indicates modern humans may have left Africa as much as 100,000 years earlier than previously thought.

Scientists say that an ancient upper jawbone and associated stone tools could also mean that Homo sapiens, modern humans, arose in Africa far earlier than fossils now show, according to a study published this week in the journal Science by Tel Aviv University anthropologist Israel Hershkovitz.

The results of Hershkovitz’s study may cause rethinking about how we evolved and interacted with now-extinct cousin species, such as Neanderthals, according to the Associated Press.

“When they start moving out of Africa and what geographical route they choose to do it are the two most important questions in recent human evolution,” Hershkovitz told AP.

The jawbone, complete with several well-preserved teeth, was dated to be somewhere between 177,000 and 194,000 years old.

Previously, the oldest fossils of modern humans found outside of Africa were somewhere from 90,000 to 120,000 years old, also in Israel. Given the range in both those estimates, the jawbone might be about 50,000 to 100,000 years older.

The jaw was found in 2002 in the collapsed Misliya cave on the western slope of Mount Carmel. Researchers spent the last 15 years looking for more remains and other fossils before publishing their study. They say the jaw belonged to a young adult of unknown gender.

The Science paper suggests modern humans could have left Africa 220,000 years ago, with some of the authors saying maybe it was even earlier. That’s in part because the cave also contained about 60,000 flint tools, mostly blades and sharp points, some of which are 250,000 years old, said study co-author Mina Weinstein-Evron.

“Now we have to write another story,” Weinstein-Evron said. “People were moving all the time.”

Scientists believe our species dispersed from Africa more than once.

The tool supply in the cave and other evidence were so complete it basically showed “industry” by the early modern humans, she said. “This guy or woman would have been very busy,” she said. “He didn’t have enough time do this. He couldn’t have made all of it. He must have had some friends.”