A group of scientists announced Wednesday they had found 311 stone tools at a site called Talepu on the island of Sulawesi, in Indonesia, but they have not found any fossil evidence of the prehistoric humans that crafted the tools.

According to an article on Reuters, archaeologist Gerrit van den Bergh of the University of Wollongong in Australia said they now had evidence that upon the arrival of modern humans on Sulawesi some 60,000 to 50,000 years ago, they must have encountered a group of humans that had already been living in the area.

Back in 2004, fossils uncovered in a cave on the island of Flores, revealed a species of “hobbit” like humans that stood about three and a half feet tall and used stone tools and hunted small elephants, and the discovery sent a shock wave through the scientific community.  This new evidence suggests that other isolated packs of early humans may have evolved somewhat differently on other islands in the area.

Van den Berg said, “Like on Flores, where Homo floresiensis evolved under isolated conditions over a period of almost 1 million years, Sulawesi could also have harbored an isolated human lineage. And the search for fossil remains of the Talepu toolmaker is now open.”

He adds other islands in the area could have acted as human experimental zones and could shed some light on the evolution process of early humans.

The scientists are looking to unravel the mystery of how the humans traveled among the islands, and ultimately how they may have used the island chains to cross into Australia about 50,000 years in the past.  Van den Bergh speculated they may have reached Sulawesi by drifting on debris from a tsunami.

Adam Brumm, an archaeologist from Australia’s Griffith University, said the tools found at the site were made by striking stones together until smaller pieces had a knife-like sharpness.  He adds the tools were likely used for basic tasks, like shaping wooden instruments or cutting meat for food.

Fossil remains of a giant pig with tusks like a warthog, and a relative of the elephant were found nearby as well, both animals long extinct, but so far no evidence of the tool-making humans has been uncovered.

The research team published their findings in the journal Nature.