Thousands of small, sharp-edged flakes of volcanic tuff and chert have been unearthed from the cave of the "hobbit," the roughly 1-meter-tall ancient human found on the island of Flores in Indonesia. The stone tools have puzzled researchers: How could a hominid with a brain the size of a grapefruit craft tools? Now a detailed analysis sheds light on the hobbit's technological capabilities and raises a new mystery: Why did the modern humans who arrived later on Flores make tools the same way hobbits did?
Archaeologist Mark Moore of the University of New England in Armidale, Australia, and his colleagues studied 11,667 stone tools recovered from Liang Bua Cave on Flores. Excavators have unearthed hobbit bones in cave layers dated to between 17,000 and 95,000 years ago. These older layers lie beneath a layer of volcanic tuff dated to 12,000 years ago. Above that layer, at 11,000 years and younger, researchers have found Holocene burials of Homo sapiens along with more tools.
Moore's team analyzed the shapes of flakes, the position of scars left when flakes were struck off a stone, and other details to reconstruct the sequence of blows struck to make the tools. In a paper now in press at the Journal of Human Evolution, they report that hominids knapped stone in the same, simple way throughout the roughly 100,000 years represented in the cave layers. They first struck flakes off cores outside the cave. Then they brought large flakes into the cave and made smaller flakes, striking stones directly with a hammerstone or using an anvil.
Moore concludes that the hobbit, H. floresiensis, made the older tools, and then H. sapiens arrived and made similar tools. He even suggests that there was contact between the species, with modern humans copying H. floresiensis toolmakers before they went extinct: "I can see how different hominins might converge on the techniques themselves, but I find it more difficult to understand how those permutations [combinations of techniques] could be so similar without more direct observation or interaction."
The analysis gets very high marks from other archaeologists. "A model study," pronounces archaeologist John Shea of Stony Brook University in New York state. The paper also "corrects an earlier impression that these are really sophisticated tools," adds Alison Brooks of George Washington University in Washington, D.C. Some early reports had implied that the Liang Bua tools were sophisticated like those of modern humans--a finding at odds with the hobbit's tiny brain. But many archaeologists think even small-brained hominids could make this kind of simple tool.
However, when it comes to humans imitating hobbits, many archaeologists aren't yet convinced. Modern humans could have converged on the toolmaking pattern because of environmental needs, Brooks and others say. More fundamentally, with a suite of similar tools throughout the cave layers, "Homo sapiens might have made the lot of them," says Shea. He points out that modern humans were moving through the Indonesian archipelago starting about 45,000 years ago and perhaps earlier. Moore counters that some Liang Bua tools are about 100,000 years old--which was long before there's any sign of our species in the region. Having H. sapiens craft these older tools, he says, would be as surprising as humans copying hobbits.