In some ways, the latest theory about the enigmatic Flores bones is even more revolutionary than the original claim. “The possibility that a very primitive member of the genus Homo left Africa, perhaps roughly two million years ago, and that a descendant population persisted until only several thousand years ago, is one of the more provocative hypotheses to have emerged in paleoanthropology during the past few years,” reflects David S. Strait of the University at Albany S.U.N.Y. Scientists have long believed that H. erectus was the first member of the human family to march out of the natal continent and colonize new lands because that is the hominin whose remains appear outside of Africa earliest in the fossil record. In explanation, it was proposed that humans needed to evolve large brains and long striding limbs and to invent sophisticated technology before they could finally leave their homeland.
Today the oldest unequivocal evidence of humans outside of Africa comes from the Republic of Georgia, where researchers have recovered H. erectus remains dating to 1.78 million years ago. The discovery of the Georgian remains dispelled that notion of a brawny trailblazer with a tricked-out toolkit because they were on the small side for H. erectus, and they made Oldowan tools, rather than the advanced, so-called Acheulean implements experts expected the first pioneers to make. Nevertheless, they were H. erectus.
But if proponents of the new view of hobbits are right, the first intercontinental migrations were undertaken hundreds of thousands of years earlier than that—and by a fundamentally different kind of human, one that arguably had more in common with primitive little Lucy than the colonizer paleoanthropologists had envisioned. This scenario implies that scientists might locate a long-lost chapter of human prehistory in the form of a two-million-year record of this pioneer stretching between Africa and Southeast Asia if they look in the right places.
This suggestion does not sit well with some researchers. “The further back we try to push the divergence of the Flores [hominin], the more difficult it becomes to explain why a [hominin] lineage that must have originated in Africa has left only one trace on the tiny island of Flores,” comments primate evolution expert Robert Martin of the Field Museum in Chicago. Martin is unconvinced that H. floresiensis is a legitimate new species. In his view, the possibility that LB1—the only hobbit whose brain size is known—was a modern human with an as yet unidentified disorder that gave rise to a small brain has not been ruled out. The question is whether such a condition can also explain the australopithecinelike body of LB1.
Many scientists are welcoming the shake-up. LB1 is “a hominin that no one would be saying anything about if we found it in Africa two million years ago,” asserts Matthew W. Tocheri of the Smithsonian Institution, who has analyzed the wrist bones of the hobbits. “The problem is that we're finding it in Indonesia in essentially modern times.” The good news, he adds, is that it suggests more such finds remain to be recovered.
“Given how little we know about the Asian hominin record, there is plenty of room for surprises,” observes Robin W. Dennell of the University of Sheffield in England. Dennell has postulated that even the australopithecines might have left Africa, because the grasslands they had colonized in Africa by three million years ago extended into Asia. “What we need, of course, are more discoveries—from Flores, neighboring islands such as Sulawesi, mainland Southeast Asia or anywhere else in Asia,” he says.
Morwood, for his part, is attempting to do just that. In addition to the work at Liang Bua and the Soa Basin of central Flores, he is helping to coordinate two projects on Sulawesi. He is eyeing Borneo, too. Searching the mainland for the ancestors of the Liang Bua hobbits will be difficult, however, because rocks of the right age are rarely exposed in this part of the world. But with stakes this high, such challenges are unlikely to prevent intrepid fossil hunters from trying. “If we don't find something in the next 15 years or so in that part of the world, I might start wondering whether we got this wrong,” Tocheri reflects. “The predictions are that we should find a whole bunch more.”