because of differences in cranial shape and limb proportions. William Jungers and Susan Larson of the State University at Stony Brook (New York, United States) have analyzed hobbit postcranial material at recent paleoanthropology meetings. They have found limb proportion convergences with Lucy, the most famous member of Australopithecus afarensis. Still, they say, shoulder characteristics more closely match early H. erectus.
At least a genetic link to H. erectus is not geographically outrageous. H. erectus had been in the region for nearly 2 million years; in fact, the type specimen was found more than a century ago on the Indonesian island of Java.
What is a hobbit?
But, unlike big-brained erectus, whose brain was 75% of the size of ours, there is no evidence whatever that small-brained Australopiths (35% the size of ours) ever ventured out of Africa—let alone invented boats and sailed off to Indonesia more than 3 million years ago. The Argue et al. paper speculates on ways very early hominids might have migrated to the region. Something like this astounding seagoing scenario—a really, really ancient mariner—seems to be required if H. floresiensis had Australopith ancestry.
Hawks speculates that this quandary might go away if we knew more about the environmental and developmental factors that determine human body size. “We have no idea what explains body size, and the hypotheses about this are not compelling.”
Maybe LB1’s pelvis looks Australopithecine, Hawks suggests, not because the hobbits descend from a seafaring Lucy, but because that’s what the pelvis of a very small human biped looks like. “It has the virtue of not depending on external events to explain it,” Hawks says. “It’s just a consequence of being small. You still have to explain why they’re small.” If we knew why growing big or small was advantageous, we might learn whether island dwarfing applies to people as well as elephants.
Richard Potts of the Smithsonian Institution (Washington, DC, United States) suggests something similar. What would happen, he wonders, if an early, smaller-brained erectus was subjected to island dwarfing? Would ancestral Australopithecine features emerge, perhaps as a result of changes in fetal development? “We’d like to know that, but you know, we just don’t.”
Were Hobbits Toolmakers?
The debate over the hobbit brain has been fueled by stone tools found at the site. A commentary accompanying the original two papers suggested that some were like tools associated elsewhere with modern humans. This suggested to others that hobbits had a complex culture.
Stone tool experts, however, say the tools are not particularly sophisticated. They are simple, made using techniques that hominids have used for millions of years and humans are still using today.
A team led by Adam Brumm of Australian National University has tried to show that hobbits were part of a line of Flores tool makers who had been chipping sharp flakes from stone for upwards of 700,000 years. The researchers based their analysis on more than 500 stone artifacts excavated at another Flores site 50 kilometers from Liang Bua and dated between 800,000 and 740,000 years ago. No erectus remains have been found on Flores so far, but paleoanthropologists assume they made and used the tools. The paper compared the very old tools with those found at Liang Bua and noted specific similarities.
The Flores tools are unique but also simple, according to Potts. “The tools we see on Flores, the older as well as the younger, cannot be exactly matched with anything that’s known anywhere else” he says, “but the overall strategy of the technology and the overall size of the materials is consistent with what we find in mainland China.”
Harold Dibble of the University of Pennsylvania Museum agrees. They would fit perfectly at a million-year-old site, he says, but also are a type made by native Australians today. “These are simple tools,” says Dibble, “Could they have been made by a small brain? Sure.”
The Politics of Hobbitry
H. floresiensis debates have been marked by a degree of acrimony that may seem excessive and even a bit scandalous to outsiders. But a number of paleoanthropologists opine that it’s pretty much the usual fossil furor—even though it’s been punctuated by public name-calling, a high level of rancor, and exceptionally gaudy episodes like the hobbit bones’ unanticipated travels.
“I don’t think there’s anything special about this dispute except that it’s taking place in a particular cultural context of Indonesian politics, which science gets drawn into, just as it does in every other country, at least certain fields of science,” says Potts. “There are aspects of etiquette and the way of treating other people that may represent a bit of a clash between the Australian principal investigators and the Indonesian science community, which tends to be a little bit less, well, freelance about such things. I think that there may be a bit of a culture clash there.”
There are also other theories about LB1 and compatriots. Holloway, for example, says he hasn’t given up on his notion that hobbits may have been taken care of and kept as pets by other Flores H. sapiens, “sent out to fetch the wood or the occasional dead rat, bring it back, whatever!”
The most extreme proposition comes from Schwartz: “It’s an interesting assemblage of bits and pieces that probably represent different kinds of hominids and maybe even some non-hominids,” he argues. “It’s more interesting to me that there might be these different morphologies represented, and the implications of that, than to do a Rube Goldberg hominid and say, ‘Look how weird this is.’”
“To be very blunt, this is just stupid,” says co-discoverer Peter Brown. For example, he explains, LB1’s arm articulates with the skeleton, meaning they are from the same individual and not different taxa. But Brown thinks LB1’s skeletal proportions and brain size are unlikely to be due to dwarfing of H. erectus. Instead, the most likely ancestor of H. floresiensis was small-bodied and small-brained. “This is not the same as saying the ancestor was an Australopithecine.”
DNA analysis might help, but prospects are gloomy. The site is hot and wet, perfect for destroying genetic material. There’s been at least one effort to find DNA in hobbit bone, carried out in the lab of ancient DNA specialist Svante Pääbo of the Max Planck Institute (Leipzig, Germany). It failed.
So on present evidence, the debate about whether hobbits were a different kind of human or simply deformed can’t be settled. It is even possible that both sides are partly right.