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Local folktales on the Indonesian island of Flores, some 350 miles west of Bali, tell of a race of shy little people — South Seas leprechauns who inhabited the limestone caves that dot the island, accepting gourds full of food that the Floresians would set out for them. It wasn't until Dutch traders arrived in the 1500s, according to the legends, that the diminutive race finally disappeared.
Western scientists have long dismissed these stories as pure fancy, but now they are having second thoughts. In a report that rocked the world of paleoanthropology last week, a team of Australian and Indonesian scientists announced in Nature that they had discovered that a tribe of tiny humans, only about 3 ft. tall, did indeed live in the caves of Flores. Digging into the sediments on the floor of a cave called Liang Bua, the team found bones from seven individuals, including the nearly intact skeleton of an adult female they nicknamed the Hobbit. And while there's no proof that the little people survived later than about 13,000 years ago, it's not beyond the realm of possibility.
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What makes the discovery truly shocking is that the beings were not, like the Pygmies of equatorial Africa, just a short variety of modern Homo sapiens. Dubbed Homo floresiensis, they represent an entirely new twig on the human family tree. Until now, scientists believed that Neanderthals, who died out some 30,000 years ago, were the only human species that coexisted for any length of time with people like us. The chapter of biology textbooks that describes our family tree will have to be rewritten.
Unlike Neanderthals, moreover, H. floresiensis wasn't a close evolutionary relative. Its discoverers are convinced that it evolved from Homo erectus, a primitive branch of humanity whose line was thought to have been entirely supplanted by modern humans about 250,000 years ago. And while the general trend in human evolution over the past 7 million years or so has been toward larger bodies and larger brains, H. floresiensis went the other way: not only was its body small but, again unlike Pygmy or midget H. sapiens, its brain was only about the size of a grapefruit — smaller than that of a chimpanzee. "To think," says Nature senior editor Henry Gee, "that these creatures were evolving on their island while there were perfectly modern humans all around the place — it's astonishing."
Uncovering a new species was the last thing the scientists expected when they began excavating in Liang Bua. They were on the trail of H. erectus, which arose in Africa but had spread all the way to Southeast Asia by 1.8 million years ago (the celebrated Java Man was the first to be discovered). Previous excavations in central Flores had already uncovered primitive stone tools, dating to about 800,000 years ago, mixed in with fossils of an extinct species of dwarf elephant known as Stegodon.
Reasoning that caves would be the best places in which to find undisturbed fossils, team leaders Michael Morwood of the University of New England in Armidale, Australia, and R.P. Soejono from the Indonesian Centre for Archaeology in Jakarta decided to dig in Liang Bua, in the western part of the island. Limited excavations there had revealed evidence of human habitation.
The team had dug about 20 ft. down into the cave floor by September of last year when they came upon the tiny skull, and with it a nearly complete skeleton. The body was only about the size of a modern 3-year-old. "At first we were sure we'd found a child," says Morwood. On closer examination, though, the extent of wear on the teeth, evidence that the third molars had come in and the maturity of the limb bones made it clear that they were dealing with a fully grown adult. The shape of the pelvis showed that the skeleton was female, and several dating techniques indicated that it lived as recently as 18,000 years ago. Ultimately the team found fragments of six more individuals, the oldest from 95,000 years ago and the youngest from a mere 13,000 years ago.
From the start, says Morwood, "it was pretty obvious that this was not a modern human. It had a big brow and a massive nutcracker jaw," some of the telltale characteristics of H. erectus. But, he says, "it's very unlike the Homo erectus you get in Java." In fact, he believes the Hobbit most closely resembles specimens found in the Republic of Georgia that date back 1.7 million years. "It's obvious," Morwood says, "that human evolution has been much more complex than we'd realized."
It's even more obvious when you consider the Hobbit's diminutive size. The creature clearly wasn't an ape. It resembled the famous Lucy in stature and brain size, but the shape of the skull is very different; besides, Lucy is more than 3 million years older. The tiny brain also rules out the theory that this was a type of Pygmy, midget or dwarf, whose brains are all comparable in scale to those of full-size adults. But evolution does provide an explanation, known to biologists as the Island Rule: when isolated on small islands in the absence of big predators, large mammals tend to evolve toward smaller sizes. That's because they don't need to fight off attackers and because smaller individuals can get by better on limited resources. (Paradoxically, small animals on islands tend to grow larger, and Flores was populated with giant rats and lizards, including Komodo dragons.)
The Island Rule is almost certainly the reason Stegodon dwindled to the size of a water buffalo on Flores. But while examples of such shrinkage had been found in elephants, hippos and deer, it was unheard of in higher primates. "It shows that hominids are following the same evolutionary and ecological rules as other mammals," says paleontologist Tim White of the University of California, Berkeley. "Wallace and Darwin would have been delighted."
Despite their minuscule brains, the Hobbit and her kin were evidently smart enough to use fire, make tools and hunt, challenging existing notions of the relationship of brain size to intelligence. The scientists found bones of Stegodon, Komodo dragons and an assortment of rodents and other animals in the Liang Bua sediments, some of them charred by what may have been cooking fires.
The scientists also unearthed stone tools, including sophisticated points, blades, awls and tiny barbs that were probably attached to sticks to make spears. Although the evidence is circumstantial, Morwood and his team are convinced that the tools were made by H. floresiensis. Even though modern humans were living in the region at the same time, their bones don't appear in the layers with the tools. If the two species were contemporaries, of course, there is also the disturbing possibility that we killed and ate our smaller cousins — although there is no evidence to support that horrifying idea.
Besides some basic evolutionary questions, the presence of the Hobbit on Flores raises a practical one as well: How did her ancestors get there in the first place? Unlike elephants, which are surprisingly buoyant, they couldn't have swum the roughly 12 miles that separated Flores from the nearest land even when sea level was at its lowest. Rats and other small mammals could have floated over on flotsam, but if the first human settlers had hitched a ride on tree trunks or large mats of vegetation, you would expect other large mammals — pigs, deer, monkeys, tigers — to have done so as well.
Morwood theorizes that the Hobbit's ancestors must have built primitive rafts of bamboo; members of the team even constructed their own, à la Kon-Tiki, to prove it could be done. That would have been a technological feat far beyond anything H. erectus had ever been credited with, and some paleoanthropologists are skeptical. Not all, though. Says Chris Stringer, head of the Human Origins department at the London Natural History Museum: "The most likely explanation, as difficult as it is for me to accept, is that they used some kind of watercraft." Morwood goes a step further, suggesting that to achieve the kind of cooperation required to build rafts, H. floresiensis must have had language.
That's too speculative for most of his colleagues to accept at this point. But some of Morwood's other theories are being taken quite seriously. If the Hobbits evolved in isolation on Flores, there is every reason to believe that the same thing happened on other nearby islands. "I think we're going to have a plethora of new human species showing up," he says. Moreover, if the creatures survived all the way to 13,000 years ago, it's not at all impossible that they survived much longer — perhaps long enough to provide a factual basis for the Floresian folktales.
And if the Hobbits hung on until as recently as 500 years ago, it is conceivable, though admittedly very far-fetched, that pockets survive even today — if not on Flores, then on other remote Pacific islands. "The probability is that they're extinct," says Stringer. "But since this is such an astounding and surprising find, I think it shows how little we know about events in Southeast Asia. You really have to keep an open mind."
- Michael D. Lemonick