At first we thought it was a child, perhaps three years old. But a closer look showed that the tiny, fragile bones we had just laid bare in a spacious cave on the Indonesian island of Flores belonged to a full-grown adult just over three feet tall.
Had we simply found a modern human stunted by disease or malnutrition? No. The bones looked primitive, and other remains from Liang Bua, which means "cool cave" in the local Manggarai language, showed that this skeleton wasn't unique. It was typical of a whole population of tiny beings who once lived on this remote island. We had discovered a new kind of human.
Back in the lab, where we analyzed the bones and other artifacts, the full dimensions of what we had discovered began to emerge. This tiny human relative, whom we nicknamed Hobbit, lived just 18,000 years ago, a time when modern humans—people like us—were on the march around the globe. Yet it looked more like a diminutive version of human ancestors a hundred times older, from the other end of Asia.
We had stumbled on a lost world: pygmy survivors from an earlier era, hanging on far from the main currents of human prehistory. Who were they? And what does this lost relative tell us about our evolutionary past?
A 220-mile-long (354 kilometer) island between mainland Asia and Australia, Flores was never connected by land bridges to either continent. Even at times of low sea level, island-hopping to Flores from mainland Asia involved sea crossings of up to 15 miles (24 kilometer). Before modern humans began ferrying animals such as monkeys, pigs, and dogs to the island about 4,000 years ago, the only land mammals to reach it were stegodonts (extinct elephant ancestors) and rodents—the former by swimming and the latter by hitching a ride on flotsam. No people could have reached Flores until modern humans came along, with the brainpower needed to build boats. Or so most scientists believed.
Yet in the 1950s and '60s Theodor Verhoeven, a priest and part-time archaeologist, had found signs of an early human presence. In the Soa Basin of Flores he found stone artifacts near stegodont fossils, thought to be around 750,000 years old. Homo erectus, an archaic hominin (a term for humans and their relatives), was known to have lived on nearby Java at least 1.5 million years ago, so Verhoeven concluded that erectus somehow crossed the sea to Flores.
As an amateur making extraordinary claims, Verhoeven failed to persuade the archaeological establishment. In the 1990s, however, other researchers used modern techniques to date tools from the Soa Basin to about 840,000 years ago. Verhoeven was right: Human ancestors had reached Flores long before modern humans landed. But no actual remains of Flores's earlier inhabitants had ever turned up.
So we went looking, focusing on Liang Bua, in the uplands of western Flores. By September 2003 our team of Indonesian and Australian researchers, assisted by 35 Manggarai workers, had dug 20 feet into the cave floor. Younger layers were rich in stone artifacts and animal bones, but by this point the dig seemed played out.
Then, a few days before the three-month excavation was due to end, our luck changed. A slice of bone was the first hint. The top of a skull appeared next, followed by the jaw, pelvis, and a set of leg bones still joined together—almost the entire skeleton of Hobbit.
We knew we had made a stunning discovery, but we didn't dare remove the bones for a closer look. The waterlogged skeleton was as fragile as wet blotting paper, so we left it in place for three days to dry, applied a hardener, then excavated the remains in whole blocks of deposit.
Cradled in our laps, the skeleton accompanied us on the flight back to Jakarta, Indonesia's capital. There Peter Brown, a paleoanthropologist from the University of New England in Australia, supervised cleaning, conservation, and analysis. The pelvic structure told him Hobbit was a female, and her tooth wear confirmed that she was an adult. Her sloping forehead, arched browridges, and nutcracker jaw resembled those of Homo erectus, but her size was unique.
It wasn't just her small stature and estimated weight—about 55 pounds (25 kilograms)—but a startlingly small brain as well. Brown calculated its volume at less than a third of a modern human's. Hobbit had by far the smallest brain of any member of the genus Homo. It was small even for a chimpanzee.
The tiny skull is most reminiscent not of the hefty Homo erectus from elsewhere in East Asia but of older, smaller erectus fossils. Viewed from above, the skull is pinched in at the temples, a feature also seen in the 1.77-million-year-old Dmanisi people from Georgia, in western Asia. And in some respects, such as the shape of her lower jaw, the Liang Bua hominin harks back to even earlier fossils such as Lucy, the 3.2-million-year-old Australopithecus from Ethiopia.
And yet—strangest of all—she lived practically yesterday. Radiocarbon dating of charcoal pieces found next to the skeleton, together with luminescence dating that indicated when the surrounding sediments were last exposed to the sun, revealed her 18,000-year age. By mid-2004 our excavation at Liang Bua had yielded bones and teeth from at least six other individuals, from about 95,000 until as recently as 13,000 years ago.
For a few skeptics, all this is too much to swallow. They argue that the one complete skull must have come from a modern human with a rare condition called microcephaly, in which the brain is shrunken and the body dwarfed. The other small bones, they say, might be the remains of children. But last year's discoveries include part of a second adult skull—a lower jaw—that is just as small as the first. It simply strains credibility to invoke a rare disease a second time.
Instead, Hobbit is our first glimpse of an entirely new human species: Homo floresiensis. Her kind probably evolved from an earlier Homo erectus population, likely the makers of the tools Verhoeven found. Her ancestors may have stood several feet taller at first. But over hundreds of thousands of years of isolation on Flores, they dwindled in size.
Such dwarfing is often the fate of large mammals marooned on islands. There they generally face fewer predators—on Flores, Komodo dragons were the only threat—which makes size and strength less important. And the scarce food resources on a small island turn a large, calorie-hungry body into a liability. On mainland Asia, stegodonts sometimes grew bigger than African elephants; at Liang Bua they were only a bit bigger than present-day water buffalo.
In the past some anthropologists have argued that even in prehistory humans could adapt to new environments by inventing new tools or behaviors rather than by physically evolving, like other creatures. The dwarfing seen on Flores is powerful evidence that humans aren't exempt from natural selection. The discovery of Hobbit is also a hint that still other human variants may once have inhabited remote corners of the world.
In spite of their downsized brains, the little people apparently had sophisticated technology. The fireplaces, charred bones, and thousands of stone tools we found among their remains must have been their handiwork, for we found no sign of modern humans. Stone points, probably once hafted onto spears, turned up among stegodont bones, some of which bore cut marks. The little hominins were apparently hunting the biggest animals around. It was surely a group activity—adult stegodonts, although dwarfed, still weighed more than 800 pounds (363 kilograms), formidable prey for hunters the size of preschool children.
The discovery underscores a puzzle going back to Theodor Verhoeven: How could ancient hominins ever have reached Flores? Was Homo erectus a better mariner than anyone suspected, able to build rafts and plan voyages? And it raises a new and haunting question. Modern humans colonized Australia from mainland Asia about 50,000 years ago, populating Indonesia on their way. Did they and the hobbits ever meet?
There's no sign of modern humans at Liang Bua before 11,000 years ago, following a large volcanic eruption that would have wiped out any Homo floresiensis in the region. But other bands may have hung on elsewhere in Flores. Perhaps modern humans did meet their ancient neighbors before something—maybe a changing environment, maybe competition or conflict with modern humans themselves—spelled the end for the little people. Further excavations on Flores, and on nearby islands that might have had their own hobbits, may settle the question.
In the meantime a clue may come from local folktales about half-size, hairy people with flat foreheads—stories the islanders tell even today. It's breathtaking to think that modern humans may still have a folk memory of sharing the planet with another species of human, like us but unfathomably different.
The Australian Research Council supported this work; your Society will help sponsor future study.
Could this be the face—shown life-size—of a lost human species that stood three feet tall and inhabited an isolated island world?
Synthetic skin and hair bring to life the cast of an 18,000-year-old skull of a female. Her remains were found with those of six other tiny beings on Flores, where they hunted creatures from giant rats to Komodo dragons and made stone tools—all with brains smaller than a chimp's.
Miniature beings with skulls far smaller than our own sprang from an ancient line of human ancestors. How did they reach—and survive on—a remote Indonesian island?
Thomas Sutikna of the Indonesian Centre for Archaeology holds a skull that he and fellow scientists believe represents a new human species, Homo floresiensis. Found in a cave on Flores (map), the species existed alongside modern humans as recently as 13,000 years ago, yet may descend from Homo erectus, which arose some two million years ago.
No ancient humans could have reached flores before big-brained modern people—or so it seemed.
The first itinerant humans, Homo erectus, crossed land bridges from Asia to Indonesia. But their trail seemed to end at Java (above), the site of Homo erectus bones at least 1.5 million years old. No one believed these early humans could cross the ocean barrier called Wallace's line. Scientists thought it wasn't until 50,000 years ago that people—modern Homo sapiens—made the jump. But 840,000-year-old stone tools found in the Soa Basin on Flores are a sign that Homo erectus crossed Wallace's line much earlier. "How they managed to get there is still a real mystery," says Mike Morwood of the University of New England in Australia.
Looking for signs of early humans, archaeologists Wahyu Saptomo and Mike Morwood (below) examine stone artifacts found buried in a limestone cave that the local Manggarai people call Liang Bua. Above its massiveentrance (above right) gray stalactites hang like jagged fangs, but the grim exterior belies an inner beauty. "It's very much like a cathedral inside," says Morwood, who has excavated here since 2001. He says islanders have used the cave as a burial ground for millennia. The dirt below its clay floor is riddled with human bones from a range of eras. But Morwood is interested in the cave's first occupants, Homo floresiensis, who arrived at least 95,000 years ago. The search has involved hauling tons of dirt bucket by bucket to a washing station set up in a nearby rice field (above left), where researchers sifted artifacts and bones from the mud. The work paid off with the discovery of remains from at least seven tiny individuals. The team also found well-flaked stone points—possibly spearheads—that suggest Homo floresiensis, although much smaller than its Homo erectus ancestors, was also smarter.
For millennia the only land mammals on flores were rodents, stegodonts, and humans.
The Homo floresiensis skeleton stands roughly half as tall as a modern adult's. "I knew within about 60 seconds of seeing the jawbone that this was something entirely new," says paleoanthropologist Peter Brown, who examined the bones. The premolars are a giveaway, with a root much different from ours. The pelvis of this female is also wider than in Homo sapiens. Her arms hung almost to her knees, says Brown, but her delicate hand and wrist bones imply that "she wasn't doing a lot of climbing."
Why were the Flores humans so small? Biogeographer Mark Lomolino, who studies the phenomenon called island dwarfism, says, "We know that when evolutionary pressures change, some species respond by shrinking." Stegodonts—extinct elephant ancestors—were especially prone to dwarfing, because they often colonized islands. "Elephants are strong swimmers," he says. Once there, with limited food and fewer predators, they shrank. On Sicily, Crete, and Malta, scientists have unearthed bones from primitive elephants as little as a twentieth the size of mainland forms. But other species, such as rats, tend to grow larger in a place without competitors. Flores yielded remains of giant rats and lizards, as well as cow-size dwarf stegodonts and diminutive human bones (shown above with stone tools and stegodont teeth). Peter Brown says the tiny Homo floresiensis may have evolved from a population of Homo erectus that reached Flores some 800,000 years ago. "The problem is we haven't found Homo erectus bones," says Brown. "All we have is these small-bodied people."