Thousands of years ago, hobbits roamed a lush, green land. They gathered food, took shelter in cozy holes in the earth, and even battled dragons. This is no fantasy epic—it’s the likely lifestyle of an ancient human relative that thrived on the island of Flores in Indonesia.
Discovered in 2003 in Liang Bua cave, Homo floresiensis stood about three and a half feet (1.1 meters) tall and weighed around 75 pounds (35 kilograms). Nicknamed for the diminutive heroes in J.R.R. Tolkien's famous novels, the real-life hobbits made stone tools and might have survived predatory attacks from komodo dragons. Even more exciting to anthropologists, the discovery team originally estimated that these “halflings” lived as recently as 12,000 years ago, which would mean that they outlived Neanderthals and might well have crossed paths with modern humans.
However, a fresh look at the site where the fossils were found puts a twist on the tale: The latest evidence suggests that hobbits vanished from the island far earlier than thought, casting the chances of a cross-species encounter in a new light.
“Since 2007, a lot more of the cave has been excavated,” says study co-author Matthew Tocheri of Lakehead University in Thunder Bay, Ontario. Researchers initially used chemical clues in the soil around the fossils to figure out when layers of sediment were laid down and thus how old the bones and tools found inside them must be. In the latest work, the team found that the layers of sediment in the cave were not all evenly deposited and so varied widely in age even at similar depths.
The new analysis, published today in Nature, asserts that the skeletal remains of H. floresiensis are more likely between 100,000 and 60,000 years old, and their stone tools date from as far back as 190,000 years to around 50,000 years ago. That suggests these evolutionary cousins did not exist for long after modern humans arrived in the region some 50,000 years ago.
“At the time of the initial discovery, not enough of the older deposits had been exposed, and this led to an error in the interpretation of how the dates obtained at that time applied to the sediments that contained the hobbit remains,” says Tocheri, who received funding from the National Geographic Society's Waitt Grants Program for this work.
While earlier investigations focused on the cave’s center and eastern wall, the current study, conducted by many of the same researchers, expanded excavations between these areas and toward the rear of the cave. Older deposits in certain sections of the cave had eroded away, creating a steep slope near the entrance that became filled in with younger sediments, which caused the original misinterpretation.
To ensure that the new age estimates are accurate, the team used five independent dating methods, ranging from the uranium decay rate in bone to luminescence in soil, which measures the amount of time since sand was last exposed to sunlight.
The erosion may also explain why excavators were unable to find all the bones from the upper body of the first known hobbit specimen. According to Tocheri, “if the erosion had continued for just a little longer, then the entire skeleton would more than likely have been lost forever.”
But age is just one of many bones of contention regarding H. floresiensis. Since the initial discovery, at least six additional hobbits have been exhumed in the cave, and biological anthropologists have been wrestling with issues ranging from how they first migrated to Indonesia, to the reasons for their diminutive size, to whether they even qualify as a unique human species.
“Every finding just makes it more mysterious,” says Ian Tattersall, a paleoanthropologist and emeritus curator at the American Museum of Natural History who was not involved in the study. “Nobody could ever have imagined a hominid that looked like the one from Flores. It’s the kind of thing only nature could come up with.”
Some experts contended that the hobbit’s stature and small brain—about one-third the size of an adult human’s—mean that the fossils belong to diseased modern humans with dwarfism, Down syndrome, or microcephaly, a developmental condition that produces a small head. Though many of these theories still circulate, a 2007 analysis conducted by Tocheri revealed that the wrist bones of H. floresiensis had very little structural similarity to modern humans and were more comparable to early hominins and chimpanzees, providing strong evidence for a separate species.
The prevailing theory is that H. floresiensis is either a descendent of a hominin that arrived on Indonesia in hobbit form, or a descendent of Homo erectus that evolved into its smaller stature once on the island. This evolutionary process, called island dwarfism, occurs when a species becomes progressively smaller to reduce its food requirements on a resource-deficient island. The excavation site at Liang Bua was littered with remnants of pygmy elephants, which adds credence to this theory.
Not a Fellowship?
Though no direct evidence from Liang Bua shows any interaction with modern humans, Tattersall still believes it is possible that these ancestral cousins could have crossed paths, perhaps with disastrous consequences.
“There is this pattern where ancient kinds of Homo that have been doing perfectly well for a very long time disappear as soon as Homo sapiens shows up. For one reason or another, Homo sapiens is an insuperable competitor,” says Tattersall.
And the new estimates for hobbit extinction coincide suspiciously with the arrival of modern humans in that area.
“The thing that I find most intriguing about the new work is its implications on how H. floresiensis went extinct,” says Rick Potts, director of the Smithsonian’s Human Origins Program and curator of anthropology at the National Museum of Natural History. “Island populations are always under threat due to fluctuations in food supply, and it could be that H. floresiensis went extinct on its own. But it also happens to coincide with the moment in time when Homo sapiens was in the neighborhood.”
Further excavations of Liang Bua and other sites on Flores could offer more clues and answer essential questions about the development, lifestyle, and extinction of this mysterious species.
“Many of these research questions will be answered by the team’s continuing work,” says Potts. “It’s going to be fascinating no matter what.”