Homo floresiensis, Australian for hobbit
David Frayer, professor of anthropology, says that the specimen, nicknamed “hobbit” after the small creatures in J.R.R. Tolkien’s “The Lord of the Rings,” was actually a female Homo sapiens dwarf.
The remains were found in Liang Bua Cave on the Indonesian island of Flores in 2003 by a research team led by Mike Morwood, archaeologist from the University of New England in Australia. The 18,000-year-old remains were believed to be a new species and were called Homo floresiensis.
Peter Brown, archaeologist from UNE and co-discoverer of the hobbit, said the hobbit may have evolved from an Australopithecine – the same genus as Lucy – that somehow made it to Flores.
“We initially thought Homo erectus moved to the island,” Brown said. “Now we think it is a small-bodied and small-brained ancestor that came to Flores. We think it was an Australopithecine.”
Frayer said that the hobbit resembles pygmies who live within a mile of Liang Bua Cave today, except that it had a smaller brain. Pygmies are people who have an average height of less than 5 feet, but don’t have dwarfism. He said that the hobbit has similar teeth to the local pygmies, who have a tradition of burying their dead in Liang Bua Cave.
When an article about the original find was published in Nature in 2004, Frayer noticed several things described in the article that indicated that the hobbit skeleton was something other than a new species.
Frayer studied photos of the hobbit and noticed that the two halves of its skull were asymmetrical. He also noted that it had a small braincase. Frayer said the brain-to-body ratio of the hobbit was only one-third of what a human of its size, about 3 feet in height, would be expected to have. This indicated to Frayer and his colleagues that the hobbit had microcephaly, a form of dwarfism characterized by having an abnormally small head with a small braincase.Brown said that the brain-to-body ratio of the hobbit was not disproportionate. He said the hobbit was about the size of a chimpanzee with the brain the size of a chimp's.
Frayer said: “The reason it was so astounding is because it had a small brain associated with complicated tools. People recognized this immediately about the hobbit. ... It’s a pathology that’s no different than any other pathology.”
Frayer also said that Flores, Indonesia, is not isolated far enough from the other islands of the Indonesian archipelago for a new species to evolve. One of the Frayer’s colleagues demonstrated that during different times of glaciation, sea levels would have been low enough that Flores wouldn’t have been separated by much, if at all, from the other islands of the Indonesian archipelago. Therefore, humans living on Flores would have been subjected to evolutionary forces like genetic drift – gene flow from outside the island – and would not have been isolated enough to evolve into a new species.
In fact, according to Frayer, Flores could have been subjected to genetic drift even if it was separated by large stretches of open sea.
“Modern humans were sailing to Australia by the sea 60,000 years ago. If not, then certainly by 30,000 years ago. It is an underappreciated aspect of human technology that early humans were sailing around a lot.”
Brown said Flores was isolated enough for a new species to evolve. He said that some of the underwater trenches around Flores are 1,000 meters deep so that no animal could have walked to the island. He said that the hobbit had floated to the island by accident.Frayer said that some scientists would argue for a new species for any skeleton that is slightly different than another specimen.
“There are people who will go find a mandible of living people, say, in Australia and then go find the mandible of a living people in Finland and some people would argue they were different species, but they know they aren't because they can interbreed,” Frayer said.
“Rather than to jumping to the conclusion that we have a new species of humans that is completely off the scale compared to other primates, let alone humans, it seems more reasonable to describe it as a pathological specimen,” Frayer said.
Brown addressed the criticisms to his research.
“They haven’t provided any evidence,” Brown said. “They have not found any modern human in Flores from that time period or any modern human with the pathology described.”
He said that Frayer’s team believes in a single lineage for human evolution and doesn’t acknowledge that there may have been many other hominid species that went extinct.
“We are happy with the belief that there were many branches in the human lineage that went extinct. Some lineages were successful, while others didn’t make it,” Brown said.
“We believe that Homo floresiensis went extinct from a volcanic eruption on Flores,” Brown said.
Jim Mielke, chairman and professor of the anthropology department, has been following the hobbit controversy.
“I find it very hard to believe that there is a different species on Flores Island,” Mielke said.
Mielke said that according to the out-of-Africa hypothesis, modern humans would have been migrating into Indonesia in the time period that the hobbit lived. The small population on Flores would have experienced genetic drift.
Like Frayer, Mielke also believes that the asymmetry of the hobbit’s skull indicates that it is not a new species.
“The asymmetry is absolutely awful, which you don’t get in human populations without pathology,” Mielke said.
Brown said that research on Homo floresiensis is continuing and that they will have a lot more researching coming out in the next year.
For ongoing commentary about the hobbit controversy, check out the John Hawks Anthropology Weblog.