Is the hobbit just a dwarf cretin?
The hobbit is a modern human affected by iodine deficiency in the womb, say Australian researchers, inflaming debate once again about the origins of the creature.
"What we can see is consistent with cretinism," says Obendorf, who studies the nutrition and health of human societies through the ages.
"Compared to the other theory, that it's [the hobbit is] a new species, it really does look a better explanation."
A lack of iodine in combination with other environmental factors can destroy the thyroid gland of a child in the womb and cause greatly reduced bone growth and a reduced brain size.
Obendorf and colleagues say the characteristic features of such 'dwarf cretins' appear to be present in the hobbit fossil, which has been named a new species Homo floresiensis.
The researchers used available data and multivariant statistical analyses to compare the skull and other bones of the hobbit with those of people suffering from dwarf cretinism.
They also compared the hobbit to ancient and modern humans as well as to microcephalic humans, since one theory is the hobbit had microcephaly.
"The hobbit skull was located in amongst the cretins, nowhere near the microcephalics and well separated from the modern humans," says Obendorf.
He says the hobbit was probably a cretin that was born to a group of hunter-gatherers in central Flores.
As a child the hobbit would have been well cared for but would have been forced to become more independent as it aged, says Obendorf.
Eventually it probably became estranged from the group and died in a cave, without being buried as the normal population would have been, he says.
Obendorf says these days cretinism is far less common in Indonesia but stories abound of little people born to normal mothers, who anthropologists say disappeared in the 19th century.
He says the local people called these people Ebu Gogo or greedy ancestors, because of their pot-bellies, which are a distinctive characteristic of dwarf cretins that you can't see in fossils.
But one of the original members of the team that discovered the hobbit, Professor Peter Brown of the University of New England in Armidale, rejects the cretinism hypothesis.
"The conclusions in this paper are not supported by the facts," he says.
"The authors have not examined the original fossil, have little and no experience with fossil hominids and depend upon data obtained by others."
He says Obendorf and colleagues' argument hinges on a misinterpretation of the bones.
Professor Colin Groves of the Australian National University in Canberra says many claims are speculative.
"I regret to say that this paper cannot be regarded as a contribution to our understanding of the Flores hominin," he says.
A change of mind
Obendorf's colleague and co-author Emeritus Professor Charles Oxnard of the University of Western Australia, says he originally thought the hobbit was a new species of human because of its primitive features.
But he says when Obendorf approached him with the cretinism hypothesis, he was keen to investigate.
"I thought to myself 'Let's test it'. I think they are something primitive but I might be wrong," says Oxnard, an expert in human evolution and anatomy who has handled a model of the hobbit skull.
Oxnard says because his colleagues are not classically trained archaeologists or anthropologists they offer a different perspective on the hobbit.
"We're able to think a little bit outside the box," he says.
Obendorf says the aim is to raise a hypothesis that could be tested by others, and he now hopes to study the actual hobbit skeleton itself.
Unfortunately the casting vote of DNA evidence is still eluding researchers in the hobbit debate. This is partly because of extensive contamination by modern human DNA of material recovered from the site in Flores where the hobbit was found.
"Collection of fresh, better preserved, hobbit remains using strict anti-contamination measures currently is the best hope for testing the status of Homo floresiensis using genetic data," says Dr Jeremy Austin of the Australian Centre for Ancient DNA at the University of Adelaide.