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The hobbit - an update -

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Robyn Williams: And so to another fossil, a human it seems, now a figure of dispute; the hobbit
from Flores. Professor Colin Groves has a clear view on the debate.

Colin Groves: The discovery of a new diminutive human-like species Homo floresiensis, popularly
known as the hobbit, burst upon an unprepared world in late 2004. The remains came from a cave,
Liang Bua, on the island of Flores in south-eastern Indonesia. The star of the show, a complete
skeleton given the registration number LB1, belonged to an individual of about one metre tall and
had a brain size of only about 400 cubic centimetres, less than a third of the average for modern
humans. It would have fitted nicely into what we already know if it had been found in Africa in
deposits dating to two million years old, but LB1 was only 18,000 years old. How to explain this?

At first the discoverers, Peter Brown, Mike Morwood and their Indonesian colleagues, proposed that
it was a dwarfed late surviving descendant of Homo erectus, a primitive fossil species that lived
in Java from over a million until perhaps just 100,000 years ago. Large mammals that find
themselves isolated on small islands typically do get smaller in size over time, a phenomenon known
as island dwarfing. Elephants, for example, are famous for having evolved dwarf representatives on
some of the Mediterranean islands at different times over the last million years or so, and in fact
the remains of a dwarf elephant-like animal, stegodon, were found in the same deposits as the
hobbit. So it was perhaps no surprise that humans, or rather proto-humans, had undergone island
dwarfing, and when they did get cut off on a smallish island.

A year later however the discoverers reconsidered this hypothesis. The similarities to those
two-million-year-old African fossils were just too strong to ignore, and the bodily and brain
proportions of the hobbit were not like you would expect in a dwarfed Homo erectus. At about the
same time a group from ANU and Sydney University, led by Debbie Argue and including yours truly,
prepared a paper supporting and extending these new ideas in some detail.

Sometimes startling discoveries like this take quite a while to become generally accepted. The very
idea of a species with pretty much a one or two-million-year-old anatomy surviving to only 18,000
years ago simply outraged some people, who spent a great deal of misplaced ingenuity trying to
dream up some convincing way in which the hobbit could be explained away as simply a pathological
modern human. They have been referred to as the sceptics, but as they have much more in common
with, say, creationists or the opponents of climate change than with the evidence-seeking
Australian sceptics. I prefer to call them simply the deniers.

The early favourite of the deniers' strategies was that LB1 was a microcephalic dwarf. Then we had
Laron syndrome, or a generalised growth defect (this one by somebody who presumably couldn't think
of anything more specific), or cretinism, or very recently a small-brained local pygmy person who
had had dental root canal therapy in the 1930s and then proceeded to get himself buried six metres
down in the floor of a cave. One of our American colleagues refers to all this as 'pathology of the
week' syndrome.

Back to science. As well as LB1, the more fragmentary remains of perhaps nine other individuals
have been found in Liang Bua, going from as early as about 75,000 to as late as 12,000 years ago, a
fact ignored by all the deniers. Where they can be compared to LB1, these other individuals tend to
be smaller. The first hobbit that struck everyone as so diminutive was actually the largest of his
kind. Moreover, the features that mark LG1's primitive status turn up in the other specimens as
well. Some of our American colleagues are working on different parts of the skeleton and their
preliminary reports on the shoulder, the wrist and the brain (the latter deduced from the imprinted
leaves on the inside of the skull) all confirm that it most resembles African fossils of about two
million years ago.

Debbie Argue continues her detailed comparisons of the cranium and Peter Brown is working on the
lower jaw, known from LB1 and from a second individual, LB6. Their comparisons too indicate that
Homo floresiensis remarkably resembles our two-million-year-old forebears. How it travelled from
Africa, how it got into Southeast Asia and how it survived isolated on Flores all that time, these
are quite unknown so far, but everything about the weird and wonderful hobbit has opened up new and
exciting avenues of research.