Saturday, 28 January 2012
The Enigma of the Indonesian Hobbits
Every so often a discovery is made that rocks the archaeological world to its core. One of these amazing discoveries was the uncovering of a strange, diminutive hominid skeleton on the island of Flores in Indonesia. Nicknamed the ‘Hobbit’, the remains of the this new dwarf species of human was discovered in 2003 in the vast limestone caves at Liang Bua Cave by a joint Australian-Indonesian team led by Mike Morwood from Australia’s Wollongong University. At the time, Morwood’s team were investigating whether there was any evidence for the migration of H. erectus, an early human species, from Asia to Australia and were very surprised to come across a brand new species of early human. This new species was named H. Floresiensis, and from the start these ancient human remains have been the cause of much speculations, disagreement and debate among the scientific community.
To date, partial skeletons of nine individuals have been unearthed including one complete skull. The most complete skeleton is known as LB1, and by the pelvis is judged to be a female who was around the age of thirty when she died. Because of the very damp conditions in the Liang Bua caves and the relatively recent age of the remains, the skeleton had not been fossilised and the bones were in a very fragile condition when they were found. The ‘hobbit’ remains are remarkable for several reasons. The single most surprising thing is their small stature; they stood only about 1 metre tall and were fully bipedal. They also had a very small brain size, around 417cc. This brain size is smaller than the brain size range of chimpanzees, which is between 300 to 500cc, and also those of the Australopithecines, who were a species of very early human. These ‘hobbits’ had human like teeth, but had a receding forehead and no chin. The bone structure of the wrists, shoulders and arms are also proved to be more similar to those of chimpanzees and Australopithecines than modern humans or H. erectus in a 2007 study.
So how old were these remarkable skeletal remains of a new species of dwarf human? The fossil skeletons range from being between 38,000 and 18,000 years old, but other archaeological evidence such as stone tools suggests that H. floresiensis inhabited the island of Flores from as long ago as 95,000 years ago and up to as recently as 13,000 years ago. This makes the ‘Hobbits’ the last-known surviving non-modern humans in the world, as the Neanderthals had last walked the earth about 35,000 years ago. As modern humans arrived on Flores between 55,000 and 35,000 years ago, these two very different species of human would have presumably shared territory and interacted with each other for thousands of years, although there is no archaeological proof of this.
There are theories that the ‘hobbits’ survived until much more recently and could even still be alive today, deep in the unexplored tropical rainforests of Indonesia. Folklore on Flores speaks of a strange creature called Ebu Gogo who were small, human-like cave-dwellers who did not communicate and walked with a strange gait. Reputedly they were covered in hair and had broad faces and large mouths. The Ebu Gogo were known for stealing human crops and kidnapping children, so the legend goes that sometime in the 18th century the Flores Islanders tricked the Ebu Gogo into accepting gifts of rattan mats. As they returned to their caves with these mats, the Flores Islanders followed them and set fire to the mats killing nearly all of the Ebu Gogo, except perhaps for one couple who escaped to continue on the Ebu Gogo line. Also, on the Indonesian island of Sumatra, deep in the jungle, sightings are still reported of a 1.5 metre high hominid the locals call Orang Pendek, which is Indonesian for short person. But why would H. floresiensis suddenly die out 12,000 years ago after surviving successfully for so many thousands of years? It is thought that a volcanic eruption in the region 12,000 years ago could have been responsible for the demise of the ‘Hobbits’, the same eruption that led to the extinction of the pygmy elephant Stegodon on Flores.
H. floresiensis was an unexpected discovery and it was a big surprise that a non-modern human species existed on the earth until so recently and was so small in stature, but what other controversy did the discovery of the ‘Hobbits’ cause. Well, the big debate is where they came from and how they evolved. Some experts believe that they were a direct descendant of H. erectus, and that for some reason there had been active selection for smaller brain size and stature. So did the ‘Hobbits’ shrink over thousands of years because of the evolutionary pressures caused by being on an island with limited resources? Don’t forget that Flores had also been home to a species of dwarf elephants that had adapted to their environment and shrunk, and these dwarf elephants had been an important food source for the ‘hobbits’. However, the study of the H. floresiensis wrist bones showed them to be nothing like H. erectus carpal bones, as the ‘hobbit’ wrist bones lack features that had been present in early species of modern humans from at least 800,000 years ago. If H. Floresiensis were a dwarf variation of these earlier humans, it challenges the traditional view that H. erectus could not cross sea barriers. The island of Flores has always been separated from its neighbour Java by a deep sea barrier, so if H. erectus was living on Flores, and in 1998 Mike Morwood announced the discovery of stone tools believed to have been made by these early humans dating back 840,000 years, then this theory is totally overturned and they were indeed capable of travelling by sea.
However, an even more daring theory is that the ‘hobbits’ evolved directly from Australopithecines, who were some of our very earliest human ancestors. Australopithecus first emerged around seven million years ago in the Rift Valley of East Africa, and australopithecine fossils show great similarities to the remains of the ‘Hobbits’, including small brain size, small stature and primitive wrist bones, teeth and feet. This would mean that H. floresiensis did not shrink due to environmental pressures, but started off small and stayed small. But the most startling aspect of this theory is that Australopithecus was not previously thought to have ever left Africa. The first modern human migration from Africa was believed to have occurred around 65,000 years ago, with small bands of our early ancestors migrating out of Africa via the coastal routes through the Middle East and maybe making the short sea crossing to Arabia. If the ‘hobbits’ were descended from Australopithecus it meant that Australopithecines possessed hitherto undiscovered seafaring abilities and also that they possibly migrated out of Africa into Asia millions of years before any species of human was thought to have done? Mike Morwood has now uncovered stone tools on nearby Sulawesi that could be almost 2 million years old, so will more H. floresiensis skeletons and archaeological artefacts be discovered that could provide further vital evidence?
There are some experts who argue that the controversial ‘hobbit’ remains are just modern human skeletons that are somehow abnormal and that the individuals suffered from a disease such as microcephaly that leads to small brain sizes. However, all of the ‘hobbit’ skeletons display the same features and that they are just too different from modern humans to simply be diseased modern humans. What might be able to settle the argument is if some mitochondrial DNA is recovered from the H. floresiensis specimens and sent for analysis. However the hot, damp climate of the Liang Bua caves reduces the chances of it being recovered, as extreme heat degrades DNA. In addition, the bones were not fossilised, which also does not help DNA recovery.
Hopefully, future discoveries will throw further light on where the ‘hobbits’ came from and how they evolved. Also, they may give us more information on when the first humans really did leave Africa to spread to other parts of the world. Of course, the most amazing thing would be if a population of diminutive ‘hobbits’ were discovered to be still living today deep in the tropical jungles of Indonesia, and then suddenly we would not be the only human species alive on our planet today.
H. floresiensis skull image FunkMonk Wikimedia Commons Creative Commons Attribution Share Alike 2.0 Generic