Picture: Cicero Moraes et alii
How We Discovered Our Strangest Relative…
Dragons and Dwarf Elephants
Flores is a medium sized island, in the Indonesian archipelago, that has been cut-off from any continental landmass for a very long time. Although, sea levels were much lower during the Ice Age, making it easier for many animals to make the short swim across from other islands. Despite not being as isolated as some of the other locations covered in this series, this didn’t stop Flores developing its own unique wildlife. Some of these animals, such as the Komodo dragon and Flores giant rat, still stalk the island today.
The Komodo dragon’s origins don’t appear to be the same as other island giants. Whilst biologists used to think it evolved into the title of ‘largest lizard in the world’ on the Indonesian archipelago, a recent study has shown they actually made their way north from Australia; when a land bridge still existed with the islands. When sea levels rose, these populations became isolated and survived, whilst going extinct elsewhere. The study also showed the dragon’s size has remained fairly consistent since its exodus from down under.
Whilst the dragons may actually be Australian relics, clinging onto life on a few scraps of land, there is little doubt the Flores giant rat is a genuine example of island gigantism. They can grow to be twice as long and eight times as massive as the brown rats we’ve all seen scurrying around our cities.
Other species native to Flores, such as the dwarf Stegodon, a type of elephant, and L. Robustus, a giant marabou stork, are long gone. Probably going extinct about 50,000 years ago, not long after a volcanic eruption on the island. Stegodons are believed to have been the primary food source for the Komodo dragons, until modern humans brought pigs and buffalo with them; making Flores a place where lizards hunted elephants! Much speculation abounds about the marabous, due to their fragmentary remains, but it is hypothesised that they were ground-dwelling and carnivorous. Possibly preying on giant rats and young dragons.
However, there is one creature that was found on Flores that has caught the imagination like no other…
The discovery of stone tools on Flores, dating back 840,000 years, in the 90s, sparked a lot of confusion and curiosity. As far as we knew, there were only a few contenders around at the time who could have made these items and all posed huge questions. It couldn’t have been Homo Sapiens (modern humans). Current genetic and fossil evidence points to us evolving around 300,000 years ago in East Africa; and we weren’t supposed to reach this region of Asia until around 50,000 years ago. It was a similar story for Neanderthals, Homo Heidelbergensis and the Denisovans. Their temporal and/or geographic ranges eliminated them from contention (well, the Denisovans weren’t in contention because they hadn’t even been discovered at this point, but that’s another story).
We know Homo Habilis was around at this time but their fossils have never been found outside of Africa. If they were made by our cousins, Homo Erectus, then this poses the problem of how they managed to get their backsides over to Flores in the first place? As we have no evidence, circumstantial or otherwise, that they were able to build boats. Oceans had always stopped their progress before. Perhaps a population had reached here during the time of a land bridge and become isolated? That seemed the best option anyone had come up with so far. Yet, when the archaeologists trotted on down to Flores and started digging, what they found was much stranger than any of their preemptive theories.
After excavating deep into the soil at Liang Bua cave, human remains were found, amongst Stegodon, giant stork and copious rat fossils. However, the fragile skull was much smaller than a modern human’s. At first, the dig team thought it belonged to a child. However, the top expert on identifying animal remains disagreed, he said it was a new species entirely. Getting a conclusive answer was difficult, as the delicate relic could not be removed from the sediment safely. So, they removed the sediment as well. Phone calls were made as a block of earth containing the fossil was taken back to a hotel, so it could be extracted more easily. When experts on human skeletons examined the skull, it was confirmed. These weren’t H. Sapiens, adults were only just over a metre tall and they had a brain volume of just 400 cubic centimetres. A new species of miniature human, affectionately dubbed ‘the hobbit’, had been discovered and it lived on Flores only 12,000 years ago…or did it?
Controversy began to swirl around the specimen. First, it was accosted (read: stolen) from the team who discovered it by senior Indonesian archaeologists, which is poor form to put it politely. In even poorer form, they then went and damaged the delicate fossil by making casts of it, despite it being in no fit state to be handled that way. Then Teuku Jacob, the lead Indonesian archaeologist, dropped a bombshell: in his opinion the hobbit was nothing more than a modern human with microcephaly. This was quickly dismissed by the original team, who were positive the individual was not a modern human with any kind of pathology, the differences were just too vast. After being granted their fossil back, they set about ordering a full study into the microcephaly hypothesis; which proved, once and for all, that the hobbit did not have the disorder. The team still couldn’t fully celebrate their discovery though, as other scientists weren’t ready to let go of the idea these were humans with a pathology just yet. They suggested the specimens had everything from Down syndrome to endemic cretinism, until, eventually, these hypotheses were thoroughly debunked as well. It seems the biggest error the team made was in their dating, the fossils were from an individual who lived 50,000 years ago, not 12,000.
All evidence now points towards the discovery of a new species: Homo Floresiensis. This is further supported by the fact that even smaller, more primitive, hobbit remains were found in 2014, which were over 700,000 years old. The earliest human fossils yet to be uncovered on Flores. There doesn’t seem to be any good evidence to support the idea that any, let alone all, of these fossils were modern humans with a genetic condition. So, who were they? Where did the tiny people of Flores come from?
A dental study, along with the careful examination hundreds of sophisticated stone tools found throughout the island, seemed to indicate the rapid evolution, towards insular dwarfism, of a H. Erectus population; that became isolated on the island about a million years ago. However, morphological and phylogenetic studies have now placed the hobbit as being a close cousin of H. Habilis. Stone tools found in China also bear more resemblance to those made by the hobbits, than the hobbits’ tools do to those of H. Erectus. This all supports a hitherto unknown human migration out of Africa, prior to that of H. Erectus, by a common ancestor shared by H. Habilis and H. Floresiensis. Which makes the question the original archaeologists set out to answer…how did humans get to Flores in the first place? Even more pertinent today than it was then. Whatever the answer, the dig team has been vindicated. Now, the greatest controversy around the fossils is not if they are a new flavour human, but what flavour of human they are exactly.
And there could possibly be many more flavours of tiny human out there! Only 2 months ago, another specimen, also from an island in south-east Asia, was described. Except, this one lived over 2,800 miles away in Luzon, the Philippines. The teeth and metatarsal were different enough from the hobbits for the archaeologists to claim yet another new species of human had been discovered: Homo Luzonensis. If humans were able to colonise several of the islands in this corner of the world, it’s possible there’s many more new species out there, waiting to be discovered!
This article is part of a series about evolution on islands, other articles in this series:
Giants, Dwarves and Flightless Birds (an overview of evolution islands)
The Horror of Hateg (examines the ecology of Hateg Island from the late Cretaceous)
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