The following is an excerpt from chapter 19 of Ancient Bones: Unearthing the Astonishing New Story of How We Became Human by Madelaine Böhme, Rudiger Braun and Florian Brier.
Wanderlust: Curiosity About the Unknown
Are curiosity and the desire to settle new areas the characteristics that set the first modern humans apart? Or do they belong to the millions of years it took to make us? Only about one-fifth of the Earth’s surface remains undisturbed enough today to be called something approaching “wilderness.” We have left our mark on the rest of it in one way or another. People have settled almost every corner of the Earth, even areas that are hard to reach, with the exception of Antarctica. And they did this earlier than previously thought.
For a long time, we believed that our ancestors reached remote islands far out in the ocean just a few tens of thousands of years ago at the earliest. Only the anatomically modern Homo sapiens with its big brain would have had the technology and intellect to be able to build boats and navigate the oceans. Or, at least, that is what we thought. We did not think earlier species of human would have been able to complete such a culturally complex task. At first, archeological finds seemed to confirm this assumption. The oldest boat in the world—a dugout canoe from Mesolithic times—is about ten thousand years old. It was probably used only on small patches of open water in the fenlands and was certainly not seaworthy.
There has been a series of finds in Asia, however, that shattered the idea that Homo sapiens was the first seafarer and explorer in this world. Those finds suggest it is far more likely that the ability to cross oceans goes back more than a million years to the early members of the species Homo. The best-known of them was made on the Indonesian island of Flores in 2003. This early species of Homo became world famous under its nickname, the Hobbit. Homo floresiensis—its scientific name—was not only a hither-to-unknown species of human, but also one that did not fit with any of the prevailing theories of human evolution. For me, that was reason enough to get a better picture of this puzzling hominin for myself, and so, in the spring of 2015, I traveled to Indonesia just as the rainy season was drawing to a close.
Visiting a Real-Life Hobbit
Flores, a volcanic island thrust up in one of the most tectonically active regions of the world, lies just 8 degrees south of the equator. Here, the Australian continental plate is being pushed under the southeastern-most tip of the Eurasian continental plate at a speed of about 2.5 inches per year, thrusting up a massive island chain in South Indonesia that stretches for many thousands of miles.
The combination of volcanoes and weather leads to a mixture of very different types of landscapes. Thick tropical forests alternate with small open savannah areas where the only shade to be found is beneath a few scattered palms. These habitats on the west side of the island are where the 10-foot-long (3-meter) Komodo dragon lives to this day. A species of monitor lizard, it is the largest lizard on Earth and powerful enough to take down a buffalo. It is named after the small island of Komodo, which lies to the west of Flores, but its range is not restricted to that island. It is worth the journey just to meet one of these “living fossils.”
The main attraction on Flores for me, however, was the Liang-Bua Cave, the site where the Hobbit was found. The cave lies in the interior of the island and can be reached only by a car journey that is not for the faint of heart. The network of roads on the island is not well developed. On the few paved sections, pickups race past each other, focused on just one goal: delivering fresh fish from the coast as quickly as possible.
Everything changes, however, the moment you leave the main thoroughfares. The only option here is to drive slowly over bumpy dirt roads. This gave me plenty of time to observe the fascinating landscape of Flores. For the most part, the countryside has retained its original rural character, and only a few places have any tourism to speak of. What impressed me most were the symmetrical spider webs of lush green rice fields nestled in the hilly landscape, a sight you can see only on Flores. They are a testament to a long tradition of cultivating rice in a way that is unique to the island.
After we had been on the road for about three hours, the frequency of hairpin bends increased dramatically as the narrow road wound its way for another 30 miles (50 kilometers) up a long chain of volcanic mountains, where the highest peak reaches an elevation of nearly 8,000 feet (about 2,400 meters). These high ridges are remarkable for an island that is little more than 3 million years old. Thanks to plate tectonics and volcanic activity, even today Flores is rising by about 0.02 inches (half a millimeter) a year.
At the northernmost slope of the mountain chain, we arrived at a heavily forested limestone massif. The unpaved tracks in this area were still muddy from the recent rains. About 100 yards (100 meters) down the slope, the primeval forest river Wae Racang cuts into the rocky ground. There is nothing in this landscape but small remote villages. Even at a distance, the betel palms give them away, towering up over the vegetation like cell-tower antennae.
After a journey that had lasted at least four hours, my traveling companions and I finally crossed a narrow metal bridge over the Wae Racang. Three hundred yards farther on, we stopped in front of an unassuming wood cabin with a sign that read “Museum Mini Liang Bua.” It was not clear to me whether this was a museum about a small person or whether it was referring to the size of the building. There was no time, however, to sort this out, as the museum director, Kornelius Jaman, was waiting for us at the entrance. Jaman had participated in almost all the digs at the Liang Bua Cave since 2001, and when no digs were underway, he gave visitors tours of both the museum and the cave in which he shared his passion for all that they had found.
On the slope directly behind the museum, barely 130 feet above the Wae Racang, the 82-foot-high mouth of the cave opens up majestically in the rock face. Massive stalactites festoon the edges of the opening like the fringe on a tablecloth. The inside of the cave is even more impressive. Barely 130 feet deep, it is a bell-shaped limestone cathedral flooded with bright green light from the primeval forest outside. Moss and algae grow on the stalactites, and the even dirt floor of the cave is a brownish color. When we were there, Jaman pointed to a rectangular depression in the ground, the very spot where, in 2003, LB1, the skeleton of Homo floresiensis was found 20 feet down. After the researchers stumbled across the fossils, it quickly became clear that nothing like them had ever been unearthed before. The find triggered a debate that continues to this day about where the Hobbit belongs in the story of human evolution.
To get a general picture of the debate and to answer the question about the significance of Homo floresiensis, let’s first look at the anatomical peculiarities of the fossils and then review the unique paleo-environment of Flores at the time the Hobbit lived there.
The skeleton LB1 belongs to a female. She was about 3 feet 6 inches (1.06 meters) tall and weighed about 66 pounds (30 kilograms), which makes her about the same height and weight as Lucy in East Africa and Udo in the Allgäu. LB1 also shared her small brain size of about 400 cubic centimeters with early hominins and chimpanzees. Other features of the skeleton indicate an early stage of evolution as well. The pelvis and wrist are similar to Lucy’s, and there is some evidence that the arch in the Hobbit’s foot had not yet formed, another feature that points to a very early stage of human development. Moreover, the bones on the top of the skull are considerably thicker than those of modern humans. The same could be said for the build of the shoulders, which look most like those of Homo erectus. The Hobbit’s arms are even longer than those of other early hominins and early humans, which makes it seem more apelike.
Homo floresiensis had especially large feet, which was rather fitting, given its nickname. The Hobbit’s feet are, amazingly, 70 percent as long as its thigh. To put that in perspective, modern humans’ feet are half as long as our thighs. A Homo floresiensis that stood 5 feet 7 inches tall would have had feet that were 12.6 inches long. That corresponds with a size 16 (European size 50) in shoes. People who wear shoes this large today are usually over 6 feet tall. With feet this size, Homo floresiensis must have had to lift its legs higher than we do when it walked, and it could certainly not run nearly as fast as modern humans. Yet, if you look at its teeth, tooth roots, and jaw shape, there are similarities once again with Australopithecus and other primitive early humans, such as those found at the world-renowned site of Dmanisi in Georgia that are still revealing their secrets today. All in all, the Hobbit appears to be a mosaic of numerous other finds from Africa and Eurasia.
Because scientists could not explain this strange mixture of features, it was not long before someone proposed that Homo floresiensis was a modern human anatomically affected by disease. Those who supported this idea argued that numerous, often hereditary diseases lead to small stature, small brain size, and deformed bones in modern humans, and so surely some earlier human species had also been affected by these. The estimated age of the find initially supported this theory. At first, the scientists who discovered the Hobbit dated its age to 18,000 years ago, a time at which Flores had long been inhabited by modern humans. Also, along with the bones, the researchers had found stone tools and evidence of the use of fire, both cultural skills that are associated only with more highly developed forms of human—and which stood in contrast to the small brain size of Homo floresiensis. And finally, this opinion also fit with the assumption that primitive early humans would not have been able to cross the ocean to Flores, which remained an island even at the height of the last ice age when the sea level was 395 feet lower than it is today.
In 2016, however, it was discovered that the original dig team had overlooked an important geological marker in the cave deposits: a 50,000-year-old area of erosion that angled through the deposits. It proved that the layer in which the skeleton was embedded had been freed at that time through natural processes and then re-covered with sediment. This process also explained why the stone tools and charcoal remains ended up at the same level as the bones of the Hobbit. The researchers took a closer look at LB1. They also analyzed the fossils of 14 more Hobbits that had been unearthed during new digs in Liang Bua since 2003. They found that all the fossils of Homo floresiensis from this cave were between 50,000 and 195,000 years old. The Hobbit could not therefore be the remains of modern humans who had been stunted and misshapen by disease, because Homo sapiens first arrived on the island 46,000 years ago.
There was a wealth of other important arguments against the idea that LB1 was a modern human deformed by disease. It is as good as impossible that in the span of the 150,000 years the species Homo floresiensis inhabited the cave it just so happened that only the bones of diseased individuals remained. In addition, in 2014, 50 miles) away in the So’a Basin in Central Flores in a dig outside the confines of a cave, the skeletal remains of three more individuals that resembled Homo floresiensis were unearthed and were dated back even further, to 700,000 years ago. These fossils were even smaller than those found in the Hobbit cave. It seems that these early humans were once 2 feet 7 inches tall. Researchers also found stone tools at the site that were more than 1 million years old. That means Flores must have been settled by very small humans more than a million years ago.
These were the thoughts that were going through my head when Jaman finally led us into his museum after our tour of the cave. There, in a glass display case, lay the skeleton of LB1 in all its glory. Even though the skeleton on display was a copy (the original is in Jakarta), I still stood in awe when faced with this fascinating testament to human evolution. Jaman gave us a detailed description of unearthing each and every bone and of the problems the dig team faced. The bones buried in the wet floor of the cave were very damp, easily damaged, and soft as butter. The glues and rock hardeners they applied as the bones were unearthed were not intended for use on damp material and many of the bones were damaged. Photographs on display showed how the fossils were laid out to dry on newspaper on a bed in a hotel room.
Of Dwarf Elephants and Giant Rats
If the Hobbit was not a sickly undersized modern human, what could it be? Other finds from the cave provided helpful clues, and Jaman has the original bones from some of them safely stored in his museum. The researchers in Liang Bua also found the remains of elephants, birds, reptiles, and rats. What is astonishing is that all these fossils are either unusually small or especially large. Take elephants from the genus Stegodon, which were distributed across large areas of Asia at the time. The examples from Liang Bua were only 5 feet tall at the shoulder, tiny in comparison with conventional stegodons, which were about the size of African elephants. The birds, reptiles, and rats in the cave, however, were gigantic.
The researchers dug out the bones of a marabou stork that stood nearly 6 feet tall. Today marabou storks are no taller than 5 feet. The extinct Flores marabou stork also had thicker and heavier bones, which means it would have been incapable of flight. Even the bones of Komodo dragons excavated from the cave were up to 50 percent larger than the largest modern specimens. Three species of the fossil rats that were dug up were veritable giants. Apart from the Hobbit and the elephants, the rats were the only mammals found at the site. The largest was the Flores giant rat, which is still found on the island today and measures 30 inches from its nose to the tip of its tail. People who are native to the island value them for their meat, just as their ancestors did. After the tour, Jaman invited me to his home close by, where I could taste them for myself.
So, the picture you get of Flores when the Hobbit lived there is somewhat hazy. Only a few vertebrates lived on the island and, compared with their closest relatives on the mainland of Asia, they were either very small, like the human and the elephant, or unusually large, like the marabou stork, the lizard, and the rat. How had this bizarre animal world arisen? The ocean around Flores is so deep that the only way animals could have reached the island is by sea. However, Flores lies in the middle of what is known as the Indonesian throughflow and is surrounded by the strongest ocean currents in the world. The Indonesian throughflow is one of the central components of the global climate system, a sort of gigantic heat pump that transports 530 million cubic feet of warm Pacific water per second past Flores and into the cooler Indian Ocean—that is, 4 billion gallons. Yet, all the species of animals found on Flores are ocean migrants. They originally came from the western part of Indonesia—the elephants, the stork, the rats—or from Australia—the monitor lizard.
It was easiest for the birds, because they could fly to the island. The stegodons must have swum across. Smaller mammals such as rats could have arrived on driftwood, which often builds up after storms. After they arrived on the island, the animals must have adapted to their new, remote habitat. The larger species, such as the elephants, got smaller, which allowed them to survive with less food and at the same time sustain a large enough population to maintain genetic diversity. A smaller population of elephants of a normal size would likely have led to inbreeding, which over time would have meant the demise of the species.
In contrast, meat- or carrion-eating animals, such as the monitor lizard or the marabou stork, faced no competition for food on Flores. In other ecosystems, cats or hyenas could have fought them for prey or carcasses. On Flores, however, the marabou storks clearly did not even have to fly to find enough to eat. They grew bigger and gave up flying altogether. The lizards, too, must have felt right at home. All they needed to do was grow bigger than they already were and they could hunt even the dwarf elephants. Life was probably particularly easy for the adaptable, omnivorous rats. They found plenty of food both on the ground and up in the trees—ideal conditions under which to grow large, very large. Even given huge distances and extreme conditions, like the ones around Flores, it seems that the arrival of land animals to colonize remote islands was not uncommon.
Hobbits on the High Seas?
People, however, are anything but accomplished swimmers and cannot fly. Add to that the fact that a remote island can- not be settled over the long term—in the case of the Hobbits for more than a million years—by a handful of individuals. If inbreeding is to be avoided, a certain population level must be maintained from the outset.33 Every successful and long-lasting colonization of an island by people, therefore, is a noteworthy cultural act that requires conscious decision making, organized activities, and a basic understanding of human biology. Which members of the group should make the journey? Experienced older people or younger people of a reproductive age? How many men and how many women are needed to settle the new environment successfully? How many tools and how much in the way of provisions do you pack when you are making a journey into the unknown? What would be simply a logistical challenge today—you only have to think of plans for colonizing the moon or Mars—would have been an almost inconceivable undertaking and would have required a complex language for meaningful communication. This, incidentally, is one reason why I believe we need to rethink our ideas about such early human cultures.
Certainly, when many of us think about how these ocean crossings might have been made, we conjure up images of technologies such as boats or rafts. But there are other ways and means of getting to islands, and there is evidence that they were used. In the 1980s, the Dutch paleontologist Paul Sondaar pointed out that elephants had a “snorkel” and that there might be a strong connection between the settlement of many islands by elephants and their settlement by people. When an elephant swims, most of its body is submerged. Only the back of its head and, occasionally, a small part of its back is visible above the water, but with its trunk held straight up, it can still breathe. Elephants swim many dozens of miles in this manner. Copperplate engravings made by Dutch travelers in the eighteenth century show the native peoples of the Indonesian islands using swimming elephants as a means of transport to neighboring islands. Standing on the back of his elephant, the mahout takes the reins in his hands and steers his animal across the sea.
The paleontological investigations of Indonesia, in which Sondaar played a hugely important part, showed that over the past 2 million years almost every island was settled either by elephants or by their close relatives, the stegodons. The same holds true for the Mediterranean region. Elephants and people were often the only large mammals that made it to these islands. That made the well-known South African paleoanthropologist Phillip Tobias suspect this had not happened by chance. It is conceivable, for example, that early hominins or early humans noticed elephants purposefully walking down to the beach, swimming out past the horizon, disappearing from view, and never coming back. The animals were perhaps following scent signals or calls from their fellow elephants on remote islands that they were able to detect even over great distances. And so it is possible that early humans sought out the animals and finally managed to cross oceans by riding on their backs. We know from the lifelong relationships that mahouts have with working elephants today that humans and elephants can form strong bonds of trust.
The Origin of the Hobbit
But how do these deliberations help us when it comes to the Hobbit? What if Homo floresiensis was not an island species, after all? Did it really arrive on Flores by chance? Was it small of stature because of limited resources in its new environment? It took a while for scientists to give serious consideration to such questions. Many researchers continued to champion the idea that the Hobbit shrank in size.
According to these scientists, the small Homo floresiensis was directly descended from the large Homo erectus, which lived on Java 1.5 million years ago. A few of these early humans, they argued, somehow made it across the ocean to Flores and shrank, just as the stegodons had done. As evidence for this, they cited the lack of large prey animals on Flores. And, indeed, it is clear that the Hobbit mostly ate giant rats, as we can see from the remains of about two hundred of these rodents in Liang Bua Cave. I might mention here that it is unlikely that rats alone, even giant rats, would have been a sufficient food source for early people as large as Homo erectus. However, the researchers also found a few dwarf elephants in Liang Bua that had been butchered for their meat. They are evidence that once in a while even Hobbits could catch and kill a stegodon. Even in miniaturized form, these elephants weighed up to 880 pounds. Such large quantities of meat could also have fed larger early humans, especially if you consider they could also steal eggs, gather seafood along the coast, and snack on insects.
However, as we have seen, there is little in the Hobbit’s skeleton to suggest that what we are dealing with here is a miniaturized version of Homo erectus. The most recent ancestral study of Homo floresiensis, therefore, breaks with this idea and places the Hobbit close to the origin of the genus Homo. The authors of the study think there are two possible scenarios. In the first one, Hobbits share a common ancestor with Homo habilis, a species that has been proven to have lived at least 1.75 million years ago in Africa. The second puts the Hobbit right at the beginning of the Homo lineage, 2.8 mil- lion to 2 million years ago, a phase of early Homo evolution for which we have very few diagnostically conclusive finds in Africa. This second interpretation is in accord with finds of tools in India and China that have been dated to 2.6 million years ago, and with the almost 2.5-million-year-old “mystery ape” from the Yangtze River, Homo wushanensis. In this latter scenario, Homo floresiensis would not even have been an especially small hominin, because many early hominins and early humans stood no more than 3 feet tall. That is the case for Lucy, for example, and also for whomever left the footprints in Crete. Small stature, up to only 5 feet, is a characteristic of all early hominins. It was only with Homo erectus, 1.7 million years ago, that humans grew to be more than 6 feet (1.7 meters) tall.