Authors: Chris Stringer
The authors of the original studies suggested that
H. floresiensis
might be a descendant of
H. erectus
that had arrived earlier on Flores, perhaps using boats. This idea was partly inspired by the existence of stone tools on the island that were at least 800,000 years old. They argued that the species then evolved a very small size under isolated conditionsâa phenomenon known to occur in island populations of other medium-large-sized mammals and called
island dwarfing
. If the ancestors of
H. floresiensis
really made watercraft to reach the island, this would be surprising, because such behavior is usually considered to be exclusive to our species. (Even the Neanderthals were seemingly unable to cross the English Channel from France about 120,000 years ago, or reach the islands of the Mediterranean, with the possible exception of Crete.) However, the alternative of accidental rafting on mats of vegetation must also be considered; the Asian tsunami of 2004 dispersed people on rafts of vegetation for over 150 kilometers, reminding us that this is a feasible process in a geologically active area like Indonesia. Moreover, studies of the prevailing ocean currents suggest that the ultimate origin of the Hobbit may not have been from Java to the west, but from Sulawesi to the north. Mike Morwood's follow-up work in Sulawesi lends support to this idea, since stone tools that could be at least 1 million years old have also been found there, although sadly so far without accompanying fossils.
Further studies provided more detailed information on the limb bones of
H. floresiensis
, both from the original skeleton and from other individuals, all of them very small, and some dating as far back as 95,000 years. A second jawbone, similar in its primitive and distinctive features (for example, its lack of chin, thick body, and divergent tooth rows) to the one associated with the original skeleton, was described by the anthropologist Peter Brown. Puzzlingly for a supposed human species, the body proportions, wrist bones, hip bones, and shape and robustness of the arms and legs of
H. floresiensis
are in some ways more similar to fossils of prehuman African species like
Australopithecus afarensis
(the most famous example of which is “Lucy”) and the newly discovered
Australopithecus sediba
(from South Africa) than to later humans. In addition, unusual features of the shoulder joint have been reported, as well as the fact that
H. floresiensis
seems to have had large flat feet! While these peculiar features have fueled speculation that the remains are abnormal, other workers have argued that they show evidence for an unusual evolutionary trajectory, in island isolation. In the case of the wrist, the shape of these bones in two different adult individuals resembles much more closely those of apes and
afarensis
than of recent humans such as Neanderthals and usâand these are bones whose shapes are already mapped out before birth. The likelihood that a pathology in two different individuals could independently convert wrist bones back to a similar primitive-looking condition seems remote indeed.
Further uncertainty surrounds the evidence of humanlike behavior excavated from Liang Bua. Some of the stone tools are delicately shaped, and there is possible evidence of burning (although perhaps naturally produced) and of predation on young
Stegodon
. I'm still not convinced that
H. floresiensis
, with its ape-sized brain, was capable of such behaviors, and in my view we need further evidence and analyses to exclude the possibility that early modern humans were also using caves on Flores before 18,000 years ago and could be responsible for some of the later archaeological evidence left behindâalthough this is unlikely to be so in the deepest levels of the cave. If
H. floresiensis
is indeed genuine and distinct, rather than abnormal (and I think the evidence is growing strongly in its favor), there are the intriguing questions not only of where it came from (Java to the west or, as Morwood now believes, Sulawesi to the north?) and how it got there, but of what happened to it, and whether our species encountered these diminutive relatives. Perhaps volcanic eruptions or climatic change around 17,000 years ago affected its habitat, or perhaps modern humans killed it off directly, or by consuming the resources on which it lived. In which case, an even stranger encounter than the one between the Neanderthals and modern humans was played out at an even later date, on the opposite edge of the inhabited world. But against that possibility is the evidence that there may instead have been a period of several thousand years with no one on Flores, following the extinction of the Hobbit, before modern humans finally arrived after 12,000 years ago.
The Hobbit remains a perplexing find for all of us, whatever our evolutionary viewsâwitness my own problems in coming to terms with the possibility that its chimp-sized brain could be associated with “human” behavioral complexity. But it has proved most difficult for some scientists of multiregional persuasion who are wedded to the idea that there can only have been one human speciesâ
Homo sapiens
âin existence over the last 2 million years or so. Rather than contemplate a painful divorce from cherished beliefs, they have preferred to argue that the Hobbit represents the “village idiot” of a modern human communityâor even more remarkably, that it's a recently buried oddity, as shown by the presence of dental fillings (there is no evidence that the Hobbit was ever seen by a dentist!). In the short term these researchers have raised their profiles by courting controversy, but in the longer term, I think they have damaged their own, and paleoanthropology's, reputation.
As we saw, under Out of Africa 1, most experts consider that
H. erectus
was the first humanlike creature to emerge from the ancestral African homeland, nearly 2 million years ago. But for some researchers, the Flores material raises the possibility that more primitive, perhaps even prehuman, forms had previously spread from Africa across southern Asia, where the remoteness of Flores allowed them to survive and evolve along their own peculiar path, in isolation. And the evidence from Dmanisi is now being added to this rethink, since the lack of very ancient fossil human evidence from Asia, apart from Dmanisi, is considered by archaeologists like Robin Dennell and Wil Roebroeks to reflect a lack of preservation and discovery, rather than a real absence. Combining the primitiveness of the Dmanisi specimens and tools with a similar view of the Liang Bua finds, it is argued that there was a widespread phase of human evolution in Eurasia about 2 million years ago, which is now only represented by the isolated Dmanisi and Hobbit fossils. This alternative scenario has a small-brained and small-bodied pre-
erectus
species, perhaps comparable to
Homo habilis
or even a late australopithecine, dispersing from Africa with primitive tools over 2 million years ago, reaching the Far East and, eventually, Flores. In Asia, this ancestral species also gave rise to the Dmanisi people and
Homo erectus
, while Dmanisi-like people reentered Africa about 1.8 million years ago and evolved into later populations thereâincluding, eventually,
Homo sapiens
. So the orthodoxy of Out of Africa 1 is being challenged because of new evidence, and new interpretations of old evidence. And the same process of reevaluation is happening with Out of Africa 2, as we shall see next.
Views on the origin of our species have gone through many formulations and reformulations since Darwin laid out his expectations of what the evidence would provide, but an African origin for
Homo sapiens
is now the mainstream view. I explained earlier how finds like those from Dmanisi and Flores have threatened the scenario known as Out of Africa 1, and we will now look at new evidence from Europe, Africa, and Asia that is changing ideas about the more recent parts of our evolutionary story. These finds include the remarkable 160,000-year-old Herto skulls from Ethiopia (some of the oldest and most massive individuals of our species ever discovered), the 40,000-year-old fossils found by cavers deep in an underground chamber in Romania that may show hybridization between modern humans and Neanderthals, and the oldest
sapiens
fossils from China, whose feet hold clues to a vital modern innovation. In the last few years we have also learned a lot about our Neanderthal cousins: where they came from, how they behaved, how their bodies worked, and even (as I explain later) how their whole genetic code compares with ours. But now I'm going to highlight some of the most interesting fossil finds of Neanderthals from the last twenty years, before going on to discuss the evidence of other peoples who may have been closer to our evolutionary origins.
Asturias, just south of the Bay of Biscay, is one of the less fashionable provinces of Spain. But like much of the Iberian peninsula, right down to its southern tips in Portugal and Gibraltar, Asturias was a favored territory for the Neanderthals. In 1994 some explorers were probing the depths of the large and still partly unexplored El Sidrón network of caves, hidden among densely forested hills, when they discovered two human jawbones lying in the cave sediments. Because partisans were known to have hidden in the cave during the Spanish Civil War, the police were notified in case the remains were recent, and over a hundred further bones were soon discovered. Forensic investigations over several years showed that the bones were fossilized, not recent, and were in fact those of Neanderthals who had died over 40,000 years ago. The area where the bones were found has been named GalerÃa del Osarioâ“tunnel of the bones”âand about 1,500 bone fragments from some twelve Neanderthals have now been unearthed there. At first glance it seems like an extended family was represented, since there are adults, teenagers, and children, but this was no happy domestic scene, at least not in the fate that seems to have befallen them. Their bones and teeth suggest they were reasonably healthy, although there are signs of growth disturbances during early and late childhood in the teeth.
However, the state of the fossilized bones shows that these individuals may have died violent deaths: they displayed many cut marks, especially one jawbone and the children's skulls, and they may have been pounded and smashed with great force, using stone tools or rocks, apparently to extract the nutritious brain and marrow. So this seems to be evidence, and by no means the first, of cannibalism among Neanderthals. Other examples are known from places like Croatia (Vindija) and France (Marillac and Moula-Guercy), and seem to reinforce stereotypes of the Neanderthals as savage subhumans.
Oblique view of the most complete 160,000-year-old Herto
Homo sapiens
skull from Ethiopia.
Side view of the Herto 1 skull.
The child's skull from Herto.
Yet cannibalism seems to have been a regular enough part of human behavior over the last million years or so for it to be represented in many fossil assemblages, and so it might almost be considered as “normal” for early humans, however distasteful (in every sense!) we might find it today. It appears to be present in the
Homo antecessor
(“Pioneer Man”) remains at Atapuerca about 800,000 years ago, which are cut-marked and smashed like the Sidrón fossils, and which lie alongside butchered animal bones. It may also have been present in
Homo heidelbergensis
âat Bodo in Ethiopia about 600,000 years ago (although here it's mainly evident from cut marks on a skull suggesting the eyeballs had been removed), and at Boxgrove in Sussex, where I explained that two isolated front teeth seem to have been forcefully wrenched from their jawbone (now lost). Its antiquity may even stretch back to the very first humans. The cheekbone of a 2-million-year-old fossil skull from Sterkfontein (South Africa), often assigned to the very early human species
Homo habilis
(“Handy Man”), shows signs of having been cut during the slicing apart of the jawbone from the skull, and this too may have been for consumption. And we should not let our own species off the hook either, since 80,000-year-old bones from Klasies River Mouth Caves in South Africa, and 14,700-year-old bones that I helped to excavate from Gough's Cave in Somerset, also show the telltale signs of butchery. Unfortunately, there is also enough sound evidence beyond the exaggerations in traveler's tales to indicate that butchery and consumption of human flesh have occurred in the very recent human past.