For many decades, conventional wisdom held that the ability to construct complex sea-going vessels did not develop until the last legs of prehistory, in the lead-up to agriculture and more complex societies. Hunter-gatherers were thought to be “reluctant seafarers” if they went at all, and if travel overwater did occur, it was mostly likely by hapless castaways, set adrift by misfortune. There were always archaeological finds from certain locations inaccessible save by long sea voyages—yet the paradigm was believed anyway, buoyed by convention and an element of prejudice against ancient peoples assumed to be little more than savages. This paradigm, however, is now crumbling, worn away by the waves of new discoveries and experimentation. 

It has become an indisputable fact that ancient artifacts from humans or pre-human hominids are found even on very remote islands. Some of the earliest such evidence currently available to us comes from the isle of Flores, in the Lesser Sundas chain of the Indonesian archipelago. This remote landmass had already been settled by archaic hominids over 800,000 years ago, whose probable descendants would eventually give rise to the diminutive Homo floresiensis of the late Ice Age, the “Flores Hobbit.” Flores would have been cut off from the mainland even during the periods of lowest sea levels in the deep Ice Age, with the necessary sea voyage at all times no less than nineteen kilometres of open ocean, even to the nearest islands in the same chain. 

The straits that separate the Lesser Sundas from Bali and Java are deep, and powerful ocean currents run through them: so significant is this barrier that it has contributed to the development of what is termed the Wallace Line, a biogeographical boundary that divides the floras and faunas of Australasia in the south from the Asian ecosystems to the north. Currents might be more favourable if one approached from the north-east, through Borneo and the island of Sulawesi, and intriguingly, recent findings indicate archaic hominid settlement there reaching back over a million years. Even the approach to Sulawesi itself, however, would have been a substantial feat of seafaring needing explanation. In all, then, it is not remotely clear by what route the ancestors of the Flores “Hobbits” reached their island home, nor—crucially—by what means. Reach it, however, they did.

In the Mediterranean, pre-Homo sapiens hominids similarly seem to have made the crossings to isolated islands. On Crete, there is evidence of habitation going back 130,000 years, to, debatably, upwards of 700,000 years. The Cyclades islands north of Crete also contain sites dating to around 250,000 years ago. During the depths of the Ice Age, islands such as Naxos, Delos, and Paros were all united into a single, greater landmass. This large island was home to endemic dwarf elephants and other creatures since lost, yet at all times, the sea-crossing from the Aegean mainland would have been at least fifteen kilometres.

The artifacts from Middle and Late Pleistocene Crete resemble those made by H. Erectus and the preceding H. heidelbergensis elsewhere, while those found on other islands in the region indicate probable Neanderthal settlement. The ancient Mediterranean, it appears, was lapped by many distinct waves of seaborne colonisation, each carrying different species and subspecies of ancient humans.

Perhaps most striking evidence of all comes from the island of Socotra in the Indian Ocean, a strange and remote place sundered from Arabia and the Horn of Africa by wide spans of water and vast gulfs of time. Here, archaeological evidence indicates a settlement by very archaic hominids already between 1.4-2.5 million years ago, which would be by far the oldest such overseas colonisation known.

Summarizing, then, there is ample evidence that our ancestors and their relatives were engaged in frequent and, at times, long voyages over water, even hundreds of thousands of years before the advent of our own species. What is less clear, as alluded to already, is how precisely these travels took place. We know nothing about the nautical technologies of our pre-human ancestors, as indeed we know precious little of our earliest human ancestors and their means, either. Colonisation over substantial distances of water can happen without intent or complex methods: elephants, for instance, have repeatedly succeeded in colonising even relatively far-flung islands. Models have suggested that places such as Sulawesi could perhaps have been reached through successful drift voyages. The sheer frequency with which early humans accomplished such feats, however, does indicate more than mere chance and fortunate buoyancy.

To test the necessary prerequisites for such archaic crossings through real experimentation, Austrian prehistorian Robert G. Bednarik began the ambitious First Mariners Project in 1996: over the following years, his team constructed eight ocean-going vessels, six in Indonesia and two in Morocco. The Nale Tasih 3, a 11.4-meter bamboo raft, was constructed to attempt the crossing from Bali to the Lesser Sundas in 1999. It made it within fifteen kilometres of the isle of Lombok before strong transverse currents forced it back. A second voyage on a second vessel, the Nale Tasih 4, was attempted the following year, now propelled by twelve oarsmen instead of six. This crossing actually succeeded, reaching its intended shore, but only narrowly and after a long, hard voyage through high and choppy seas: so serious was the impact on the crew that upon reaching land, the oarsmen were plagued by severe fatigue and one fell into a coma. 

Four years later, in 2004, another voyage was conducted, this time in a vessel named the Rangki Papa. It was intended to bring ten people from the island of Sumbawa to Komodo, which would have been connected to Flores during the low sea levels of the Pleistocene. The strait between Sumbawa and Komodo is narrow, but even so, the crossing of the Rangki Papa failed. The crew and vessel “performed superbly,” per report, and weather conditions were calm and favourable, yet the currents in the strait proved so strong that the crew were forced south, out into the open ocean. Further voyages were conducted, some successful, others not, but all pointed towards the same conclusion: even with a trained crew on a skilfully constructed vessel, these crossings were difficult and perilous. The odds of successfully accomplishing them merely by chance seem very slim indeed.

If the gradual and sporadic nature of the pre-Homo sapiens island settlements still leaves some room for suspecting an accidental, drift-based explanation, such doubts essentially vanish once our direct ancestors enter the scene. Humans seem to have made the jump—itself a sizable one—from the Indonesian isles to Australia and New Guinea about 50,000 years ago: already by 40 millennia ago, they had continued onwards to New Britain and the Bismarck archipelago, then southeast into the Solomon Isles. By circa 37,000 years ago, people were dwelling on Buka island in the Solomons, and by 28,000 years ago, they had reached the Admiralty Islands to the north of Papua. 

The rapidity with which this movement progressed indicates, almost without doubt, a wilful drive, by a moving front of pioneers both capable of, and willing to, cross substantial spans of water. That these were controlled and intentional settlements is evidenced not merely by chronology, but through other lines of evidence, notably zoological: the northern common cuscus, Phalanger orientalis, a small marsupial often hunted in the region, appears to have been introduced to the Bismarck islands by humans already 20,000 years ago, while other animals such as pademelons (another marsupial) and even cassowaries likewise seem to have been transported around in prehistoric times, evidently as food resources.

Another indirect but strong piece of animal evidence comes to us from the Jerimalai Cave on the island of Timor. There, human refuse from 42,000 years ago contains the remains of tuna, sharks, and other fast-swimming, deep-water fish, the catching of which is practically impossible without purposeful open-sea fishing. A fish hook, made from a mollusc shell, was also found and dated to 23,000 years ago—the oldest definitive evidence of line fishing. Along the Ryukyu Island arc, south of Japan, evidence of human settlement suddenly appears between circa 35,000 to 27,500 years ago on six islands across the archipelago. 

The Ryukyus are separated from the nearest landmass, Taiwan, by a deep, 110-km-wide strait, through which courses one of the strongest ocean currents in the world, the Kuroshio. Consequently, colonisation would have been no little feat. In 2019, a team of researchers reconstructed a primitive vessel and attempted to perform the voyage, similar to the experiments by the First Mariners Project. Unlike the latter project, their oceangoing craft was an archaic form of dugout canoe, not a raft, and the team successfully crossed the strait to Yonaguni Island, the westernmost of the Ryukyus. 

The pattern of these and many other data points is by now clear, the general conclusion self-evident. Why, then, has an acknowledgement of the nautical abilities of early Man been so controversial for so long? As noted, one less academic reason for this reticence has long been a straightforward sort of prejudice. Seafaring, boat-construction, and the associated skills are all signs of varying degrees of sophistication, contradicting the conventional notion that Palaeolithic humans—let alone earlier hominids—were simply too unintelligent to perform such feats. 

There are other factors, however, and most significant among them is this: the oldest preserved boats in the world are no more than 10,000 years old, and these are from only a minute number of sites. Strong indirect evidence comes in the form of ancient paddles discovered in Stone Age deposits, yet none of these date further back either. Aside from the aforementioned fish hooks, no archaeological evidence of major nautical technologies whatsoever exists from the long millennia of the Ice Age.

While absence of evidence is not, as a rule, evidence of absence, it is also not the contrary; archaeologists are, by nature, a conservative breed, and rarely feel comfortable speculating far beyond the direct line of evidence. Experimental research of the sort described above is one opening into this lost past—reconstructing, if not what we know our ancient ancestors did build, then at least the sort of vessels they might have constructed, using the available tools and resources. Modern ethnographic evidence, as well as cross-continental archaeological surveys of the more recent past, likewise offers us indications of the variety and ubiquity of seagoing technologies across time and space. None of them, however, bring us into contact with the thing itself, the actual lost artifacts. Quite plausibly, nothing ever will.

There exists in palaeontology a principle termed the Lipps-Signor Effect, which states that, owing to the paucity of fossils and factors of preservation, it is highly unlikely that our available remains represent either the first or last specimens of any given species. That is, there is almost inescapably some discrepancy of time, perhaps a fairly major one, between where our fossils begin and end, and where the actual species did. A similar archaeological effect is clearly at work here. 

Add to this a second key factor, which is that of location. The most likely place for a boat to be preserved is naturally by the waterside, especially the coast, and owing to post-glacial sea level rises, any such site more than eight to ten thousand years old is now most likely drowned under many metres of water. The surviving sites we have from the deep Stone Age are overwhelmingly inland sites, and this inevitably introduces a very substantial bias against any sorts of watercrafts or assorted nautical miscellanea being preserved, even apart from the basic reality that large wooden objects simply tend not to endure long.

Looking back at this whole exploration, what, then, can we truly say in summary? On the one hand, frustratingly little: irrefutable evidence of settlement and movement is paired with a total blindness as to the actual means and process. Did the voyagers of the Stone Age seas employ rafts or dugout canoes? Were they limited to rudimentary floats? Did they invent outriggers or sewn hulls? Did the notion of a primitive sail ever occur to any Palaeolithic mind, even if such technology evidently did not survive for long? 

Prehistory is vast and the world wide. It is quite possible that different crafts and technologies were used by different peoples at different times; there is no good reason to suppose that the archaic Australians of 40,000 BC would necessarily have boated like the Iberians of 25,000 BC. Technologies may have been invented, and flourished, for hundreds or even thousands of years before being lost and entirely forgotten—or, the Stone Age world may simply have been a more primitive, unchanging one in this regard, restricted to only the most basic of seacrafts. We do not know; we cannot know. Yet what we do have is a glimpse of a wide horizon for early Man, one stretching over both land and sea. From high mountains to distant isles, there was more to our earliest ancestors than we have hitherto given them credit for.