Hominins and stone tools in Sunda 1.48 Ma - Implications

A paper published last August in Nature (Hakim, B., Wibowo, U.P., van den Bergh, G.D. et al. Hominins on Sulawesi during the Early Pleistocene. Nature 646, 378–383 (2025). https://doi.org/10.1038/s41586-025-09348-6) reported finding stone tools and flakes older than 1 million years, and possibly up to 1.48 Ma on the island of Sulawesi in Indonesia.

The oldest tools that had been found in the area were found at Wolo Sege on Flores Island, home of the minute Hobbit Homo floresiensis, that were 1.02 million years old. Some stone tools and bones with man-made cut marks were discovered in Luzon, and island in the Pilippines, dated to 777-631 thousand years ago. These are much older.

The paper states that> "The dispersal of archaic hominins beyond mainland Southeast Asia (Sunda) represents the earliest evidence for humans crossing ocean barriers to reach isolated landmasses... On Sulawesi, the largest Wallacean island, previous excavations revealed stone artefacts with a minimum age of 194 ka at the open site of Talepu in the Walanae Depression, long preceding the earliest known presence of modern humans (Homo sapiens) in the region (73–63 ka in Sunda). Here we show that stone artefacts also occur at the nearby site of Calio in fossiliferous layers dated to at least 1.04 Ma and possibly up to 1.48 Ma... The discovery of Early Pleistocene artefacts at Calio suggests that Sulawesi was populated by hominins at around the same time as Flores, if not earlier."

Primitive Stone "artifacts"

The authors found "seven flaked stone artefacts... All stone artefacts are made of chert, alternately known as silicified limestone in some of the related literature. This source material is abundantly present among the naturally occurring pebbles, but the stone artefacts differ statistically by their larger size compared with unmodified pebble-sized clasts excavated from the same fluvial sandstone deposits... These results suggest that the stone artefacts were produced by hominins outside the Calio site and carried there for use as tools, further underlining the anthropogenic origin of these objects. It is also possible that some or all artefacts could have been eroded out of riverbanks by laterally migrating fluvial channels, and may therefore be older than the layers in which they were found."

They are not Acheulean, a mark of H. erectus, these are stones used simple tool-making techniques that hint at an Oldowan origin. However, the stones were carefully struck, and retouched: "The flakes were struck by the hard-hammer freehand percussion technique and range from 21.9 to 60.1 mm long along the percussion axes... The reduction of large flakes into smaller flakes, which were themselves retouched, suggests that a two-step reduction process was sometimes used to reduce the natural chert cobbles into suitably-sized tools. The evidence for reduction of cores-on-flakes, frequent core rotation and understanding of hard-hammer fracture mechanics attests to expert technical knowledge within the context of a straightforward, ‘least effort’ approach to toolmaking.".

The authors conclude that "it now seems possible that hominin occupation of this large Wallacean island preceded that of Luzon to the north and is at least as old as, and potentially earlier than, the hominin presence on Flores to the south. However, precisely when hominins first crossed to Sulawesi remains an open question, as does the taxonomic affinity of the colonizing population."

These people predate the hominins of Luzon and the hobbits of Flores. Their stool-making techniques suggests that they were not H. erectus, could they have been the easternmost members of the group that reached Georgia (Dmanisi people), a branch of H. georgicus?

Sulawesi stone artifacts (Fig. 2) in Hakim, B., Wibowo, U.P., van den Bergh, G.D. et al. (2025)

A 2024 paper (D. Ma,S. Pei,F. Xie,Z. Ye,F. Wang,J. Xu,C. Deng, & I. de la Torre, Earliest Prepared core technology in Eurasia from Nihewan (China): Implications for early human abilities and dispersals in East Asia, Proc. Natl. Acad. Sci. U.S.A. 121 (11) e2313123121, https://doi.org/10.1073/pnas.2313123121, 2024) noted that in Niwehan, in northern China, west of Beijing, stone tools dated to 1.1 million years ago, were Acheulean style (or mode-2 technology - compared to Oldowan or mode-1), despite the lack of the characteristic handaxe that this type of stone knapping produces. They attribute the lack of handaxes to the poor quality of the raw materials used. They find that these tools "at 1.1 Mya now constitutes one of the world’s earliest occurrences of prepared core technologies... This may suggest that mode 2 hominins dispersed into East Asia much earlier than previously thought and, given that the earliest occupation of China could be over 2 Ma, our results may also point at multiple migrations of early hominins into East Asia throughout the early Pleistocene."

The tools, in my layman opinion, seem to be Oldowan. The authors explain that they are Acheulean because they display higher mental abilities required to perform additional steps in knapping, elaborate techniques, and "standardized end products". They admit that "the differences between CJW (and by extension other Nihewan sites) and the typical Acheulean should not be ignored, and the absence of handaxes in East Asian sites cannot be attributed to raw material availability only... we propose that these mode 2 hominins with complex technical abilities were led to produce smaller tools due to the poor local raw material quality and environmental conditions, which may have also required the development of new survival strategies and/or technological innovations to adapt to the local environmental conditions in this region of northern China."

If we accept their explanations, then two (or more) different populations peopled Asia 1.1 Ma, one in Sunda another in China, with different tool-making techniques. This was way before Denisovans, Neanderthals and modern humans. Were they H. erectus? Dmanisi - H. georgicus? Another unknown hominin?

Could any of these groups have moved north and then east, into America? They would have had 1 million years with the New World for themselves before modern humans arrived around 30 ky ago, or perhaps Neanderthals and⁄or Denisovans arrived during the past 500 ky. Who knows? Nobody ever digs deep enough to look for any remains older than 20,000 years in the New World.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2025 by Austin Whittall © 

Homo erectus the sailor seaman

 

Map showing Sahul, Sunda, Wallacea and Flores. Copyright © 2011 by Austin Whittall

Homo erectus the sailor: in previous posts I mentioned that H. erectus could have used watercraft to reach America, but I did not reference the statement. Today we will see what evidence supports the idea of a navigating erectus.

Flores island or crossing Wallace’s line

H. erectus after leaving Africa trekked along South Asia’s coast and reached what is now Indonesia. There he came to a dead end at Bali. The sea blocked any further advances towards the south.

However, a Dutch missionary named Theodor Verhoeven [1], an amateur archeologist who lived on Flores Island, discovered on that island, some man-made stone tools together with the remains of an extinct elephant (the Stegodon) which dated back to over 750,000 years ago. He concluded that the tools were as old as the bones and that the only humans of that period (H. erectus) had made the tools and, much more important, reached Flores Island.

Flores was not linked to the rest of South East Asia at that time, it was isolated by a strait of treacherous deep sea from the other land masses.

This was a formidable barrier, and actually divides the fauna of Asia (monkeys, rhinos, elephants) from that of Australia and New Guinea, confining marsupials to the latter. It is known as Wallace’s line (after biologist Russel Wallace who, independently from Charles Darwin, and at the same time, formulated a theory of evolution based on natural selection).

Animals could only island hop up to Wallace’s line. One one side was "Sundaland", which comprised the mainland and the large Indonesian Islands, which when the sea level was lower, formed a large land mass (Malay Peninsula, Sumatra, Java, Bali and Borneo).

On the other side, was "Sahul" which comprised Australia, Tasmania and New Guinea. In between was “Wallacea”, formed by the islands of Flores, Timor, Celebes (Sulawesi), Lombok and other lesser ones.

Homo erectus the sailor

So, to get to Flores Island, our distant ancestor had to master the art and craft of watercraft building, as well as that of navigating. Quite a feat, which until recently science did not consider possible (the oldest human navigators were believed to be the Homo sapiens who entered Australia some 50 to 60,000 years ago.

For this reason Verhoeven’s claim was ignored (and also because he was an amateur who published in German in an Anglo speaking scientific world).

In 1994 another Dutch group, headed by Paul Sondaar, [2] dated the soil using a paleomagnetic method at a site called Mata Menge to an age of 750,000 years.
Later dating by fission-track method confirm the date, and place it 800,000 years ago. This means that these primitive humans were not so primitive and had quite developed cognitive abilities, such as a language to ensure cooperation between sailors and ship-builders.[3]

However there are skeptics: as only tools, not erectus bones have been found some some believe that these may be natural and not man-made artifacts.

There is more evidence to support the idea of erectus in Flores: the islands’ odd mix of giant komodo dragons and tortoises plus pygmy stegodon elephants all became extinct quite suddenly some 900,000 years ago. Did humans cause these extinctions?

The distance from Sumbawa Island to Flores is some 19 km (12 mi), and before that the straits between Sumbawa and Bali (25 km or 16 mi ) had to be crossed also. This could not be done by swimming. Furthermore, a stable population would have been required to produce the tools found at Flores and span such a long period of time.

The American link

Of course, the tall volcanoes of Indonesia’s islands would have let men see where they were going even if they did not see the coast of the islands. They knew where they were going.

If erectus had gone on towards Australia as some believe, he would have ventured into the unknown, and had to cross a longer stretch of open sea. To reach America along the northern coastal waters of Asia along Beringia and then down the Western coast of America would have been quite a feat, and would have needed sturdy, well built craft.

Perhaps H. erectus reached Melanesia, and when modern humans reached this region, mixed with them, sharing part of their genome with us: The DNA from H. erectus remains from Denisova, Siberia, shows current Melanesians share about 5 percent of their DNA with these Denisovans, a sign of ancient interbreeding.

At Flores, nearly one million years ago, they perhaps floated across on bundles of bamboo. They may have even undertaken the first voyage accidentally, pushed by the wind while fishing close to the shore. Perhaps they later learned to assemble their rafts to deliberately cross the sea in a safer way.

Until modern humans appeared in Africa some 170,000 years ago, and then moved out of Africa and displaced / replaced erectus there was a long span of time during which the more archaic humans could have moved on, from Asia and into America. Where they settled until modern humans moved in too less than 50,000 years ago.

Update. Jan. 21, 2011: Crude stone tools found in Crete, Greece dated to some 130 - 700,000 years ago indicate that H. erectus crossed at least 65 km (40 mi) of open sea to reach Crete from the mainland. (see my post on this find Homo erectus navigator reaches Crete).

Sources.

[1] Verhoeven, Theodor, (1968). Vorgeschichtliche Forschungen auf Flores, Timor und Sumba. Athropica: Gedenkschrift zum 100. Geburtstag von P. W. Schmidt, Studia Instituti Anthropos No. 21, St. Augustin, pp. 393-403.
[2] Sondaar, P. Y., van den Bergh, G. D., Mub-roto, B., Aziz, F., de Vos, J., and Batu, U. L., (1994). Middle Pleistocene faunal turnover and colonization of Flo-res (Indonesia) by Homo erectus. Comptes Rendus de l'Academie des Sciences Paris 319: 1255-1262.
[3] Morwood, M,J., O'Sullivan, P.B., Aziz, F., & Raza, A. (1998). Fission-track ages of stone tools and fossils on the east Indonesian island of Flores. Nature, 392(6672):173-176.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia

2011 International Year of Forests Copyright 2009-2011 by Austin Whittall ©