Key points
- Oldest evidence of hominins in Wallacea region discovered
- Tools may link to Flores’ ‘hobbit’ human ancestors
- Hominins possibly arrived via accidental ocean crossings
ISLAMABAD: Archaeologists have uncovered primitive stone tools on the Indonesian island of Sulawesi that could reshape our understanding of early human migration across Southeast Asia.
The flaked stone artefacts, dated between 1.04 and 1.48 million years ago, are now the oldest known evidence of human presence on the island — and potentially the entire Wallacea region, reports CNN.
The discovery of ancient stone tools on Sulawesi suggests that this Indonesian island was populated by hominins at around the same time as the nearby island of Flores, if not earlier, according to a paper in @Nature. https://t.co/jU5kYZffxR pic.twitter.com/1J0b1YjYDI
— Nature Portfolio (@NaturePortfolio) August 6, 2025
The discovery, published this week in Nature, adds weight to theories that ancient hominins may have settled Sulawesi long before the emergence of the so-called “hobbits” — Homo floresiensis — on the nearby island of Flores.
These small-bodied humans lived on Flores from about 700,000 to 50,000 years ago and are thought to have descended from an isolated population of Homo erectus.
Earlier migration
“We’ve long suspected the ancestors of Homo floresiensis originated in Sulawesi,” said Dr Adam Brumm, co-lead author of the study and professor at Griffith University’s Australian Research Centre for Human Evolution. “This new finding supports the idea of an earlier migration through the region.”
The tools, discovered at the Calio site in 2019 by Indonesian archaeologist Budianto Hakim, were embedded in ancient sandstone near a modern riverbed.
Island hominids from more than 1 million years ago left tool clues.https://t.co/UcnYtdmyMQ
— Science News (@ScienceNews) August 7, 2025
Excavations unearthed seven sharp-edged tools made from local river pebbles, likely used for cutting or scraping. Animal fossils were also found nearby, including the jawbone of the extinct Celebochoerus, a pig with large upper tusks.
Radiometric dating places the tools at between 1.04 and 1.48 million years old — far older than previous evidence of hominin activity on Sulawesi, which dated only to around 194,000 years ago.
Human fossils
In comparison, similar tools discovered on Flores were dated to about 1.02 million years ago, suggesting early humans may have reached Sulawesi even earlier.
Despite the significance of the tools, no human fossils have yet been found at Calio. “It’s a vital clue, but the toolmakers’ identity remains unknown,” Brumm said. “We know someone was here a million years ago, but we don’t yet know who.”
Researchers believe the tools were likely made by Homo erectus or a similar early hominin — perhaps even an ancestral population that gave rise to Homo floresiensis.
However, confirming this will require finding fossils, which remains difficult in Sulawesi’s tropical climate where DNA degrades quickly.
Previously unknown human group
Brumm and his team previously retrieved ancient DNA from a 7,000-year-old hunter-gatherer on Sulawesi, revealing a previously unknown human group. But such discoveries remain extremely rare due to poor preservation conditions and limited exploration.
Wallacea — a region of hundreds of islands between mainland Asia and Australia — presents a challenge for archaeologists. Many islands remain unstudied, and how early humans crossed the sea to reach them remains a mystery.
“Crossing from mainland Asia to Sulawesi would have required some form of ocean travel,” said Brumm. But whether early hominins had the capacity for planned sea voyages is unclear. Researchers suggest they may have arrived accidentally — drifting on vegetation mats, similar to how some animals are believed to have crossed seas.
Ancient human ocean crossings
The new finding adds to growing evidence of ancient human ocean crossings. Tools dating to over 700,000 years ago were previously found on Luzon in the Philippines, north of Wallacea, further suggesting that multiple hominin groups reached isolated islands long before modern humans.
New tool discoveries show that early humans crossed a major deep-sea barrier to reach the Indonesian island of Sulawesi much earlier than previously thought. https://t.co/iORJPXEcIa pic.twitter.com/T5d4Z0XieO
— Interesting Engineering (@IntEngineering) August 7, 2025
Some experts, like Professor John Shea of Stony Brook University, say the finding is not a game-changer but an important piece in the puzzle of early human dispersal. “Just because they reached these islands doesn’t mean they survived long-term,” he said. “Only Homo sapiens managed to spread globally and endure.”
Brumm and his team plan to continue excavations in Sulawesi, hopeful that fossils will eventually reveal the identity of these early toolmakers.
“Sulawesi is like a mini-continent with unique ecosystems,” Brumm said. “If Homo erectus became isolated here, it may have followed a very different evolutionary path than those on Flores. There’s a fascinating story still waiting to be uncovered.”