The early human migration through mainland Southeast Asia (SUNDA) marks the oldest evidence of humans crossing marine barriers to access secluded land. Previously, the earliest indication of Wallacea, an area of oceanic islands east of Sunda, comprised flakestone tools found at Wallosea, Flores Island, dating back at least 152 million years. Excavations in Sulawesi, the largest island, have uncovered stone artifacts at Talep’s open site dating to at least 194,000 years ago. Presently, researchers from Griffith University have identified stone tools at locations close to the fossil-rich cario strata that date back at least 104 million years, possibly extending to 1.48 million years. This information hints that Sulawesi was occupied by humans around the same period as Flores.
Professor Adam Blum of Griffith University and his team discovered seven stone artifacts within the sedimentary layers at the Cariosite.
During the early Pleistocene, this area would have been near river channels, facilitating activities such as tool-making and hunting.
The artifacts from Cario are small sharp stones (flakes) created by larger pebbles, likely sourced from local riverbeds by early human inhabitants.
“This findings enhance our understanding of extinct human migrations across the Wallace Line, a transitional area where unique animal species have evolved independently,” said Professor Blum.
Reconstruction of Homo floresiensis. Image credit: Elizabeth Daines.
Utilizing paleomagnetic dating of the sandstone and direct dating of excavated pig fossils, researchers confirmed that the Cario artifacts are at least 1.04 million years old.
Previously, evidence of human habitation in Warasea had been found dating back at least 102 million years in Talep, Sulawesi, based on stone tools located in Warosea, Wolosage, Flores.
Luzon, located in the Philippines and north of Wallacea, has yielded human evidence dating back approximately 700,000 years.
“This is a critical piece of the puzzle, yet the Cario site has yet to reveal any human fossils,” commented Professor Blum.
“We now recognize that a toolmaker existed in Sulawesi a million years ago, but their identity remains unknown.”
Stone artifacts from the site of Cario in Sulawesi, Indonesia. Image credit: Hakim et al., doi: 10.1038/s41586-025-09348-6.
The initial discovery of Homo floresiensis and subsequent fossils from Flores, similar in size and dating back 700,000 years, implied that it may have been linked to Homo erectus, which managed to bypass substantial marine barriers between the mainland of Southeast Asia to inhabit this smaller island and underwent island dwarfism for eons.
“The revelation of Sulawesi prompts us to consider the fate of Homo erectus on an island more than 12 times larger than Flores,” Professor Blum noted.
“Sulawesi is an unpredictable variable. It’s almost like a mini continent.”
“If hominins were isolated on this expansive, ecologically diverse island for over a million years, would they have evolved in ways similar to the Hobbits of Flores?”
“Or could there have been an entirely different evolutionary path?”
The study was published yesterday in the journal Nature.
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B. Hakim et al. Human presence in Sulawesi during the early Pleistocene. Nature Published online on August 7th, 2025. doi:10.1038/s41586-025-09348-6
Source: www.sci.news
