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Discovery of Ancient Stone Tools on Sulawesi

Archaeologists have made a groundbreaking discovery that has deepened the mystery surrounding early human ancestors on an island in Indonesia. The earliest evidence of hominin presence on the island of Sulawesi, which is located near the island known as "Hobbit," dates back over one million years. This finding suggests that early hominins made a significant journey across deep seas to reach this region much earlier than previously believed.

The research was conducted at the Calio site, an Early Pleistocene location that corresponds to the Ice Age. The site has revealed stone tools that are at least 1.04 million years old. These tools were found by a team led by Budianto Hakim from the National Research and Innovation Agency of Indonesia (BRIN). The team excavated seven stone artifacts from sedimentary layers in a sandstone outcrop situated in a modern corn field in southern Sulawesi.

According to the researchers, the Calio site would have been a hub for hominin activity during the Early Pleistocene period. It is believed that the area was used for tool-making and hunting, particularly near a river channel. The artifacts consist of small, sharp-edged fragments of stone, which were likely struck from larger pebbles collected from nearby riverbeds.

To confirm the age of these tools, the team employed palaeomagnetic dating of the sandstone itself and directly dated a pig fossil found at the site. This method provided a reliable estimate of 1.04 million years for the artifacts.

Professor Adam Brumm, who leads the research team, has previously discovered evidence of hominin occupation in the Wallacea region, which includes the islands of Flores and Sulawesi. His team had identified stone tools at Wolo Sege on Flores, dating back to at least 1.02 million years ago, and at Talepu on Sulawesi around 194,000 years ago. Similarly, on the island of Luzon in the Philippines, evidence of hominins has been found from approximately 700,000 years ago.

Brumm, from the Australian Research Centre for Human Evolution at Griffith University, emphasized the significance of the Calio discovery. He noted that it contributes to our understanding of how extinct humans moved across the Wallace Line, a transitional zone where unique animal species evolved in isolation. However, he also pointed out that no hominin fossils have been found at the Calio site yet. While we now know that there were tool-makers on Sulawesi a million years ago, their identity remains unknown.

The original discovery of Homo floresiensis, or the “hobbit,” and subsequent 700,000-year-old fossils of a similar small-bodied hominin on Flores, also led by Brumm’s team, suggested that Homo erectus might have crossed the marine barrier between mainland Southeast Asia to inhabit the small Wallacean island. Over time, they may have undergone island dwarfism.

Brumm's recent find on Sulawesi, published in the journal Nature, has raised new questions about what might have happened to Homo erectus on an island more than 12 times the size of Flores. He described Sulawesi as a “wild card” due to its vast size and ecological richness. If hominins were isolated on this large and diverse island for a million years, would they have experienced the same evolutionary changes as the Flores hobbits? Or would something entirely different have occurred?

This discovery continues to challenge our understanding of early human migration and evolution, leaving many questions unanswered about the people who once inhabited these ancient landscapes.