The recent findings in Sulawesi, Indonesia, have revised the timeline for early human sea crossings, adding complexity to the puzzle of their creators.
Archaeologists have unearthed stone tools at a location in South Sulawesi, called Cario, dating back at least 104 million years. Given that Sulawesi is encircled by swift and deep waters, anyone who created these tools would have had to navigate the open ocean.
“This represents the earliest known evidence of early human presence in Sulawesi,” says Professor Adam Brumm from the Australian Center for Human Evolution Research at Griffith University, which co-directed the research. BBC Science Focus.
“It now seems evident that early hominins managed to cross the Wallace Line, leading to isolated populations on distant islands.”
The Wallace Line serves as a critical biogeographical boundary between mainland Asia and Wallacea Island. “For land mammals that don’t fly, such as those in Sulawesi, crossing from the edge of mainland Asia to the nearest Wallacea island would have been nearly impossible due to the vast distances and swift currents,” Brumm explained.
Earlier discoveries indicated that hominins arrived at nearby Flores Island approximately 102 million years ago, evolving into species like Homo floresiensis (nicknamed “The Hobbit” due to its stature) and Homo luzonensis.
However, as of now, no fossils have been discovered in Sulawesi, leaving the identity of the tool’s maker an enigma.
“We suspect it was an early Asian human species, possibly Homo erectus,” Brumm remarked. “I doubt they used boats for this journey. The colonization of the island likely occurred accidentally as they might have clung to logs or natural vegetation ‘rafts’ that were formed during tsunamis.”
If Homo erectus made it to Sulawesi more than a million years ago, they may have been carving out their own evolutionary niche.
“In Flores and Luzon, fossil discoveries indicate that hominins on these islands underwent evolutionary changes, leading to unique new species that are small and distinct,” noted Brumm. “Though we have yet to find human fossils in Sulawesi, the possibility of similar events occurring on the island cannot be ruled out.”
What’s next for Brumm and the team? “We’re continuing our excavations,” he stated. “Human fossils are incredibly rare, but millions of hominins have existed and perished over the last million years, so there might be preserved remains of these toolmakers out there.”
“We hope to discover a fossil—or two—with persistence (and a bit of luck), as finding one would be an extraordinary breakthrough, perhaps even a game changer.”
Research details will be published in Nature.
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About our experts
Adam Brumm is a professor of archaeology at Griffith University. His work has accumulated over 21 years of funding for research in Indonesia. His published studies include many in Nature, spanning topics from the discovery of new human fossils in Wallacea (the island region between Asia and Australia) to recent insights into human evolution.
Source: www.sciencefocus.com
