A remarkable archaeological discovery from the seafloor of the Madura Strait has recently opened a new window into the past, transforming our understanding of Homo erectus in Southeast Asia.
For the first time, fossilized remains of early humans estimated to be around 140,000 years old have been found in an area now submerged by the sea. This provides fresh insight into the spread and way of life of Homo erectus in what was once known as Sundaland.
Ancient Fossils from a Sunken World
The discovery emerged from a seabed dredging operation in the Madura Strait, the body of water between the islands of Java and Madura.
Amid the dredging activity, researchers uncovered more than 6,000 fossil remains, including two Homo erectus skull fragments and fossils from 36 different vertebrate species. This marks the first time vertebrate fossils have ever been recovered from the seafloor in Indonesia.
What makes this discovery especially significant is its location, on the seabed that was once part of the vast lowlands of the Sunda Shelf. During the last glacial period, global sea levels dropped by more than 100 meters as massive volumes of water were locked in polar ice sheets. At that time, Sundaland was exposed, forming a terrestrial habitat for a range of life forms, including Homo erectus.
Changing Perspectives on Javanese Homo erectus
Previously, archaeologists believed that Homo erectus in Java lived in isolation for hundreds of thousands of years. Well-known sites such as Trinil, Sangiran, and Ngandong have long served as primary evidence of their existence. However, the recent discovery in the Madura Strait challenges that long-standing view.
These fossils reveal that Homo erectus also inhabited lowland areas that are now submerged beneath the sea. They were not confined to mountainous or highland regions but instead spread across the vast river systems that once flowed through Sundaland. These rivers provided freshwater, fish, shellfish, fruits, and seeds, key components of their diet.
Harold Berghuis, an archaeologist from Leiden University involved in the study, explained that the riverbanks offered abundant natural resources year-round. The fossils also bear cut marks on freshwater turtle bones and show fractured cow bones, indicating hunting practices and marrow consumption, behaviors not previously observed in Javanese Homo erectus.
Signs of Contact with Other Hominin Populations
Interestingly, the hunting patterns of Homo erectus in Sundaland suggest they targeted large, healthy animals, not just scavenged carcasses. This behavior has previously only been associated with modern humans on the Asian mainland. It raises the possibility that Homo erectus may have come into contact with, or even interbred with, other hominin groups beyond Java.
Exploring the Ancient Ecosystem of Sundaland
The research also reveals a richly diverse prehistoric ecosystem. During its time, Sundaland resembled the modern African savanna, vast grasslands with forest corridors along rivers, inhabited by large animals such as elephants, rhinoceroses, wild cattle, crocodiles, Asian hippos, and even river sharks.
Most of these species are now extinct or extremely rare. For example, Komodo dragons today are found only on the islands of Komodo and Flores, while river sharks are now exceedingly rare in Southeast Asia. Yet, in ancient Sundaland, these animals once thrived and reproduced.
International Collaboration
This study is the result of a collaboration between Indonesian and international researchers from the Leiden University (Netherlands), University of Tokyo (Japan), Twente University (Netherlands), Shandong University (China), Wollongong University (Australia), and Griffith University (Australia).
The findings have been published in the scientific journal Quaternary Environments and Humans, and all discovered fossils are now stored and preserved at the Geological Museum in Bandung.
According to Shinatria Adhityatama of Griffith University, this discovery proves that Indonesia's underwater archaeology is not only about shipwrecks but also holds extraordinary traces of ancient life. He hopes the research will encourage further exploration of submerged landscapes such as Sundaland and Sahul.
Unggul Prasetyo from the Geological Museum also emphasized the significance of the find in reconstructing past environments and life histories. The fossil deposits were found in a submerged river valley, part of the Solo River system—which gradually transformed into a tidal environment as sea levels rose.
