A new archaeological study led by the University of Oxford in collaboration with Universitas Gadjah Mada has identified the oldest plant artefact made by our species outside of Africa in a cave in West Papua.
The findings – published in the journal Antiquity – suggests that the earliest Pacific seafarers arrived in West Papua over 55,000–50,000 years ago, introducing to the region complex plant processing and maritime skills.
Lead author, Dr Dylan Gaffney, of the University of Oxford’s School of Archaeology,said, “Charting the earliest dispersals of people into West Papua is vital because it lies at the gateway to the Pacific, and helps us understand where the ancestors of the wider region – including Australia, Aotearoa/New Zealand and Hawai‘i – came from and how they adapted to living in this new and unfamiliar sea of islands.”
Despite the Pacific’s critical importance for global population movements, scientists have not yet been able to pin down exactly when and where early humans travelled on their journey into the region. At this time, the Earth was in an Ice Age, meaning that sea levels were lower: the large continental shelves around Asia (called Sunda) and Australia (called Sahul) were exposed as dry land, but many of the islands of Southeast Asia remained islands.
Our species – Homo sapiens – may have moved along a northern route from what is now Borneo into Sulawesi, Maluku, and then West Papua, or a southern route from present-day Java and Bali to Flores, Timor, and then Australia.
Previous research has hinted that seafarers arrived to Sahul perhaps as early as 65,000 years ago, while other archaeologists insist that these maritime crossings did not take place until after 50,000 years ago.
This new study, carried out on Waigeo Island in West Papua, off the coast of Ice Age Sahul, provides the first detailed evidence for the earliest stage of human arrival along the northern route into the Pacific. The findings demonstrate that Waigeo was an important stepping stone visited by the first seafarers. At this time Waigeo was part of a larger “palaeo-island” which the research team have named Waitanta. This palaeo-island split into a series of smaller islands including Waigeo at the end of the Ice Age, when sea levels rose.
Computer modelling and chemical isotope studies carried out by the researchers show that Waitanta contained patches of rainforest and a large valley system, and it was separated from Sahul by a deep-sea strait only a few kilometres wide.
The team’s excavations at a large cave site called Mololo, in the interior of ancient Waitanta, uncovered rare evidence for human settlement and behaviour, including animal bones and a small rectangular tree resin artefact. The latter was directly dated at the University of Oxford’s radiocarbon accelerator to show it is 55,000–50,000 years old and the oldest plant artefact made by our species outside of Africa.
The researchers believe the artefact was produced in a multistep process by cutting the bark of a resin-producing tree, allowing it to harden, and then snapping it into shape, possibly to use it as a fuel source for fires inside Mololo cave.
Professor Daud Tanudirjo of Universitas Gadjah Mada, the co-director of the study, said, “The use of complex plant processing indicates these humans were sophisticated, highly mobile, and able to devise creative solutions to living on small tropical islands.”
The archaeological findings from Mololo provide the first firm, directly radiocarbon dated evidence that humans moved through the northern route to the Pacific region before 50,000 years ago. This indicates that small rainforested Pacific islands along the equator were key places for human migration and adaptation.
This new evidence demonstrates that Homo sapiens living along the northern route were skilled seafarers that could deliberately move between islands and that they developed complex, multi-step tool making that involved local rainforest plants to support their livelihoods.
The research team are continuing their archaeological research in West Papua, in the form of a large project funded by National Geographic that seeks to understand how early people adapted to the Pacific region and changed their behaviours in response to past climate change.