A 4,000‑yr‑old Rock Painting in Indonesia Offers Clues to One of Humanity’s Greatest Migrations

Around 4,200 years ago, a group of people embarked on a monumental migration from Taiwan to a multitude of islands stretching from Madagascar in the western Indian Ocean to Rapa Nui (Easter Island) in the eastern Pacific Ocean. This mass migration created the largest-scale language dispersal in prehistory, known as the Austronesian language family.

This family encompasses languages such as Malay, Javanese, Sundanese, Tagalog, Cebuano, and Malagasy, among others. The Austronesian people are believed to have begun their voyage around 4,200 years ago, as evidenced by the appearance of characteristic Austronesian red pottery and rectangular stone adzes on islands south of Taiwan.

The Austronesian people's extraordinary seafaring abilities were facilitated by their use of outrigger canoes. However, the driving forces behind their extensive migration remain unclear. Earlier theories suggested that advancements in rice farming and storage, due to pottery, may have spurred population growth, leading the Austronesian people to seek new farmland on neighboring islands.

An alternative hypothesis posits that a powerful and charismatic shared cultural identity among the Austronesian people was the catalyst for their daring voyages to remote uninhabited islands.

Archaeological evidence for this shared cultural identity is challenging to find, but rock art provides a useful clue. Australian anthropologist Chris Ballard observed in 1992 that a specific style of red rock paintings, known as the Austronesian Painting Tradition (APT), is found primarily in areas where Austronesian languages are spoken today.

These paintings, characterized by small human figures wielding weapons or on boats, as well as geometric sun ray motifs with concentric circles and radiating spokes, are absent in neighboring regions where Papuan languages are spoken. While the exact age of the APT tradition has been difficult to ascertain due to the difficulty of dating art on walls, a 4,000-year-old painting of a sunburst in southeastern Indonesia offers a potential breakthrough.

During a 2023 archaeological investigation on the island of Wetar in southeastern Indonesia, led by researchers from the Indonesian National Research and Innovation Agency, a large rock overhang called Huknaur was identified. Excavations at Huknaur in 2024 revealed a stone plaque painted with the APT sun ray motif in a layer dated to 4,000 years ago using radiocarbon dating.

This symbol aligns with designs found on cliff walls across the APT region, including in the Philippines, Timor-Leste, and southeastern Indonesia. Historical documents also reveal that these sun ray symbols were applied to boat prows in the region, serving both protective and clan identity purposes.