Betel Nut Habit Dates to Ice Age Sulawesi Foragers

Archaeologists have identified evidence that hunter-gatherers on Sulawesi were habitually sucking areca, or betel, nuts as early as 25,000 years ago. The conclusion rests on two unusual features found in the remains of two early foragers: deep, rounded grooves worn into their teeth and the presence of arecoline, the principal psychoactive alkaloid in betel nut, in preserved dental tissue. Together, the observations provide biochemical and archaeological evidence for repeated consumption of a psychoactive plant during the Late Pleistocene, potentially the earliest recorded evidence of habitual use of a neuroactive plant drug anywhere in the world.

The peer-reviewed study, published in Science Advances, investigated the origins of betel-nut use, a practice now widespread across much of the Asia-Pacific region, from India to the South Pacific. Contemporary users chew a quid made from a processed areca seed, slaked lime and other ingredients. The lime causes a chemical reaction that releases the nut’s psychoactive compounds into the bloodstream more rapidly, while consumption can produce mild euphoria and heightened alertness. Until the new findings, previous accounts placed the beginning of betel use in the Neolithic or Bronze Age, around 3,500 years ago. The Sulawesi evidence instead points to a substantially earlier practice among some hunter-gatherers, long before agriculture developed there.

Investigators led by Professor Adam Brumm of Griffith University’s Australian Research Centre for Human Evolution, with Associate Professors Carney Matheson and Michelle Langley and Indonesian collaborators from Hasanuddin University and the National Research and Innovation Agency, examined extremely rare skeletal remains from Sulawesi. One individual lived between 25,000 and 16,000 years ago; the other lived between 7,600 and 6,300 years ago. Both displayed a highly unusual pattern of dental wear characterized by deep, rounded grooves. The researchers established through experimental and archaeological evidence that this pattern was caused by the habitual sucking of whole betel nuts, a behaviour that could otherwise be difficult to recognize because areca seeds are rarely preserved at archaeological sites.

The team investigated how intact nuts might release their psychoactive compounds. In laboratory experiments, researchers soaked betel nuts in artificial saliva and tested the resulting broths against a panel of cloned human receptors expressed in frog egg cells. These receptor proteins act as molecular switches involved in regulating neural activity. The experiments showed that sucking an intact nut can release arecoline in amounts sufficient to have a physiological effect and alter brain function. This differs from the established preparation used in modern quids, in which chewing a processed seed with slaked lime converts arecoline into a more rapidly bioavailable free-base form. The cell-based experiment addressed arecoline release and physiological activity; it did not directly test the mechanism responsible for dental damage or reproduce the subjective experience of the prehistoric users.

Chemical analysis supplied an additional line of evidence for ingestion. Matheson detected arecoline in the dental tissues of both foragers, supporting the interpretation that the unusual grooves were associated with habitual betel-nut sucking rather than another activity involving hard objects. The older specimen places the behaviour as early as 25,000 years ago, in the Late Pleistocene, while the later specimen shows that it remained present among Sulawesi foragers thousands of years afterward. Because the study concerns two individuals from one island, it cannot establish how widespread the practice was across Sulawesi or the wider Asia-Pacific region. Its broader significance is that it documents habitual psychoactive-plant use with direct archaeological and biochemical support among people living without agriculture.

The discovery challenges a common account in which the earliest long-term traditions of psychoactive drug use arose after the Neolithic expansion of farming. Under that view, fermented alcoholic drinks, including barley beer produced about 13,000 years ago in Israel, marked an early stage in the history of psychoactive substances. The Sulawesi research shows that at least one major plant-drug tradition has roots in a hunter-gatherer context. It does not rewrite the complete chronology of human drug use, and the authors described the finding as possibly the earliest evidence of habitual neuroactive-plant use worldwide rather than as definitive proof that no earlier example survives.

The findings also connect habitual drug use with oral pain and deteriorating dental health. Arecoline acts as a natural analgesic, leading the research team to suggest that one reason for sucking betel nuts may have been to relieve toothache or other oral discomfort. The seeds were hard and abrasive, and repeated sucking wore down the teeth severely. In some cases, the inner pulp chamber became completely exposed. Brumm said this would have been extremely painful, could have made eating difficult and greatly increased the rate of chronic infection. The researchers therefore proposed a self-reinforcing cycle in which the nuts reduced discomfort, continued use caused further damage and the resulting pain encouraged further use. Ancient foragers on Sulawesi generally had poor teeth, but the study does not establish betel-nut sucking as the only cause of their dental disease.

The older and younger skeletons also demonstrate that the behaviour was not a single incident confined to one exceptional period. The first provides evidence for a Late Pleistocene origin, while the second, dated to between 7,600 and 6,300 years ago, records the practice much later. That separation in time supports the authors’ interpretation that nut sucking was an enduring feature of at least some forager traditions on the island. It was also a different mode of consumption from contemporary betel chewing: the prehistoric users appear to have sucked whole seeds rather than preparing a processed seed and lime mixture. The study therefore suggests that the ancient behaviour underlying modern betel-nut use is deeply rooted in the practices of hunter-gatherers.

Several qualifications constrain the conclusions. The archaeological sample consists of only two skeletons, and the reconstruction depends on interpreting their dental grooves alongside the detection of arecoline and laboratory tests involving cloned human receptors expressed in frog egg cells. The dates are also ranges, not precise moments when the habit began; the evidence establishes that betel-nut sucking was occurring by up to 25,000 years ago in Sulawesi, not that its origin can be fixed to a single date. The claim that this may be the earliest recorded example worldwide is necessarily limited by the incomplete and uneven archaeological record. Despite those restrictions, the combined findings provide unusually direct evidence that habitual psychoactive-plant use, visible anatomical consequences and possible pain relief were already present among Sulawesi hunter-gatherers tens of thousands of years before the later development of agriculture.

Subject of Research: Archaeological and biochemical evidence for habitual betel-nut use among prehistoric hunter-gatherers in Sulawesi

Article Title: Ice Age origins of one of humanity’s oldest drug habits

Article References: Ice Age origins of one of humanity’s oldest drug habits. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: betel nut, Sulawesi, hunter-gatherers, arecoline, archaeology, dental wear, psychoactive plants, Late Pleistocene, bioarchaeology, forager traditions, origins, humanity