Ancient Sulawesi Teeth Show 25,000-Year-Old Betel Nut Habit

Archaeologists have pushed back the origins of habitual human drug use by tens of thousands of years. A team from Griffith University in Australia found evidence that hunter-gatherers on the Indonesian island of Sulawesi were using psychoactive betel nut as far back as 25,000 years ago.

The research, led by Professor Adam Brumm of Griffith's Australian Research Centre for Human Evolution, was published in Science Advances. It challenges the theory that widespread psychoactive substance use only emerged with farming societies during the Neolithic period.

Rethinking the Timeline of Drug Use

Previous estimates placed the beginnings of betel nut use around 3,500 years ago, in the Neolithic or Bronze Age. The new discovery from the Late Pleistocene period is far older. Professor Brumm stated that this theory of Neolithic origins fails to account for the possibility of very ancient drug-taking at the roots of common psychoactive substances.

Betel nut, from the Areca catechu palm, is the world's fourth most widely used psychoactive substance after alcohol, caffeine, and nicotine. It is used by about one in ten people globally today, primarily across the Asia-Pacific region. The substance can produce mild euphoria and increased alertness.

Evidence from Teeth and Chemistry

The researchers examined the skeletal remains of two early human foragers from Sulawesi. One individual lived between 25,000 and 16,000 years ago, while the other dates to between 7,600 and 6,300 years ago. Both exhibited an unusual form of dental wear: deep, rounded tooth grooves.

The team identified this pattern as a new bioarchaeological marker linked to repeatedly sucking whole betel nuts. Biochemical tests led by Associate Professor Carney Matheson detected arecoline, the nut's main neuroactive alkaloid, inside the dental tissues of the ancient foragers. This provided direct chemical evidence of consumption.

Experiments conducted by the team showed that simply sucking on intact betel nuts releases enough arecoline to have a physiological effect, altering brain function. This finding was significant because earlier research suggested the compound became available primarily when the nut was chewed as part of a 'quid' mixed with slaked lime.

A Painful Cycle of Use and Damage

The researchers propose a potential reason for the ancient habit. Arecoline acts as a natural analgesic, or painkiller. Given that the ancient foragers of Sulawesi generally suffered from poor dental health, the team suspects people may have initially sucked betel nuts to ease toothaches.

However, the remedy likely worsened the problem over time. Professor Brumm explained that sucking the hard, abrasive seeds wore down teeth severely. In some cases, the inner pulp chamber became completely exposed. This would have caused extreme pain, difficulty eating, and increased rates of chronic infection.

"So while this habit may have been a remedy for toothache, years of prolonged nut-sucking eventually caused much worse dental health problems, creating a cycle of continued habitual use," Brumm said. The habitual practice contributed to severe periodontal disease.

Implications for Human History

The discovery places the habitual use of a neuroactive substance deep into the Ice Age, long before agriculture. "Emerging by up to 25,000 years ago in Sulawesi, thus long preceding the onset of agriculture, betel nut-sucking may be the earliest evidence for drug use anywhere in the world," Professor Brumm concluded.

The study implies that some modern drug-taking behaviors are deeply rooted in forager traditions. It suggests that repeated psychoactive substance use, along with its accompanying health consequences, was already a part of life for some hunter-gatherer communities tens of thousands of years ago. The research was conducted in collaboration with Indonesian archaeologists from the University of Hasanuddin and the National Research and Innovation Agency.