The hair contained psychoactive alkaloids, which are found naturally in some plants and can induce altered states of consciousness. Archaeologists think that ancient humans may have ingested them during ritual ceremonies.
The hair strands came from a cave in Menorca, a Spanish island in the Mediterranean Sea off the eastern coast of mainland Spain. Humans first began inhabiting the cave, known as Es Càrritx, around 3,600 years ago, say the researchers in a statement.
Spelunkers stumbled upon Es Càrritx in 1995. Once archaeologists started excavating the site, they discovered the remains of roughly 210 individuals, as well as sealed, decorative containers full of strands of hair that had been dyed red.
Using high-resolution mass spectroscopy and ultra-high-performance liquid chromatography, researchers carefully tested the hairs. They found atropine and scopolamine, two alkaloid substances that can cause hallucinations, delirium and altered sensory perceptions. They also discovered ephedrine, a stimulant that can cause increased alertness and excitement.
Our Bronze Age ancestors likely consumed those compounds by eating certain plants, including mandrake, henbane, horn apple and joint pine. Scientists concluded that these individuals had been ingesting the drugs over the span of at least a year.
Why these communities were consuming the substances isn’t entirely clear, though the team suspects shamans may have used them while performing religious ceremonies. The containers that held the hair were decorated with concentric circles, which the researchers say could have symbolized the “inner vision” gained by ingesting the plants.
“This was not a profane purpose of ‘searching for a high’ but more generally the search for existential meaning that has been largely lost to time,” says Giorgio Samorini, an independent ethnobotanist who was not involved in the new research, to the New York Times’ Andrew Jacobs.
The researchers write that while mind-altering drugs are “usually invisible in the archaeological record,” their existence “used to be inferred from indirect evidence,” such as residue on pieces of pottery. The hairs, however, provide the first direct proof of drug consumption among Europeans.
Few hairs are still in existence from this period and this region. As study co-author Elisa Guerra Doce, a prehistorian at the University of Valladolid, tells National Geographic’s Tom Metcalfe, “We are very, very lucky.”