The use of poisoned hunting weapons is one of the most important innovations in the history of humans obtaining meat and has intrigued researchers for centuries. Until now, the oldest evidence came from bone arrowheads with traces of toxic glycosides found in Kruger Cave, South Africa, dating back to the mid-Holocene, about 6,700 years ago. However, a study published Wednesday in the journal Science Advances significantly extends that timeline. The research shows that around 60,000 years ago, the first modern humans were already using poisoned arrows to hunt in southern Africa, a finding that demonstrates that these inhabitants possessed more complex technology than previously thought.
Archaeologist Sven Isaksson and his team analyzed the chemical residue of toxic substances preserved on tiny stone arrowheads (microliths) extracted from the Umhlatuzana Rock Shelter site in South Africa’s KwaZulu-Natal province. “The direct evidence prior to this analysis also came from southern Africa, but it was about 7,000 years old. In addition, there was indirect evidence, such as tubes used to apply the poison,” Isaksson explains. For this professor and researcher at Stockholm University, the discovery reveals advanced mental capabilities. “We are talking about modern humans, with advanced cognitive abilities and complex cultural knowledge,” he explains.
The team found 10 quartz microliths. Analysis revealed that five of them contained two toxic plant alkaloids: buphandrin and epibuphanisine. These substances are derived from Boophone disticha, or tumbleweed. Toxicological tests showed that even small amounts of this plant can be lethal to rodents. In humans, symptoms can include nausea, muscle weakness, visual disturbances, respiratory paralysis, altered pulse, and coma.
Delayed-action weapons
The researchers explained that while Boophone disticha has been used by hunter-gatherer communities to poison arrows, in low doses, it can have medicinal effects. According to Isaksson, the discovery also speaks to the botanical knowledge of those groups. “People have used plants for a very long time,” he notes, “as food, to make tools, and also deliberately for their chemical properties, whether as medicine, drugs, or poisons.”
Poisoned arrows weren’t designed to kill instantly. They were more like delayed-action weapons: the wounded animal flees, but the poison acts slowly, weakening it until it collapses. Meanwhile, the hunter must track it for miles. “The poison wounded the animal and entered its bloodstream,” Isaksson emphasizes.
The analyzed microliths exhibited fractures and micro-striations typical of projectile impacts, as well as traces of complex adhesives mixed with mineral pigments. “When these tiny samples appeared, I had to adjust the protocols we use in the lab,” the archaeologist explains. “I had to make sure they were intact, uncontaminated, and that nothing was lost along the way.”
What did they hunt? Researchers can’t say for sure. The bone material from the Umhlatuzana site is highly fragmented and doesn’t allow for precise species identification. However, comparison with other, better-preserved contemporary sites suggests that they primarily hunted small and medium-sized game. “They typically hunted animals like wild boar, small antelope, or springbok,” explains the archaeologist.
Part of the key to the discovery, he emphasizes, lies in the exceptional conditions of the South African site where the arrows were found: “Some chemical properties of the layers at the site are especially good for preservation.” Previous geochemical studies have shown that the soil has undergone very little alteration from the activity of living organisms, which favored the preservation of the remains.
“We hadn’t worked with such a large set of ethnohistorical samples before,” Isaksson adds. “These samples can contain hundreds of components, many of them functional and polar groups that don’t survive for long in an archaeological context. But among them were a few, and among those, the two alkaloids that we were finally able to identify.”
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