Throughout history, hunters have coated their dart tips and arrowheads with poison to make them even more deadly. Our prehistoric ancestors, it seems, devised this strategy surprisingly early. A fresh look at ancient weapons shows that people hunted with poison arrows some 60,000 years ago. That’s more than 50,000 years earlier than scientists had thought.
Researchers shared these findings January 7 in Science Advances.
A team analyzed five quartz arrowheads that had been unearthed in South Africa. Their surfaces contained traces of a poison made from a flowering plant called gifbol (Boophone disticha). This plant is also known as the “poisonous onion.”
The newly analyzed arrowheads were found in 1990 at a rock shelter in what’s now South Africa’s KwaZulu-Natal province. They offer “the earliest direct evidence of the use of poison,” says Sven Isaksson. An archaeologist at Stockholm University in Sweden, he was the new study’s lead author. “It’s quite a leap [back]” in time, he says.
Until now, the earliest known poisoned arrowheads were fewer than 7,000 years old.
Same poison, 50,000 years apart
Isaksson’s team first confirmed the ages of the sediments where the arrowheads had been found. Sediments are soil particles such as clay or sand. Knowing their age can help figure out the age of objects buried in them.
Chemical and magnetic properties of the sediments confirmed the weapons were some 60,000 years old.
Then, Isaksson’s group identified chemicals on the surface of the ancient arrowheads. They did this using gas chromatography-mass spectrometry (GCMS). This technique helped them scout for telltale signs of a poison. And sure enough, they found it.
The team also inspected arrowheads made more recently, in the late 1700s. Swedish naturalist Carl Peter Thunberg had traveled to southern Africa. There, he had collected arrowheads used by local hunters. They had been coated with a poison made from a local flowering plant.
Isaksson’s team used GCMS to examine those newer arrows. They, too, contained gifbol. So the same poison showed up on weapons made more than 50,000 years apart.
Scientists don’t yet know if this poison was used throughout that entire 50,000 year span. It could have been discovered and forgotten by different groups of people, Isaksson says.
Prehistoric hunters would not have known exactly how the poison worked. But they didn’t need to. They only needed to be able to identify, extract and apply it. They also would have known this poison doesn’t kill right away. So, the researchers note, “the hunters must also have relied on advanced planning, abstraction and causal reasoning.”
