Archaeologists working in South Africa believe they have found what could be one of the oldest mixed poisons in the world.
While researching early human techniques, they found multi-component poison on weapons that date back an incredible 7,000 years.
This discovery also gives an insight into how advanced ancient people’s pharmacological knowledge was, even during the Neolithic period several thousand years ago.
The artefact – an antelope femur bone – was first discovered in 1983 at Kruger Cave in South Africa but went unexamined for decades.
A few years ago, it was finally analysed and was found to contain three bone arrowheads in its marrow cavity. Further scans confirmed this contained a sediment-like substance in which two known poisons were found.
Justin Bradfield conducted chemical tests at the University of Johannesburg and confirmed the presence of two glycosides – digitoxin (from foxgloves) and strophanthidin (from Strophanthus plants) – both classified as poisonous and disrupt the heart’s function.
Ricinoleic acid – the main component of castor oil – was also identified in the examined sample.
The scientists are confident the mixture was deliberate and that the chemicals were intentionally extracted from plant-based toxins. This confirms that early humans could combine poisonous ingredients to enhance their hunting efficiency.
The research team wrote: “This is the oldest unequivocal complex hunting poison recipe yet identified, notwithstanding the many chemically unsupported assertions of older examples.”
Crucially, however, the plants used to create the mixed poison were not native to the environment near Kruger Cave.
This suggests that early humans either travelled long distances to acquire the ingredients for the substance or had some form of exchange network.
Such a revelation has not surprised the researchers, as long-form transportation of goods, including shells, has been acknowledged in other studies. However, it would be unprecedented if botanical trade were to be confirmed.
The use of poison for hunting is believed to have started as far back as 60,000 to 70,000 years ago, coinciding with the creation of projectile technology.
In their paper, the researchers said: “The use of poison as a hunting aid when applied to spears and arrows signals an evolutionary advancement in the development of hunting technology.”
While earlier uses of toxic chemicals have been discovered, including ricinoleic acid found on a 24,000-year-old spatula at Border Cave in South Africa, the Kruger Cave discovery is the oldest confirmed use of a complex poison mix.