How to Kill Your Eland: A 7000 Year Old Guide
- Sep 17
- 8 min read
Chemical analysis of preserved residues reveals oldest multicomponent poison used on arrows
How can you make a weapon deadly? Well, there are a number of ways, one of which is poison. Poison has been used on hunting weapons such as spears and arrowheads for thousands of years. However, the oldest known hunting poisons have all been typically derived from a single toxin (single-component poison formulas). Multi-component formulas, or at least the oldest verified one, are believed to have occurred in Egypt around 2,500 to 2,000 BC.
In a study by Dr. Justin Bradfield and his colleagues, Ian Dubery and Paul Steenkamp, a 7,000-year-old multicomponent arrow poison was identified and analyzed. The world’s oldest verified multicomponent arrow poison seems to have come from Kruger Cave, South Africa.
Exactly what was it made from, and what can it tell us about the skills and knowledge of the hunter-gatherers who made it?
A History of Poisons
From ethno-historical records, we know hunters across the world often relied on toxic poisons derived from plants and animals. In southern Africa, this was no different, and many plants and animals were used to create poison-tipped arrows. These poisons were often made by combining various components in complex recipes.
The application of poison to weapons is thought to have started between 70 and 60,000 years ago, around the same time that projectile technology was developed in Africa. This idea is based on the fact that these arrowheads were too small and generally would have been incapable of inflicting death based on impact alone. Thus, an additional component would have been needed to actually take down the desired game, poison.
In effect, the arrows would simply have been the applicators of this toxin.
However, evidence for such poisons is lacking, and the earliest evidence we have from a molecular standpoint of poison comes from a wooden spatula at Border Cave, South Africa.
The wooden spatula, which resembles ethnographic poison applicators, has been dated to approximately 24,000 calendar years before present (cal BP). Chemical analysis of the wooden spatulas detected compounds of the castor oil plant. While the castor oil plant can be used to produce ricin, a highly toxic substance, some of the components of the castor oil plant are non-toxic and can be used for medicinal purposes, i.e., castor oil.
Other unverified claims of poison come from Zanzibar’s Kuumbi cave. Here, putative arrow poison was found on arrowheads from 13,000 cal BP deposits. However, no chemical or other scientific tests were undertaken to verify this interpretation. Similarly, in 13,000 cal BP deposits from Mindoro in the Philippines, the presence of Diodontidae (blowfish) dermal spines has been argued to represent early processing of poisons.
More convincing evidence was found in South Africa on a 1,000-year-old arrow, also from Kruger Cave. Here, cardiac glycosides, aka heart-affecting plant toxins, were positively identified. However, the specific poison could not be determined due to the degradation of the material.
It seems that if early poisons did exist, they were most likely single-component poisons, with the earliest confirmed evidence we have of multi-component poisons coming from Egypt around 2,500 to 2,000 BC.
The mixing of any type of multi-component recipe is impressive, whether it involves poisons, medicines, or adhesives, and thus finding out when and where such complex recipes were first used is important, as they provide insight into the cognitive capabilities and traditional pharmacological knowledge of their makers.
We know that Neanderthals were capable of creating complex recipes for the manufacturing of adhesives 200,000 years ago via the distillation of birch bark. Meanwhile, evidence from southern Africa suggests conifer resin, ochre, and fat were used to create adhesives around 60,000 years ago. These recipes were not just complex, but sometimes required individuals to travel dozens of kilometers to obtain the key ingredients for their manufacture.
It is likely that knowledge of complex medicines and toxins, similar to adhesives, also has a deep antiquity; however, current archaeological evidence dates the oldest confirmed medicine, which used more than one ingredient, to only 500 years ago.
It is unlikely this knowledge was obtained only in the recent past. Bushmen hunters showed an incredibly sophisticated understanding of different plant toxins. For example, coniine was only used to hunt mammals, as it corrupts the meat of fowl.
Similarly, toxins like ricin require different doses to be lethal for different animal taxa. Such complex knowledge likely developed through a long process of trial and error, rooted in antiquity. But to prove that, one needs the archaeological evidence to substantiate it.
Dr. Bradfield and his colleagues analyzed and provided just that bit of definitive proof. Identifying poison arrows from deposits at Kruger Cave, South Africa, dating back to 6,690 ± 50 BP.
Kruger Cave
Kruger Cave is a later Stone Age site situated in the western Magaliesberg region of South Africa. It was originally excavated in 1956 but underwent large-scale excavations under the direction of Revil Mason and his team in the early 1980s. The rationale for these excavations was the rescue and preservation of archaeological data in response to persistent vandalism.
In an effort to preserve the site after excavation was completed in 1983, a fence was erected; however, this measure proved ineffective, and it was partially torn down and removed in 1986. Contrary to standard archaeological procedure, the excavation was never backfilled, meaning the hole the archaeologists dug was left open and exposed to erosion and human activity. Consequently, a further 22.8 m3 of archaeological deposit has been lost to erosion.
Additional risk to the site and its archaeological deposit is posed not only by visitors from the nearby Olifantsnek Dam, but also by a lay Christian pastor who makes the cave his occasional home. Living at the site intermittently since 2013 and on an even more semi-permanent basis since 2018.
The cave is currently subject to rehabilitation work to preserve its rich archaeological deposit. From previous excavations, it is known that Kruger Cave has been occupied for approximately 10,000 years, from around 10,751–7,956 BC to around AD 641-1217. The cave is one of only seven recorded rock art sites in the Magaliesberg and depicts 57 poorly preserved rock art figures, mainly human men with weapons, but also some birds and other animals.
The earliest phase of occupation was characterized by large macro-lithic (stone tool) technology, known as the Oakhurst. This was followed by a second occupation of the site between 6,222–3,901 BC, characterized by somewhat smaller lithics and exceptional organic preservation. It was in this second phase of occupation that the arrow poison was recovered. More specifically, a bovid femur containing three bone arrowheads was recovered from here. The femur, presumably used as a quiver, contained an unknown substance into which the arrowheads had been embedded.
What was this mystery substance? Well, you can probably guess it was poison. But what was it made of, and why is it so special?
Poison Arrows
The arrows themselves were not dated, nor was the femur; however, charcoal associated with the femur provided a radiocarbon date of 6,690 ± 50 BP, which provides a calibrated date of 5,659–5,480 BC. At the time of excavation, the femur had been placed vertically in the ground. This suggests it may have been placed to prevent whatever was inside from spilling out. Not only was the substance not spilled out, but because it had been placed inside the femur, it protected the substance from the worst effects of oxidation and biodegradation, unlike the 1,000-year-old sample from the same cave, which had been found directly in the sediment and thus exposed.
The chemical analysis revealed that the femur contained a complex plant-based poison made up of a mixture of two different types of cardiac glycosides and a fatty acid, possibly indicating the presence of ricin.
The two toxins were digitoxin and strophanthidin. Digitoxin is a cardiotoxin that disrupts the membrane-bound sodium pump, causing dangerous irregular heartbeats, rapid heart rate, and potentially death. Symptoms of digitoxin include nausea, vomiting, and confusion.
It can be derived from Digitalis plants, but primarily from foxglove (Digitalis purpurea). From historical records, we know that Digitalis plants were, in fact, used as arrow poisons. However, despite three different Digitalis varieties occurring in South Africa, they are not native to the country, although two of them are now categorized as naturalized exotics. This essentially means that they have successfully established themselves and propagated independently within the surrounding ecosystem.
The second toxin, Strophanthidin, is also a cardiotoxin affecting the heart; it has relatively similar effects, disrupting the heart’s membrane-bound sodium pump, leading to calcium buildup in the heart muscles. This, in turn, leads to irregular heartbeats and heart failure. The toxin is derived from the Strophanthus plant, which is a commonly used plant poison across Africa.
In fact, the San Ju/wasi informants describe how they would crush the seed of this plant to create hunting poisons, while the same method was used by the Zulu in KwaZulu-Natal. However, the Strophanthus plant does not naturally occur near Kruger Cave, but rather grows in places much further afield, including south-eastern Kenya, eastern Tanzania, eastern Namibia, Botswana, Mozambique, Zimbabwe, and south-eastern South Africa.
This suggests that the plant was acquired from a great distance, either via trade or travel.
The final component found in the arrow poison was Ricinoleic acid, which was also found in the arrow poison, and comes from several plants in South Africa, most notably the castor oil plant (Ricinus communis). Interestingly, the poison contained two forms of isomers, cis and trans. This suggests that the sample was heated, which is needed to transform the isomers from one to the other. Despite several plants existing in South Africa that are capable of containing this compound, only the castor oil plant currently grows near Kruger cave, making it the most likely source of the ingredient.
However, you may be thinking, didn’t I mention how the components of the castor oil plants are not necessarily toxic by themselves and can, in fact, be used for medicinal purposes? Hence, the wooden spatula at the border cave does not necessarily represent poison.
By itself, it is difficult to determine if it was indeed used as a poison; however, its presence together with the two other known poisons indicates it was likely the two acids indicate the presence of a toxin.
Together, the ingredients provide the oldest evidence of a multicomponent poison. Likely heated at some point during the manufacturing process, and likely resulting in a liquid or gelatinous substance (hence why the femur was placed upright). The poison was poured into a femur quiver, into which the bone arrow tips were placed. It is possible the various poisons were combined simply because Bushmen groups often mixed different plant and arthropod ingredients together, some for their known effects, while others were added due to the inherent belief they had an effect (even if this was simply a placebo).
Another option for the multiple components may be the hunter’s desire to increase the range of animals he could hunt with the poison. As different toxins affect different animals in varying ways, perhaps by adding multiple poisons to his arrows, a greater range of game could successfully be hunted. Regardless of the reasoning for manufacturing multi-component poisons, the poison arrows from Kruger cave are the oldest multicomponent poisons, predating the Egyptian examples by at least 3,500 years.
Dr. Bradfield and his colleagues analyzed residue found inside a femur quiver from Kruger Cave. The analysis revealed the residue to be a multicomponent poison, the oldest of its kind, created from three different plants, two of which are known for their effects on the heart, including disturbing the heart’s rhythm and causing heart failure.
The existence of the poison indicates a relatively sophisticated botanical knowledge and understanding of plant pharmacology by southern African Bushmen over 7,000 years ago.
What are your thoughts on the heart-stopping poison, and why do you think it was left behind in the cave? Perhaps it had dried up before they had a chance to use it.
References
Bradfield, J., Dubery, I. A., & Steenkamp, P. A. (2024). A 7,000-year-old multi-component arrow poison from Kruger Cave, South Africa. iScience, 27(12).
Bradfield, J., & Lotter, M. G. (2021). The Current Occupation of Kruger Cave, A Later Stone Age Site, South Africa. Journal of Contemporary Archaeology, 8(1).
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