125,000-Year-Old Stone Points in Saudi Arabia May Be Poisoned
Stone points from a 125,000-year-old lakeshore in Saudi Arabia carry residue from a toxic tree, possibly the oldest poisoned weapons, Science reports.
Archaeologists working in southern Saudi Arabia report that stone points from a site dated to 125,000 years ago carry chemical residue from a toxic tree, which may make them the oldest known poisoned hunting weapons. The study was published Thursday (Nov. 12) in the journal Science.
Study co-author Chris Clarkson, an archaeologist at the Max Planck Institute of Geoanthropology in Germany and Griffith University in Australia, told Live Science the points would be substantially older than poisoned arrowheads recently identified in South Africa, which date to around 60,000 years ago. He added that the team has not shown how the poison was prepared or whether it worked, so he describes the finds as potentially the oldest evidence rather than an established first.
A vanished lake in the Empty Quarter
The site is called ‘Uruq Aljelibah, which geologist Frans van Buchem of the King Abdullah University of Science and Technology says means “sand dunes of a watering hole.” Today it lies in the Empty Quarter, one of the hottest, driest deserts on Earth. The researchers found that it was once the shore of a freshwater lake about 130 square miles (340 square kilometers) across and up to 95 feet (29 meters) deep.
Fossils show the lake supported hippopotamuses, buffalo, ostriches, camels, gazelles and oryx, along with palms, reeds, trees and shrubs. Early modern humans likely used these animals and plants for food and other resources.
Thousands of tools and one toxic tree
The team found more than 5,500 stone artifacts, along with well-preserved plant material such as fibers, resins and wood. Several stone points showed impact damage consistent with hunting large animals, and microscopic analysis found traces of animal tissue near their tips. The tools clustered where animal bones were found, which the study takes as a sign that the lakeshore was a focal point for hunting and processing game.
Several points also carried chemical residues linked with the arrow poison tree (Acokanthera schimperi), which is native to eastern and central Africa and southern Arabia. African hunters have used extracts of the plant to coat spear tips and arrowheads to paralyze or kill game.
How hunters using such poison avoided harming themselves when eating the meat is unclear. Clarkson noted that the effect of a poison depends on the substance, the dose and how it enters the body, and that hunters throughout history are known to sometimes cut away the meat around the wound.
What it means for early human technology
Clarkson said researchers have often underestimated early human technology because so much of it was organic and has vanished. In his reading, the people at this site combined stone with wood, plant fibers, resins and possibly toxic substances.
Two researchers not involved in the work offered comment. Eleanor Scerri, an archaeologist at the Max Planck Institute of Geoanthropology, called the amount of evidence remarkable, from traces of how spear tips were hafted (fixed to a handle) up to the match between hunting tools and the bones of animals such as hippos. Jeffrey Rose, a Paleolithic archaeologist at the University of Algarve in Portugal, said sites in Arabia with both stone tools and animal bones are rare, and that some flakes fit back together, so the tools were made on the spot.
No human remains turned up. The researchers still suspect the site belonged to modern humans (Homo sapiens), since the species had already spread out of Africa and was present in Southwest Asia at the time. The finds add to evidence that wetter periods in Arabia opened migration corridors between Africa and Asia.
Limits and next steps
Rose cautioned that all the stone artifacts were collected from the surface, and none came from the layers that were dated. In his words, the 125,000-year date belongs to the lake, and for the tools it is only a maximum age. He said future work should look for artifacts sealed in lake beds, which is hard in Arabia because wind has stripped most sites down to surface scatters.
Clarkson wants to return to find more fossils, including human ones, and to push the chemical analysis further to identify which toxic substances were used and how they were prepared.
Source: Live Science
