Ornaments have been worn by humans since the dawn of civilisation. They have been used to express our individuality and to signify relationships. From around 75,000 years ago beads begin to appear and from about 50,000 years ago they started to be made from ostrich eggshells. Ostrich eggshell beads are among the most commonly found archaeological artefacts in Africa.
Ostrich eggshell beads as currency
But these eggshell beads were not only used to adorn our bodies. A study published in March 2020 suggests that they were used as gifts to create a sense of indebtedness across groups of hunter-gatherers. Around 33,000 years ago they created a social safety net across a large part of southern Africa with ostrich eggshell beads as its currency.
Ostriches lived in dry, flat savannahs but not at the rock shelters where many of the beads were found. The assumption is that inland residents would have made the beads. The beads were then passed on from group to group over long distances. The discoveries show that this went on for tens of thousands of years.
Hunter-gatherer exchange networks exist today. Their purpose is to reduce survival risks by creating mutual support through gift-giving. The Ju/’hoãn people in southern Africa’s Kalahari Desert use this system to this day and are the basis for modelling how prehistoric hunter-gatherer groups might have operated. The practice of gift-giving for mutual benefit is called hxaro. Hxara partners live quite often live as far apart as 100km in areas with complementary resources.
Brian Stewart of the University of Michigan in Ann Arbor and his colleagues have concluded that the beads were given as gifts to create goodwill and unity across groups of hunter-gatherers. They suspect that groups in resource-rich areas such as the coastal Lesotho highland could have provided food to their inland counterparts where food and other resources were scarce, especially during times of drought. Whatever was given in exchange for the beads probably did not preserve through the millennia.
Determining the origin of the beads
The age of the beads was determined through carbon dating. This technique, however, cannot determine origin. For this purpose, an analysis of strontium isotopes in the ostrich shell beads that is compared to strontium isotopes in plant, soil, water and mammal teeth samples from different regions is used. Different geographical regions show different signature strontium concentrations which makes it possible to determine location.
Examining the size of beads also plays a role in determining age. Beads found at hunter-gatherer sites are usually smaller than those found at herder sites. As herding in Africa only started about 2000 years ago, sites with larger beads tend to be younger than those will smaller beads.
“I suspect these practices began long before 33,000 years ago, and not just in southern Africa.”
Stewart’s research matches the idea that different hunter-gatherer groups often contain in-laws and unrelated individuals who maintain contact for the benefit of all. Stewart speculates that this ancient exchange network is much more widespread, both historically and geographically by saying “I suspect these practices began long before 33,000 years ago, and not just in southern Africa.”