The unusually large sample of 270 engraved eggshell fragments, mostly excavated over the past several years at Diepkloof Rock Shelter in South Africa, displays two standard design patterns, according to a team led by archaeologist Pierre-Jean Texier of the University of Bordeaux 1 in Talence, France.
Each pattern enjoyed its own heyday between approximately 65,000 and 55,000 years ago, the investigators report in a paper to be published this week in the Proceedings of the National Academy of Sciences.
Researchers already knew that the Howiesons Poort culture, which engraved the eggshells, engaged in other symbolic practices, such as engraving designs into pieces of pigment, that were considered to have been crucial advances in human behavioral evolution.
But the Diepkloof finds represent the first archaeological sample large enough to demonstrate that Stone Age people created design traditions, at least in their engravings, Texier says.
Evidence of intentionally produced holes in several Diepkloof eggshells indicates that ancient people made what amounted to canteens out of them, a practice that researchers have documented among modern hunter-gatherers in southern Africa.