The first social network
Deep inside Porc-Epic Cave, located 3 km south of Dire Dawa, archaeologists uncovered early evidence of personal expression and social identity. The finds were hundreds of opercula—the trapdoor-like structures that seal the opening of a snail's shell—from the terrestrial gastropod Revoilia guillainopsis. These small, disc-like objects have a natural central perforation, making them ideal for stringing. Analysis of their context indicates they were not a food source and did not accumulate naturally. Instead, Middle Stone Age people collected and used them as beads around 60,000 years ago.
Microscopic examination of the opercula reveals they were stained with red ochre and show signs of wear from being suspended and rubbing against skin or clothing for an extended time. This use as personal ornaments represents one of the earliest examples of symbolic behavior in Homo sapiens. The beads were symbolic objects; they were a medium for communication, likely signaling identity, status, or group affiliation in a world without written language. The consistent use of these specific opercula suggests a shared cultural and symbolic meaning among the people who inhabited the cave.
The cave itself is situated 140 meters above the Dächatu wadi, at the base of a Jurassic limestone cliff. The location provides a commanding view of the surrounding landscape, a strategic position for the hunter-gatherers who occupied it for thousands of years.
A region of meaning
The story of the beads extends far beyond the cave walls. The shells themselves originated from the Red Sea or the Gulf of Aden, over 60 kilometers away. Transporting these non-functional items across such a distance demonstrates that early humans had established exchange networks or undertook long seasonal journeys. Objects were valued purely for their aesthetic and symbolic qualities. Obsidian, a volcanic glass used for making sharp tools, was also brought to the cave from sources up to 150 km away, such as the outcrops at Ayelu.
Porc-Epic Cave is significant for its beads but also for its industrial-scale ochre processing. Excavations have uncovered more than 40 kilograms of ochre, consisting of 4,213 individual pieces, making it the largest Middle Stone Age ochre collection in East Africa. Archaeologists also found 21 distinct ochre processing tools, including grindstones made from various rock types like basalt and limestone.
The inhabitants of Porc-Epic produced ochre powders of different colors and coarseness. Fine-grained red powders, high in hematite, were consistently produced over a period of at least 4,500 years and were likely used for symbolic activities like body painting. The decision to coat the shell beads in this carefully prepared red pigment added another layer of symbolic meaning, connecting personal identity to a culturally significant color.