Diepkloof Rock Shelter: Engraved Ostrich Eggshell Flasks

Diepkloof Rock Shelter, a sandstone overhang near Elands Bay on South Africa’s west coast, holds one of the most important collections of early decorated objects in the world. Excavations there recovered hundreds of fragments of ostrich eggshell engraved with geometric patterns, most dating to roughly 60,000 years ago. Because the eggs seem to have served as water flasks, the find shows early Homo sapiens decorating everyday objects according to shared, long-lasting rules.

The site and its excavation

The shelter lies in the Western Cape, in a cliff overlooking the Verlorenvlei, a coastal wetland about 180 km north of Cape Town. Its deep deposits span much of the Middle Stone Age, the long period of African prehistory, from about 300,000 until roughly 40,000-30,000 years ago, in which people made flake and blade tools and gradually developed new technologies.

Archaeologist John Parkington of the University of Cape Town first tested the site in the 1970s. Large-scale excavation began in 1998 under a South African and French team led by Parkington, Jean-Philippe Rigaud and Pierre-Jean Texier, with Cedric Poggenpoel among the excavators. Work over the following decade exposed a sequence of layers several metres thick.

Among the finds were stone tools of two famous southern African industries: the Still Bay, known for finely made leaf-shaped points, and the later Howiesons Poort. It was in the Howiesons Poort layers that the engraved eggshell appeared in large numbers.

The people who used the shelter lived by hunting, gathering plants and, at times, collecting shellfish. During much of the Middle Stone Age sea levels were lower than today, so the coastline lay farther west than it does now, and the distance to the shore changed as the climate shifted between warmer and colder phases.

The sequence at Diepkloof is unusually well preserved. Hearths, ash lenses and thin occupation surfaces lie one above another, allowing archaeologists to follow changes in technology and behaviour layer by layer rather than in broad blocks of time.

The Howiesons Poort

The Howiesons Poort industry is named after a rock shelter near Makhanda (formerly Grahamstown) in the Eastern Cape, where it was first described. Its makers produced small, carefully shaped stone pieces, especially crescent-shaped “segments” with one blunted edge. These were probably mounted in wooden or bone hafts as parts of composite weapons, perhaps arrows or light spears.

The industry is found at many sites, including Klasies River, Sibudu Cave and Rose Cottage Cave. Luminescence dating by Zenobia Jacobs and colleagues, published in 2008, placed it between about 65,000 and 60,000 years ago across southern Africa. A separate programme of dates for Diepkloof itself, led by Chantal Tribolo, suggested a longer and older sequence there, and the two chronologies have not been fully reconciled.

The engraved eggshells

The first study of the Diepkloof eggshells, published in 2010 by Texier and colleagues, described 270 engraved fragments. Further excavation and study raised the total to several hundred, making it by far the largest assemblage of its kind from this period.

The engravings were cut with a sharp stone point into the outer surface of the shell. Researchers identified a small set of recurring motifs:

• Hatched bands: two long parallel lines enclosing many short crossing strokes, the most common design.
• Parallel or sub-parallel lines: sets of lines running side by side, sometimes converging.
• Cross-hatching: lines crossing to form a grid or net pattern.

These motifs were not random scratches. They were repeated on fragment after fragment, and the dominant design changed over time, with hatched bands more typical of earlier layers and parallel lines more common later. This suggests a tradition that people learned, passed on and gradually modified.

How the engravings were studied

The research team examined every fragment under magnification, recording the depth, width and direction of each groove. This showed that most lines were cut with repeated strokes of a pointed stone tool along the same path, a slow and deliberate process rather than quick scratching.

Because the fragments are small, no complete decorated egg has been reconstructed. Instead, researchers grouped pieces by motif, thickness and curvature to estimate how the designs were laid out. On some fragments the hatched bands seem to have run around the body of the egg, much as decoration does on recent San flasks.

The study also showed that the engraved pieces were spread through many successive layers, not concentrated in a single episode. That pattern is what turned the find from a curiosity into evidence for a tradition: generations of people, over thousands of years, chose from the same small repertoire of designs.

Engraved eggshell of similar age has since been reported from other southern African sites, including Klipdrift Shelter on the southern Cape coast and Apollo 11 Cave in Namibia. The practice was therefore not unique to Diepkloof, although no other site has produced a collection of comparable size.

Water flasks

Several fragments come from the rim of a deliberate opening cut into the egg. An ostrich egg holds around a litre of liquid once emptied, and in recent centuries San hunter-gatherers of the Kalahari and Namaqualand used them as water flasks, stoppering the hole with grass and sometimes burying full shells as caches for later use. Some of these historical flasks were also engraved.

The Diepkloof evidence suggests the same practice is very ancient. Carrying water would have helped people move across dry landscapes, and a decorated flask may also have identified its owner or the group to which the owner belonged. This last idea is an interpretation, but it is consistent with how decorated objects are used in many societies.

What the patterns may mean

Earlier engraved objects exist, most famously the cross-hatched ochre pieces from Blombos Cave on the southern Cape coast, dated to around 75,000-100,000 years ago. What makes Diepkloof stand out is the quantity and consistency of the engravings and the long span of time over which the same graphic conventions were maintained.

Many archaeologists interpret this as evidence for symbolic communication: a set of shared signs whose meaning was understood within a community. Others caution that decoration does not necessarily equal symbolism and that we cannot recover what the marks meant to their makers. Either way, the shells show planning, skill and social learning.

The eggshells also fit a wider pattern. Southern African sites of this period, such as Sibudu Cave in KwaZulu-Natal, have yielded shell beads, heat-treated stone, ochre processing, plant bedding and complex hafted tools, all part of the debate about when and how fully modern human behaviour developed.

Some researchers link these innovations to growing populations and wider social networks, in which sharing recognisable designs would have helped people identify allies and partners across large areas. Others stress that the Howiesons Poort was followed by a period in which such innovations appear less often, showing that cultural change was not a simple one-way progression.

Timeline

• c. 300,000 years ago: The Middle Stone Age begins in Africa.
• c. 75,000-70,000 years ago: The Still Bay industry is in use across southern Africa, including at Diepkloof.
• c. 65,000-60,000 years ago: The Howiesons Poort industry is widespread; most Diepkloof engraved eggshells date to this phase.
• 1973: John Parkington carries out early test excavations at Diepkloof.
• 1998: Large-scale excavations begin under a South African and French team.
• 2010: Texier and colleagues publish 270 engraved fragments in the Proceedings of the National Academy of Sciences.
• 2013: A larger study of the expanded collection is published, analysing motifs and their change over time.

By the numbers

Why it matters

Diepkloof shows early Homo sapiens adding consistent designs to practical objects, long before anything comparable in Europe. Together with sites such as Blombos Cave and the painted stones of Apollo 11 Cave, it places southern Africa at the centre of research into the origins of symbolic culture, tens of thousands of years before the Lascaux cave paintings.