Early art on ostrich eggs reveals insights into ancient human thought

Jenn Hoskins
13th February, 2026

Early art on ostrich eggs reveals insights into ancient human thought

Tracing an engraved ostrich eggshell fragment, normalizing the lines according to stable visual properties, and extracting key variables provides the quantitative data needed to reveal the structured 'geometric grammar' used by early Homo sapiens.

Image adapted from: Decembrini et al. / CC BY (Source)

Key Findings

  • Engravings on ostrich eggshells from South Africa, dating back 60,000 years, show evidence of complex thought
  • The patterns weren't random scratches but systematically used geometric features like parallelism and repetition
  • These engravings reveal a ‘geometric grammar’ – a rule-based system for organizing visual forms, indicating early symbolic expression
The question of when humans first developed ‘modern’ behaviour – encompassing complex thought, symbolic expression, and cultural practices – has long been a central debate in archaeology. Identifying the origins of these behaviours is difficult, as they don’t fossilize directly. Instead, archaeologists rely on interpreting artifacts from the past. For a long time, the European archaeological record dominated this discussion, with certain finds used as benchmarks for ‘modernity’[2]. However, this created a bias, as the African continent, widely considered the birthplace of Homo sapiens, often presented a different, less complete picture. Recent discoveries in southern Africa have challenged this Eurocentric view, suggesting that key aspects of modern behaviour emerged earlier than previously thought[3][4]. A new study conducted by researchers at the University of Bologna and Sapienza University of Rome[1] focuses on engraved ostrich eggshell (EOES) fragments discovered at Diepkloof Rock Shelter in South Africa, dating back approximately 60,000 years. These fragments, associated with the Howiesons Poort (HP) technocomplex, have been known for some time, with previous research establishing their intentional marking and repetitive patterns[3]. However, the new research goes beyond simply identifying the engravings; it seeks to quantify and analyze the geometric and spatial organization within them. The core problem the study addresses is whether these markings are simply random or represent a deliberate system of graphic representation – a structured way of organizing visual information. To do this, the researchers didn’t focus on what the patterns look like, but rather on their underlying geometric properties. They examined ‘non-accidental properties’ – features that remain consistent regardless of how the eggshell fragment is viewed, such as the curvature of lines, whether lines run parallel to each other, and where lines connect. They also measured precise angles and spatial arrangements. The analysis revealed that the HP engravings systematically employ specific geometric features. The patterns aren’t haphazard; they demonstrate a consistent use of parallelism, iteration (repeating elements), alignment, and rotation. Crucially, the researchers established empirical thresholds – objective limits – to determine what constituted a meaningful geometric feature, avoiding subjective interpretation. For example, lines were considered parallel if their angular difference fell within a specific range. This quantitative approach highlights that the creation of these engravings required complex cognitive operations. The makers of these tools weren’t simply scratching lines onto shells. They were actively organizing visual forms, embedding geometric principles within a spatial layout. This involved mentally iterating lines, aligning them with precision, rotating them to create intersections at specific angles, and translating (moving) elements within the overall design. This research builds upon earlier findings from Blombos Cave, also in South Africa, where engraved ochre pieces dating back as far as 75,000-100,000 years ago were discovered[4]. These discoveries already suggested that symbolic thought and tradition were present in the region earlier than previously believed. The Diepkloof EOES, however, offers a larger sample size and allows for a more detailed analysis of the engravings themselves. The new study provides stronger evidence for the complexity of these early symbolic expressions, demonstrating a level of geometric organization not previously recognized. Interestingly, the study’s findings resonate with research in other fields. Kant’s work on Euclidean geometry, which proposes that humans possess an innate understanding of spatial relationships[5], provides a theoretical framework for understanding these intuitions. Research on the Mundurucu people of the Amazon has shown that even without formal mathematical education, individuals demonstrate an intuitive grasp of Euclidean principles like the sum of angles in a triangle[5]. This suggests that the ability to perceive and organize geometric forms is a fundamental aspect of human cognition, potentially present across different cultures and time periods. The HP EOES engravings, therefore, represent an early material expression of this inherent capacity for geometric thought. They aren’t simply decorative; they reflect a system of rules through which Homo sapiens organized visual information, providing insights into the cognitive foundations of structured graphic behaviour.

EcologyEvolution

References

Main Study

1) Earliest geometries: A cognitive investigation of Howiesons Poort engraved ostrich eggshells

Published 11th February, 2026

https://doi.org/10.1371/journal.pone.0338509

Related Studies

2) The origin of modern human behavior.

Journal: Current anthropology, Issue: Vol 44, Issue 5, Dec 2003

3) From the Cover: A Howiesons Poort tradition of engraving ostrich eggshell containers dated to 60,000 years ago at Diepkloof Rock Shelter, South Africa.

https://doi.org/10.1073/pnas.0913047107

4) Engraved ochres from the Middle Stone Age levels at Blombos Cave, South Africa.

https://doi.org/10.1016/j.jhevol.2009.01.005

5) Flexible intuitions of Euclidean geometry in an Amazonian indigene group.

https://doi.org/10.1073/pnas.1016686108


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