When we think of the last Ice Age — roughly 26,000 to 19,000 years ago — we often picture vast sheets of ice blanketing Europe and North America. But far to the south, in what is now coastal South Africa, a very different but equally dramatic landscape was taking shape.
As global sea levels fell by up to 125 meters, enormous stretches of the continental shelf emerged from the sea, creating the Palaeo-Agulhas Plain — an expansive grassland teeming with life, much like today’s Serengeti. This lost world supported large herds of animals and the hunter-gatherer communities who relied on them for survival.
Now, thanks to ongoing excavations at Knysna Eastern Heads Cave 1, perched 23 meters above today’s sea level along South Africa’s southern coast, we have an unprecedented glimpse into how humans adapted to this changing world at the close of the Ice Age.
A window into a changing world
Led by Dr. Naomi Cleghorn from the University of Texas, excavations at Knysna began in 2014 and have revealed that people used the cave repeatedly over the past 48,000 years. During the Ice Age, the coastline lay some 75 kilometers further out to sea — where the vast Palaeo-Agulhas Plain stretched to the horizon.
When sea levels dropped and the climate cooled, people who once foraged for shellfish turned their attention inland, relying more on hunting and land-based resources.
In a recent study, my colleagues and I examined stone tools from this site dating to around 19,000–18,000 years ago. These tools tell a story not only of survival but of innovation, learning, and connection among communities spread across southern Africa.
The Robberg tradition
The tools we found belong to what archaeologists call the Robberg Industry — one of southern Africa’s most distinctive Ice Age technologies. These small, sharp stone bladelets were likely parts of composite hunting weapons, such as barbed arrow tips used to bring down migrating game on the grassy plains below.
The Robberg toolkit appears across South Africa, Lesotho, and Eswatini, showing that people were sharing ideas and techniques across vast distances — much like how knowledge spreads today.
Most of the Knysna tools were crafted from locally available quartz, prized for its sharp edges despite its tendency to fracture unpredictably. Intriguingly, some tools were made from silcrete — a material that had to be heat-treated to improve its flaking quality. This indicates sophisticated craftsmanship: heat-treating silcrete for toolmaking is a skill South Africans have mastered since at least 164,000 years ago.
However, silcrete isn’t found near Knysna. The closest sources are in the Outeniqua Mountains, over 50 kilometers inland. Whether the cave’s occupants traveled these distances themselves or traded with other groups remains an open question.
A temporary Ice Age camp?
Compared to other sites, Knysna Eastern Heads Cave 1 holds relatively fewer tools in the younger layers, suggesting that people may have used the cave as a short-term shelter rather than a permanent home during the harshest Ice Age conditions.
Did they stop here while tracking game herds across the plains? Or gather here seasonally to share food, stories, and knowledge? Stone tools alone can’t answer all our questions, but they are invaluable pieces of the puzzle.
Echoes of humanity’s deep past
What’s clear is that Ice Age humans were not so different from us. They used complex tools, shared skills over great distances, made art and music, and connected with other communities — even as glaciers dominated far-off continents.
Sites like Knysna Eastern Heads Cave 1 remind us that our human story is one of resilience, innovation, and connection that stretches back tens of thousands of years.
