When imagining our early human ancestors in prehistoric Africa hundreds of thousands of years ago, one might envision trekkers plodding across a savanna, baking under an equatorial sun.
Research, however, suggests that our species’ unique strengths – creativity, cooperation and adaptability – may have been honed in a very different environment. Our team of archaeologists has uncovered a story in which mountainous landscapes played a central role in making us human.
Today, those of us who like to explore mountains have technical gear and conveniences like GPS safety beacons, water filters and raincoats that pack down small. Without this, we’d be lucky to last one night in some places. How did early humans not only survive, but thrive in these landscapes?
This question inspires my archaeological research in Lesotho’s Maloti-Drakensberg Mountains. Since 2023, I have led an international team of excavators at Likonong, a collapsed rock shelter in a remote area of eastern Lesotho.
Our findings reveal that Likonong is the oldest known archaeological site in these mountains and an incredible case study in human adaptation.
Likonong was first discovered in 1995. I visited the site as a graduate student in 2015 and returned in 2023 with my PhD to begin excavations. I hoped that Likonong would be older than Melikane, which, at 83,000 years old, was Lesotho’s earliest known site at the time. When my team started finding stone tools that looked 100,000 years older, I realised this site was more important than I’d imagined.
Our excavations have found evidence of people visiting Likonong beginning at 242,000 years ago, and making regular, longer visits by 144,000 years ago. Previously, archaeologists suspected that sustained occupation in highland Lesotho was unlikely before the climate warmed during the Last Interglacial, 130,000 years ago. Instead, our research shows that early humans thrived here during an ice age, possibly by relying on one another.
The setting
We’re no longer in an ice age, but living in Lesotho still requires teamwork. At Likonong, we’re hours away from the nearest paved road or medical clinic, excavating on a precarious, erosive slope above a ravine. We sleep in tents, filter water, and cook for ourselves. The sun sets at 5pm, giving way to unbearably cold and windy nights. Tinder is scarce on the barren, treeless landscape. At an elevation of 1,800 metres, an oncoming storm inevitably means snow.
Making the excavation work requires cooperation from each member of the team. While some of us dig, others sieve excavated sediment in search of artefacts. Someone heats up the tea kettle when the late afternoon chill sets in, and someone else knocks down the metre-long icicles that collect on the shelter roof.
It simply isn’t possible to survive in this environment without help, which might be why earlier hominins – members of the human lineage – didn’t stand a chance. While a few isolated hand axes suggest that a few brave individuals attempted to survive here, we haven’t discovered their bones or their campsites.
In contrast, 50km north-west of Johannesburg (about 600km from our site), an underground labyrinth of limestone caves known as the “Cradle of Humankind” traces human evolution back nearly 4 million years, to a time before the first stone tools or manmade fire. Hominins thrived in these lowlands and the equatorial highlands of east Africa, but the earliest occupations at Likonong didn’t occur until after the emergence of our species.
When were people there, and what were they doing?
In our excavations at Likonong we used several methods to get a clearer idea of how humans learned to adapt and survive at the site. One, called magnetic susceptibility, measures how easily sediment can be magnetised. We use it as an indirect measure of fire use, which we expect to have been frequent for anyone using Likonong as a home base. Fire is critical not only for warmth, but also for cooking, making tools, and advanced technologies like adhesives. The earliest occupations dating to around 242,000 and 214,000 years ago have relatively low magnetic susceptibility values, implying limited burning and that humans were not staying at the site for very long.
Evidence for human occupation between 214,000 and 144,000 years ago is minimal. But then something changed. Signs of human activity increased so much that we named this layer “Lower Crazy Town” because of the stone tools and charred bone gushing from its layers. We believe that this is the point at which humans started using Likonong as a more permanent home base. Families built hearths on top of hearths, cooked food, made tools, and slept in the shelter. Not long after, burning was so frequent that the earth itself turned red. Instead of building the occasional fire, humans structured their lives around this technology.
Crucially, surviving in the highlands at this time (144,000 years ago) would have been even more challenging than at 242,000 years ago. Between 190,000 and 130,000 years ago, a period of time known as the Penultimate Glacial Period, the world was plunged into an ice age. Temperatures dropped more than 6ºC, lush forests disintegrated into windswept grasslands, and glaciers capped the mountains’ highest peaks.
So why couldn’t Likonong’s first visitors figure out how to survive at the site for longer periods of time? We don’t believe they were any less intelligent than the later occupants.
We think they left because they didn’t share information, collaborate, or cooperate with one another. Innovations don’t happen in a vacuum. Cultural knowledge relies on mechanisms for both preserving and spreading information, such as far-ranging social networks and oral tradition. One small change – for example, more frequent fire use – could have led to profound technological advances by creating an environment for information sharing and group cohesion.
The humans who ventured into the highlands 144,000 years ago would have been under extreme environmental pressures. If they chose to rely on one another, sharing their skills and experiences around a fire, they may have jump-started a cascade of changes that shaped us into the adaptable species we are today.
During my first season as a principal investigator at Likonong, I was constantly texting my colleagues for help and advice. Which sieve should we use? What kind of stone was that? How do I resolve personal conflicts with team members? I’m lucky they picked up the phone. Without their help, I probably would have quickly left the site, too – just like the first humans to venture into the highlands, 242,000 years ago.
This article was originally published on The Conversation. Read the original article.
