(CN) - Anthropologists at the Smithsonian's National Museum of Natural History and a team of international collaborators discovered that early humans in East Africa displayed sophisticated behavior, trading and tool crafting tens of thousands of years earlier than previously assumed.
Middle Stone Age humans began using color pigments, creating sophisticated tools and trading with distant groups about 320,000 years ago, a period matching the oldest known fossil record of Homo sapiens. These behaviors replaced the technologies and ways of life of Early Stone Age humans, whose practices had been in place for hundreds of thousands of years.
In a statement, Smithsonian researchers referred to these discoveries as “milestones in humans' evolutionary past.”
In an earlier era, experts say humans crafted large, unrefined tools resembling all-purpose stone axes. But new research has uncovered advanced, smaller tools that had been more carefully crafted by later groups. Many of the tools were specialized, designed to be attached to a shaft and potentially used as projectile weapons, while others were shaped as scrapers or needles.
The archaeological evidence of these tools comes from a region in southern Kenya called the Olorgesailie Basin. The first signs of human life in the Basin appear about 1.2 million years ago.
The Smithsonian team also discovered black and red rocks at the sites, along with evidence that the rocks had been processed for use as coloring material.
"We don't know what the coloring was used on, but coloring is often taken by archaeologists as the root of complex symbolic communication," Rick Potts, director of the National Museum of Natural History's Human Origins Program, said in a statement. "Just as color is used today in clothing or flags to express identity, these pigments may have helped people communicate membership in alliances and maintain ties with distant groups."
The studies indicate that these human behaviors developed in a period of extreme climate and geological volatility in which it would have been difficult to rely on consistent access to resources.
In this Middle Stone Age period, earthquakes remodeled the landscape and climate fluctuated between wet and dry conditions. Ancient tool crafting innovation, trading networks and early social communication would have helped early humans survive and obtain the resources they needed despite unpredictable conditions, the scientists say.
Environmental instability would have presented significant challenges to inhabitants of the Olorgesailie Basin. According to researchers, these conditions would have prompted human groups to adapt their tools and social structures to improve the chances of securing resources during times of scarcity.
"This change to a very sophisticated set of behaviors [required] greater mental abilities and more complex social lives," Potts said. “[The change] may have been the leading edge that distinguished our lineage from other early humans.”
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