Obsidian Tools Discovered In Kenya Suggest Human Innovation Took Place Much Earlier Than Once Thought

New research suggests that early humans were creating useful obsidian tools in what is now known as Kenya, and coming up with innovations on the ubiquitous hand ax at an unusually early time in human history.

In a trio of studies published in the journal Science on Thursday, a multinational team of researchers described the ancient items they found in the Olorgesailie Basin in Kenya, including stone tools used by humans during the Early Stone Age. These tools were teardrop-shaped axes with sharp edges and rounded ends that might have been used to chop wood, dig for water, or cut up the carcasses of animals, according to NPR.

The animals are believed to have been larger creatures, such as the ancestors of present-day wild pigs, elephants, and hippos, and due to the size of these animals in relation to the size of the axes, researchers believe that early humans in the area might have feasted on dead animals, effectively scavenging instead of actually hunting live creatures. Meanwhile, the hand axes used to chop the carcasses might have been used for hundreds of thousands of years, from 1.2 million years to 500,000 years ago, before humans started crafting items mostly made out of obsidian, tools that were lighter, flatter, and more useful than the stone axes before them.

“We see a smaller technology, a more diverse series of stone tools,” said Rick Potts, director of the Smithsonian Museum of National History’s Human Origins program, who led the first of the recently published studies.

According to Phys.org, the smaller and newer tools included points and blades and were primarily made out of the volcanic glass obsidian, as opposed to the volcanic basalt used in making the aforementioned axes. George Washington University anthropologist Alison Brooks, an author on the second of the three studies, said that the tools allowed early humans to switch from scavenging to hunting based on analysis of the animal bones found at the Kenya site. She added that the people who used those tools were now consuming rabbits, springbok, birds, fish, and other smaller animals that were similar in size to their modern-day descendants.

As the obsidian tool innovation could have taken place 320,000 years ago, this suggests that humans were making technological advances and kicking off the Middle Stone Age several tens of thousands of years earlier than researchers had once thought. This, according to the researchers, might have been a result of several events, including earthquakes and alternating droughts and heavy rains, as humans during those times socialized with those from other groups, teaming up to adjust to the harsh conditions.

Of particular interest to the researchers was the distance which early humans traveled to gather the obsidian to craft their innovative new tools. While their ancestors traveled only up to 2.5 miles to gather the volcanic rock for their stone axes, Potts pointed out that the makers of the newer tools traveled much greater distances to gather materials, possibly in an early form of trading or “social networking” between multiple groups of people.

“That black obsidian, that rare rock was being transported, brought in in chunks, from 15 to 30 miles away. We have a couple of rocks that were brought from up to 55 miles away.”

Potts added that those people didn’t just “chip rocks as they [went],” but instead carried the obsidian with them as they headed back to Olorgesaile, and only making the tools once they had already returned home.

In addition to the use of obsidian tools and the trading of resources between groups of early humans, the researchers also dug up proof that could suggest the people of Olorgesaile were extracting pigment from “brightly colored” red and black rocks they brought back from their long trips to collect materials. Paleoanthropologist Marta Mirazon Lahr, who was not involved in the studies, told NPR that this could be the earliest evidence of humans extracting pigments.