For decades, anthropologists believed that early hominins — our distant ancestors roaming Africa over a million years ago — had a limited toolkit. They were thought to have used simple stone tools, occasionally using bones opportunistically but never systematically shaping them. A new study upends that view.

The study found strong evidence that populations purposefully crafted bone tools 1.5 million years ago. They used knapping methods similar to those employed for stone tools. This is all the more impressive as it suggests a culture of learning and transmission of knowledge, as the methods for shaping bone would have required teaching and refinement over generations.

Olduvai Gorge

Olduvai Gorge is one of the most famous archaeological sites in the world. Located in northern Tanzania, this deep ravine has preserved nearly two million years of early human history. It offers important insights into the evolution of our ancestors. Discovered and extensively excavated in the mid-20th century, Olduvai has yielded some of the earliest known stone tools, as well as fossils of early hominins like Homo habilis and Homo erectus.

As it turns out, Olduvai Gorge still has much more to give.

In the new study, researchers led by Ignacio de la Torre from the Spanish National Research Council (CSIC) identified 27 distinct bone tools. Each of these tools displays a level of craftsmanship that suggests deliberate shaping. Some of these tools were massive and elongated, up to 38 centimeters long, making them far larger than most known bone tools from later periods. The flaking scars suggest that the bones were worked in multiple steps — first removing large flakes to shape the tool, then making smaller modifications to refine its edges.

The choice of material is also telling. The majority of these tools were crafted from elephant and hippopotamus bones. These large, thick bones were deliberately selected, likely because they provided a sturdy, durable material that could withstand heavy use.

All of this points to a striking idea: whoever made them knew what they were doing.

Why bone tools are so important

For years, researchers have debated when complex thought and culture developed in early hominins. The ability to recognize that a bone, just like a stone, could be shaped into a useful tool represents a significant leap.

Until now, systematic bone tool production was thought to be a much later development, associated with sites from around 400,000 years ago. The fact that bone tools don’t preserve as well as stone tools may explain the paucity of such artifacts. But this new evidence suggests that early toolmakers already had this ability more than one million years earlier.

In other words, these hominins weren’t just surviving. They were innovating. They were also passing this knowledge onto the next generation. This suggests an emerging culture of teaching and learning, a foundational trait of later human societies.

But if they developed bone tools so early on, why haven’t we found more evidence of them?

One reason may be preservation bias. Bone is an organic material that decomposes more readily than stone. Many ancient bone tools may have simply been lost to time. Another possibility is that this innovation was location-specific — perhaps early hominins in this particular region of East Africa experimented with bone tools, but the idea didn’t spread widely or endure long-term.

Yet another possibility is that we simply haven’t been looking closely enough. Now that we know these tools exist, archaeologists may begin re-examining old collections with fresh eyes, looking for evidence of early bone tool production that might have gone unnoticed.

What were the tools used for?

There’s still a fair bit of speculation about what the tools were actually used for.

The sheer size and weight of some of the tools suggest that they were used for heavy-duty tasks — perhaps as hammers, anvils, or chopping implements. Others, with their sharp edges, could have been used for butchery, helping hominins extract meat and marrow from carcasses more efficiently.

The presence of numerous hippopotamus bones at the site suggests that these animals were taken from the local ecosystem and were likely an important food source for the hominin populations. It’s possible that early humans developed bone tools specifically to process these large animals — cutting through tough hides, breaking open bones for marrow, or even stripping meat from carcasses.

It’s also unclear exactly which hominins produced these tools.

Homo habilis, likely the earliest known human species, inhabited Olduvai Gorge around 1.9 million years ago (mya). They were later joined by the robust australopithecine Paranthropus boisei, which appeared around 1.8 mya, followed by Homo erectus at 1.2 mya. Much later, Homo sapiens, who evolved approximately 300,000 years ago, are believed to have occupied sites in the gorge as recently as 17,000 years ago.

But one thing’s for sure. Our ancestors weren’t just tool-users. Even 1.5 million years ago, they were problem-solvers, experimenters, and, in their own way, engineers of the ancient world.

The study has been published in the journal Nature.