A prehistoric “factory” discovered in Tanzania could push bone tool-making back by more than a million years, indicating unexpected abstract reasoning capabilities human ancestors displayed in the remote past.
According to researchers at University College London (UCL) and the Spanish National Research Council (CSIC), about 1.5 million years ago, hominin hands fashioned the 27 ancient bone tools now preserved as fossils. The find represents the earliest significant bone tool collection ever found, particularly notable for the systematic, factory-style production methods they display.
Previous evidence indicates that hominins produced stone tools for over a million years, although archaeologists had previously never discovered bone tool collections more than 500,000 years old. The researchers involved with the discovery were also surprised to locate such a collection of tools within the same geological layer.
The First Tools
A knapping technique was used to produce the tools, where their early hominin creators chipped away small flakes to create sharp edges, similar to how earlier varieties of stone tools were made. Repurposing old techniques and applying them to new mediums demonstrates advanced toolmaking knowledge, a discovery that prompted the research team to reconsider the cognitive skills these human ancestors possessed.
“The tools show evidence that their creators carefully worked the bones, chipping off flakes to create useful shapes. We were excited to find these bone tools from such an early timeframe. It means that human ancestors were capable of transferring skills from stone to bone, a level of complex cognition that we haven’t seen elsewhere for another million years,” said Dr Renata F. Peters of UCL Archaeology, co-author of a new study detailing the findings.
the Ancient Mind and Early Tool Use
“This discovery leads us to assume that early humans significantly expanded their technological options, which until then were limited to the production of stone tools and now allowed new raw materials to be incorporated into the repertoire of potential artifacts,” said the study’s lead author, Dr. Ignacio de la Torre of the CSIC.
“At the same time, this expansion of technological potential indicates advances in the cognitive abilities and mental structures of these hominins, who knew how to incorporate technical innovations by adapting their knowledge of stonework to the manipulation of bone remains,” de la Torre added.
Researchers discovered the 27 bones in the Olduvai Gorge in Tanzania, a location of many other impactful archaeological discoveries of ancient human ancestors. Most of those bones belong to large mammals like elephants and hippos, with the hominins selecting limb bones exclusively. The density and strength of limb bones likely led to their selection.
Archaeologists also discovered raw hippopotamus bones in the same geological layer, but not elephant bone. This suggests even more advanced planning skills, as the hominins must have transported the elephant bones to the location for toolmaking. These tools represent a time when early hominins experienced one of the first technological transitions on Earth, from the Oldowan to the Acheulean age.
Technological Ages in Prehistory
Hominins developed the first stone tools between 2.7 and 1.5 million years ago during the Olodwan age. These tools and their production were simple: human ancestors used a hammerstone to chip flakes off a stone core. Hominins advanced their toolmaking technology about 1.7 million years ago as they entered the Acheulean age. At that time, they adopted the standardized knapping technique to create more intricate handles with larger production volumes.
For the first time, these fossilized tools demonstrate that hominins used advanced Acheulean techniques on bone materials at such an early time, previously seen only in fossils that formed far more recently—as much as a million years closer to the present day.
Another notable element of the find was locating such a large, centralized deposit of bone tools at this remote age. Earlier finds were rare and isolated and did not provide enough evidence to indicate systematic stone tool production by human ancestors.
Reconsidering Prehistoric Discoveries
Archaeologists identified no clear evidence of the intended use for the tools recovered at the site. Still, their shape, size, and sharpness suggest that they were likely used for processing animal carcasses to obtain food and possibly other animal-based resources.
autism
Exactly which human ancestors created the tools remains a mystery, as no hominin remains were found in situ with the fossilized bone tools. Based on earlier discoveries, two hominin species, Homo erectus and Paranthropus boisei, are known to have inhabited the area.
The researchers suggest that reevaluating prior bone tool discoveries in light of the new findings may be warranted, as the unexpected nature of the findings suggests archaeologists may have missed some insights that otherwise may be gleaned from earlier work.
The paper “Systematic Bone Tool Production at 1.5 Million Years Ago” appeared on March 5, 2025, in Nature.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted atryan@thedebrief.org, and follow him on Twitter@mdntwvlf.