New Stone Tools Discovery Rewrites the History of Ancient Humans
Ever since Mary and Louis Leakey’s work at Olduvai Gorge, we’ve known that East Africa served as the cradle of humanity thanks to the bones and early stone tools found at that site. The tools recovered at Olduvai are referred to as Oldowan, and they represent the earliest widespread stone tools ever manufactured. An even earlier set of tools (Lomekwian) has been discovered in Kenya, dated to 3.3M years ago, but these tools are unrelated to the later Oldowan designs that either spread across the planet beginning roughly 2.6M years ago or whose principles of manufacture were discovered independently by different hominin groups.
Up until now, and with the exception of the Lomekwian discovery, the known history of ancient hominins has indicated that the first tool-using cultures arose 2.6M years ago in East Africa. From 2.6M to 1.7M years ago, Oldowan technology spread across the globe, with Homo erectus inheriting Oldowan technology and adapting it into the more advanced Acheulean type of stone tool manufacturing beginning about 1.7M years ago. Up until now, the evidence has seemed quite clear — tool use arises in East Africa and spreads out from there, moving along with hominin groups themselves. But a new discovery in Algeria, at Ain Boucherit, could upend our understanding of these timelines. New digs at that location have uncovered stone tools dating back to 1.92 – 2.4M years ago.
This suggests a pattern of hominin dispersal that’s considerably different than our previous models. This isn’t the first time old tools have been found outside Africa — there are stone tools in Georgia (the country, not the state) dated to 1.8M years ago, and sites in Pakistan and China dating to 1.8M and 1.66M years ago, respectively. But the question of when our ancestors spread to these locations is also tied to which of our ancestors spread to these locations, and that’s where things start to get rather interesting. Homo erectus, which arose 1.8M years ago, is known for having settled Africa, the Middle East, India, Pakistan, China, and the Indonesian islands. H. erectus is believed to have been the first hominin to have spread so widely out of Africa — earlier species of hominins are generally confined to various sections of Africa, radiating outwards from East Africa.
If there are hominins using tools in Africa 2.4M years ago, it means one of two things. Either the species of hominins living in East Africa at the time made a 2500-mile trip over difficult terrain with no particularly understood reason to do so, or there were unidentified groups of hominins living in North Africa at the same period of time who independently discovered Oldowan technology and began using tools. The earliest known hominin is 7 million years old and lived in Chad, illustrating that while East Africa may, in fact, have been the so-called cradle of humanity, various hominin species were spreading out across the continent millions of years before.
This potentially complicates the question of tool use. While tool use was once thought to be one of the most important differentiating factors between the genus Homo and Australopithecus, we’ve since discovered that some australopithecine species like Australopithecus garhi were likely tool users. Tool use has been observed in chimpanzee species as well. With no bones discovered at the Algerian site, we don’t yet know which of our ancestors, if any, had a hand in creating these ancient relics. What these finds show in aggregate is that our understanding of how hominins spread across Africa and the wider world remain incomplete.
Feature image courtesy of Wikipedia
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