Bone tools

Bone tools

Debate

The earliest modification and use of bone by hominins is a matter of considerable debate. The implications of this debate include the assessment of modern human behaviour and the criteria for identifying bone tools that are used and modified by hominins <ref name="d’Errico & Backwell ">d’Errico & Backwell 2005.

Hominin cognitive abilities The general consensus in the 1990s was that the African Middle Stone Age <MSA> hominins did not make bone tools. This interpretation regarding hominin behaviour was based on the assumption that MSA hominins did not have the cognitive abilities to produce complex bone tool technologies. Evidence for this view came from the rarity of bone tools in the African MSA deposits. Bone tools are commonly used to assess modern behaviour. Subsequently the relative abundance of bone tools and the occurrence of anatomical modern humans in the Later Stone Age <LSA> deposits, some 40,000 to 30,000 years ago, further supported the claim that MSA hominins did not have the mental capabilities to manufacture bone tools <ref name="Henshilwood et al">Henshilwood et al 2005. However, recent work in Africa and Europe has suggested that MSA hominins did have the mental ability to manufacture, use, and modify bone tools for various tasks. In addition, Neandertals are known to have manufactured bone tools during the Middle Palaeolithic, thereby refuting the assumption the bone tools are particular to anatomical modern humans of the LSA of Africa and the Upper Palaeolithic of Europe. In Africa, the first strong evidence for MSA bone tool production occurs in the form of barbed and unbarbed points from the Katanda sites in the DRC <Congo> which were dated to 75 Ka . Another large assemblage of MSA bone tools have also been recovered from Blombos Cave, South Africa. The 28 bone tools, including an MSA bone point, from Blombos Cave demonstrate that the MSA hominins had the cognitive ability to perceive bone as a raw material as well as the ability to utilize manufacturing techniques to produce various shaped bone tools for various function . The key issue of the debate regarding the earliest use of bone tools is whether modern human behaviour emerged with the appearance of anatomical modern humans as a behavioural 'package', or whether MSA hominins can be regarded as behaviourally modern in light of the new evidence of bone tools from MSA sites in Africa and Europe <ref name="Henshilwood & Sealy">Henshilwood & Sealy 1997.

Criteria for identifying hominin-made bone tools

Pseudo-tools Several taphonomic studies and mircowear analysis indicate that a number of natural processes can produce pseudo-tools <mimics of human-made objects> . 'Natural' modifications to bones, other than hominin-made, include gnawing or digestion by carnivores, rodents or herbivores; bone breakage for marrow extraction by carnivores; trampling; root etching; and weathering . In order to distinguish between pseudo-tools and true tools it is necessary to adopt an interdisciplinary approach combining taphonomic analysis; microscopic studies on traces of manufacture and use; and experimental replication of bone tools in order to draw comparisons for assessment of the purported bone tools .

South Africa

Swartkrans, Sterkfontein, Drimolen The earliest evidence for modification and use of bone points comes from the South African sites of Swartkrans, Sterkfontein, and Drimolen. These sites date to 1.8 and 1.0 Ma. Initially the bone tools were suggested to have been used for digging up tubers and working skins. <ref name="Brain & Shipman">Brain & Shipman 1993. Analysis on wear patterns have subsequently suggested that these tools were used to dig into termite mounds . Analysis of breakage patterns indicates that early hominins selected weathered bone fragments and horn cores for digging activities .

Taphonomic analysis of the Swartkrans assemblage indicates the use-wear is a diagnostic feature of bones tools <ref name="d’Errico & Backwell ">d’Errico & Backwell 2003. Metric analysis on the Swartkrans assemblage demonstrates that longer, wider and more robust bone fragments were selected by hominins for bone tool manufacture <d’Errico & Backwell’’/>. This further supports the taphonomic analysis in distinguishing bone tools and pseudo-tools <d’Errico & Backwell’’/>. Wear analysis evidence traces of grinding on used bone tools of the Swartkrans assemblage . Grinding, a technique particular to the bone tool, suggests that hominins utilized intentional shaping for the production of the bone tool . This suggests that hominins had the cognitive ability to modify a bone implement with the intention of enhancing optimal efficiency .

Who used the bone tools? The dominant hominin taxon found at Swartkrans and Drimolen is the robust australopithecines. In addition, these hominins were found in association with bone tools. This affinity with bone tools suggests that the robust australopithecines were the probable makers of the bone tools . In the absence of bone tools in sites younger than 1.0 Ma, a time when the robust australopithecines have disappeared from the fossil record, further suggests that ''Paranthropus robustus'' was responsible for the Lower Palaeolithic bone tools industry of southern Africa .

Blombos Cave <BBC>, South Africa The largest assemblage of bone tools occurs in the Middle Stone Age levels of Blombos Cave, South Africa. At this site 28 bone tools were recovered from the 77 Kyr MSA levels <ref name="Henshilwood et al">Henshilwood et al 2001b. Analysis of the assemblage indicate that the Middle Stone Age bone tool production followed a sequence of manufacture beginning with blank production, the use of various shaping techniques, and finally finishing the artifacts to produce awls or projectile points . The Blombos assemblage comprises mostly of awls modified by scraping as well as three points probably projectile points made for hafting . The manufacturing difference between awls and projectile points indicates that hominins utilized different methods of production of tools for different functions .

East Africa

''Olduvai Gorge'' Mary Leakey <1971> reported 125 modified bones and teeth from Olduvai Beds I and II. These bone tools were interpreted to have been modified by intentional flaking. According to Shipman <1998> the Olduvai bone tools collection can be described as consisting of anvils and tools for heavy duty activities such as butchering or digging . The purported bone tool assemblage consists of fresh bone shaft fragments and epiphyseal pieces from large and very large mammals and bearing five or more flake scars . Therefore Mary Leakey was correct in interpreting a collection of bones from Olduvai as bone tools used and modified by hominins .

Who were the tool makers? According to d’Errico & Backwell <2005> the bone tools only occur in Bed II thereby suggesting that the modification of bone fragments by flaking is not a feature of the Oldowan, but Developed Oldowan or Early Acheulean . This would have implications for who the tools makers were. In addition, the flaked bone tools appear in the same beds as ''Homo erectus'' <middle and upper Bed II> thereby suggesting that Homo erectus was atleast partly responsible for the Olduvai bone tools .

Europe

Used and modified bone points that function as awls or points have been found to occur at Lower and Middle Palaeolithic sites from Europe. Three Lower Palaeolithic sites in Italy, have yielded Acheulean-type bifaces made by flaking long bones of ''Elephas antiquus''. Other sites have yielded bone fragments used to retouch stone tools. Regardless of extensive studies done in order to distinguishing percussion marks and carnivore notches, the identification of bone tools shaped by flaking remains a matter of debate . Other sites such as Arcy-sur-Cure and Quincay in France date to between 40 and 35 Kya have yielded evidence of complex bone tool technology including personal ornaments, shaped and decorated awls, and many bone tubes.

Several perforated animal phalanges from Middle Palaeolithic sites have been interpreted as whistles or Neandertal bone flutes <ref name="McBurney">McBurney 1969. A Neandertal 'flute' from Divje Babe Cave in Slovenia found in Middle Palaeolithic layers of the cave <ref name="Turk et al">Turk et al 1995. It was described as the earliest evidence of a musical instrument, but it is a controversial musical instrument and has been found to be carnivore <bear> modified rather than hominin modified .

Who were the tool makers? Shaped bone tools were also reported several late Neandertal sites in Europe and were interpreted as resulting from an acculturation of the Neandertals by anatomical modern humans . Recent work has suggested the Neandertals did work bone. d’Errico et al <2003> have demonstrated that Neandertals were responsible for the ‘Chatelperronian’ bone awls and other bone tools, not their ''Homo sapiens'' successors. This provides further evidence that bone working as a modern behaviour was not exclusively associated with anatomical modern humans.