Shaped stone balls were used for bone marrow extraction at Lower Paleolithic Qesem Cave, Israel

Abstract

The presence of shaped stone balls at early Paleolithic sites has attracted scholarly attention since the pioneering work of the Leakeys in Olduvai, Tanzania. Despite the persistent presence of these items in the archaeological record over a period of two million years, their function is still debated. We present new results from Middle Pleistocene Qesem Cave on the use of these implements as percussion tools. Use-wear and abundant bone and fat residues found on ten shaped stone balls indicate crushing of fresh bones by thrusting percussion and provide direct evidence for the use of these items to access bone marrow of animal prey at this site. Two experiments conducted to investigate and verify functional aspects proved Qesem Cave shaped stone balls are efficient for bone processing and provide a comfortable grip and useful active areas for repeated use. Notably, the patina observed on the analyzed items precedes their use at the cave, indicating that they were collected by Qesem inhabitants, most probably from older Lower Paleolithic Acheulian sites. Thus, our results refer only to the final phases of the life of the items, and we cannot attest to their original function. As bone marrow played a central role in human nutrition in the Lower Paleolithic, and our experimental results show that the morphology and characteristics of shaped stone ball replicas are well-suited for the extraction of bone marrow, we suggest that these features might have been the reason for their collection and use at Qesem Cave. These results shed light on the function of shaped stone balls and are consistent with the significance of animal fat in the caloric intake of Middle Pleistocene humans as shown by the archeozoological evidence at Qesem Cave and possibly beyond.

Fig 1. Map of Qesem Cave site.

Red circles indicate the location of SSBs: Ten items found in the south west area; six items under the rock shelf; nine items in the southern areas; two items around the fireplace; two items found in non-excavated contexts).

Fig 2. Archaeological sample of SSBs found in Qesem Cave.

The archaeological samples discussed in the paper and characterized by use-wear and/or residues. For each specimen, three surfaces are presented (the white line indicates the side of the progressive rotation).

Fig 3. Half-ball from Qesem Cave.

Images of patinas with different colors and thicknesses, identified on the two surfaces of the tools. Surface 1: (gray) unmodified area with the neocortex; (green) knapped surface with the reddish and white patina; Surface 2: (blue) light-reddish patina covering the white patina on the knapped surface; (yellow) non-patinated surface on the knapped area; (pink) localization of the functional areas.

Fig 4. SSB from Qesem Cave (G21 715–720).

An example of patina removed by subsequent formation of use-wear. 1) Area with developed traces. Note long oriented striations (see black arrows) associated to negatives of micro-flakes (indicated by red arrows) observed at 50x; 2) Surface of the spheroid showing a granular patina covered by an orange and white patina (the black arrow indicates detachments that removed the patina) documented at 20x; 3) Detail of the patina removed by the use-wear. Note the cracks characterizing the orange and granular patinas observed at 40x.

Fig 5. Archaeological SSB (F17c 715–720).

Selection of macro-traces and residues preserved on one archaeological SSB from Qesem Cave. 1) Negatives of flakes localized on prominent ridges (10×); 2) Sheen surface (20×); 3) Detail of negative flakes (50×); 4 and 5) Micro-polishes localized on high ridges (50×–100×); and 6) Polish with smooth texture and domed topography (200×). The letters (a–f) indicate different types of residues identified on the archaeological tool: a–b) Spots of crushed amorphous white fatty residues and glossy film mixed with bone fiber; c–e) Crushed compact and spongy bone tissues; f) Spots of crushed greasy fat matter mixed with bone fragments.

Fig 6. Archaeological SSB (QC G21 715–720).

1–3) Macro-traces characterized by oriented striations and negatives of flakes; 4) Localization of micro-polishes on the high ridges; 5 and 6) Abrasions and micro-striations with different orientation suggesting a repetitive gesture with different directions. The micro-traces documented in this figure were analysed on the silicon cast (Provil Novo®).

Fig 7. Archaeological SSB.

QC H21 655–660:1) Macro-traces localised on high ridge; 2) Flake negatives; 3) Oriented striations (indicated by black arrows) with different directions and negatives of micro-flakes (indicated by the red arrows). Magnification 40x. QC I16c 570–580: 4–6) Cracks on the patinas due to the formation of new traces.

Fig 8. Experimental SSB replicas.

The replicas were knapped by J. Baena and employed in marrow extraction. a) Large size dolomite SSB; b) Medium-size limestone SSB; c) Medium-size flint SSB.

Fig 9. Marrow extraction experiment.

A large dolomite SSB used for bone breaking in order to extract the marrow (performed by J. Rosell).

Fig 10. Bone marrow extracted with an experimental SSB.

Fig 11. Experimental residues related to bone crushing.

(a) Collagen fibers and fragments of periosteum tissue localized on the top of the high ridges; (b,c) Amorphous reddish (meat- and blood-rich) animal matter compressed inside the negative scars; (d) close-up on amorphous whitish animal matter. Note the formation of an organic film with a glossy and striated appearance on top of the residue.

Fig 12. Experiments used for crushing bone.

1) Limestone spheroid with macro- and micro-wear: b) Medium-size spheroid in compact limestone related to the macro and micro traces.

Fig 13. Experiment used for crushing bone.

Flint spheroid and characteristic micro-traces localized on the high ridges associated with striations.

Fig 14. Comparison between experimental (left) and archaeological (right) use-wear.

Experimental traces (a,b,e,f,i,l): The black arrow indicated use-wear developed on the top of the high ridges (a); Small-flake detachment associated with oriented and striated residues characterized by a glossy-like appearance (b); Micro-polish localized on the high ridge (e) with smooth texture and domed topography (f); Patch of polish with micro-striations with the same orientation (i); Overlapping polishes with different orientation and rough aspect (l). Archaeological traces (c,d,g,h,m,n), localization of the use-wear on the high ridge (c); Oriented residues and striations (d); Micro-polish localized on the high ridge (g) with smooth texture and domed topography (h); Patch of polish with micro-striations with the same orientation (m); Overlapping polishes with different orientation and rough aspect (n).

Fig 15. Comparison between experimental (left) and archaeological (right) residues.

Experimental residues (a,c): close-up on amorphous whitish animal matter and the organic film with a glossy and striated appearance on top of the residue (a); White amorphous material composed of fat compressed and admixed with small particles of crushed bone (c). Archaeological residues (b,d): Compressed whitish amorphous material with organic glossy and striated film formed on top (b); Crushed bone compact tissue mixed to small amount of amorphous whitish residue with a compressed aspect (d).