Main

Evidence of the past presence of Neanderthals at archaeological sites is usually associated with subsistence activities, such as hunting, the processing and consumption of animal resources, the preparation of tools or the use of fire1,2,3,4,5,6. Less frequently, however, their presence can be associated with other functions, such as extractive activities (for example, flint quarrying7) and activities related to their symbolic world (for example, burials8,9,10,11 and the use of structures constructed for possible ceremonial use12). The present work examines an unusual archaeological assemblage, an accumulation of crania belonging to large mammals, apparently processed by Neanderthals, in Level 3 of the Cueva Des-Cubierta (in central Spain). Taxonomic and anatomical analyses of this assemblage, along with the taphonomic modifications to which its components were subjected, indicate that its origin lies in something other than practices associated with mere subsistence. Rather, it is probably associated with Neanderthal symbolism.

Results

Archaeological context

The Cueva Des-Cubierta (coordinates, 40°55′23″N 3°48′29″W, WGS84 datum; altitude, 1,112 m) forms part of a multi-level karstic system consisting of subhorizontal conduits in outcrops of Cretaceous marine carbonate running along the right bank of the upper River Lozoya Valley, in the north of the Madrid Region (Spain). It was discovered in 2009 during survey work performed within the framework of the archaeological activity undertaken in the area since 200213,14,15. The cave, which runs zigzag for some 80 m and is 2–4 m wide, has lost its ceiling due to the erosive dismantling of its dolomite (Supplementary Results, ‘The site’).

In the main gallery, an immature human mandible and six deciduous teeth have been recovered from Level 2 (ref. 16) (see also Supplementary Results, ‘Human remains’). The developmental stage of these teeth and the developing permanent tooth germ within the body of the mandible suggest (by modern standards) that these items belonged to a single individual who died at the age of 3–5 years17 (see also Supplementary Results, ‘Human remains’). The lack of a bony chin, the degree of shovelling and the crown outline of the molars are typically Neanderthal18,19 (see also Supplementary Results, ‘Human remains’). In addition, the lithic industry represented in Level 2 (n = 734 elements), made mainly of quartz, is clearly Mousterian. Despite the peculiarities of quartz knapping, the use of discoid knapping for flake extraction, the presence of denticulates and notches among the retouched elements, and the absence of any large cutting tools or laminar elements confirm the Mousterian character of these elements (Extended Data Fig. 1 and Supplementary Results, ‘Lithics’).

The underlying Level 3 contains an accumulation of clast-supported subangular dolomite blocks and carbonate boulders in a sand–clay matrix. Covering some 27 m2 and reaching 2 m in depth, it houses the archaeological remains discussed in this work. Its biochronological context and available dating evidence place this level within MIS4 or the first half of MIS3 (Supplementary Results, ‘Faunal remains’, ‘Radiocarbon dating’ and ‘U/Th datings’). The pollen record suggests the climate to have been drier and colder than at present (Supplementary Results, ‘Palynology’). Plant diversity was limited, woodland development was patchy, and Juniperus and other steppe plants were in expansion at this time. These environmental conditions agree with those suggested by a study of the level’s association of micromammals, which is dominated by different species of vole (Microtus arvalis, M. gr. agrestis and M. gr. lusitanicus-duodecimcostatus) plus some remains of Ochotona cf. pusilla, all indicators of an open landscape with little forest (Supplementary Results, ‘Faunal remains’). The presence of type T-55 and 7A spores, which are associated with fire, agrees with the recognition of combustion areas in Level 3 (Supplementary Results, ‘Palynology’).

Level 3 also contains ample evidence of lithic industry. In total, 1,421 anvils, hammerstones, cores, flakes and shaped tools have been recovered, all belonging to the Neanderthal Mousterian technocomplex (Extended Data Figs. 1 and 2 and Supplementary Results, ‘Lithics’). The most common raw materials are those available locally. Quartz stands out for its abundance, and gneiss for the size of the pieces made from it, particularly hammerstones and anvils. Broken hammerstones were frequently reused as cores. The most used knapping methods were expeditive, followed by centripetal and orthogonal methods used in both bifacial and unifacial manners. Among the shaped tools present, denticulates and notches are the most common, followed by sidescrapers and retouched flakes. The presence of debris and refittings confirm that some lithic tools were configured inside the cave during the formation of Level 3.

Signs of thermoalteration were noted on elements of lithic industry (1.1% of the lithic remains recovered), on dolomite clasts (13.0% of all such clasts documented) and occasionally on the remains of micromammals (Supplementary Results, ‘Evidences of fire’). Charcoals (n = 338) were also present in the assemblage. Overall, 34.0% of the archaeological record of Level 3 was affected by fire. Although it was hard to find conserved combustion-associated structures in the sedimentary matrix20, the documentation and spatial analysis of the thermoaltered remains allowed the identification of concentrations of fire-affected materials and specific points of combustion, including an area in the cave that conserved a directly burned speleothemic floor (the top of speleothem S1 in contact with Level 3) (Extended Data Fig. 3 and Supplementary Figs. 3139). This shows that fires were made inside the cave.

The large mammal assemblage

A total of 2,265 faunal remains over 2 cm in length have been recovered from Level 3, of which 1,616 have been identified taxonomically (Supplementary Results, ‘Faunal remains’). Ungulate remains dominate over those of carnivores (the carnivore-to-ungulate number of identified specimens (NISP) ratio is 1.6%21). The best represented of these ungulates are bovines (Bison priscus and Bos primigenius), followed at some distance by cervids (Cervus elaphus and Capreolus capreolus), steppe rhinoceroses (Stephanorhinus hemitoechus) and horses (Equus ferus) (Table 1). Analysis of the bone modification surfaces revealed these remains to show very few signs of predator activity (0.2% show furrowing); those that were detected were always found on post-cranial elements of the skeleton. The scarcity and poor definition of these modifications made it impossible to identify the predator involved (Supplementary Results, ‘Taphonomy’).

Table 1 Quantification of the abundance of large mammal species in Level 3

Some of the bone remains showed signs of thermoalteration (30.5%). Bones measuring 2–5 cm were the most affected, and carbonization was the most documented type of impact. Cranial and post-cranial remains were affected to much the same extent (around 20%) (Supplementary Results, ‘Evidences of fire’).

Overall, anthropic modification of the faunal remains was scarce (1.6%) and concentrated on post-cranial elements, especially the bones of the appendicular area (Supplementary Results, ‘Taphonomy’). The most common modification was fracturing (1.4%) by direct percussion to extract the bone marrow. Cut marks were found on just 0.3% of the studied bones. Four remains showed both types of modification. However, two crania, one belonging to S. hemitoechus and one to B. priscus, showed clear anthropic cut marks (Extended Data Figs. 4 and 5). Although post-depositional fragmentation made it difficult to study the evidence of anthropic fracturing, the former cranium showed signs of this as well as the noted cut marks. Indeed, some crania were spatially associated with anvils and hammers (Figs. 1 and 2).

Fig. 1: Gneiss anvil under an aurochs cranium.
figure 1

Detail of the excavation of Level 3 in square H′44, in which an aurochs (Bos primigenius) cranium (18/29/CDC/H′44/101/272) was identified. The black arrow points north. Under the cranium (above the scale bar), a tabular gneiss boulder was found. This is an allochthonous element for Level 3, which is composed of angular to subangular cobbles and boulders of limestone and dolostone, and a scanty carbonatic, silty matrix. It must have been brought into the cave by Neanderthals. Its poor preservation (its surface is altered, causing the disaggregation and loss of its mineral grains) allows no evidence of its use to be gleaned (see Supplementary Fig. 24 for a diagram highlighting the important elements in the picture).

Fig. 2: Steppe rhino cranium associated with a hammerstone.
figure 2

Detail of the process of excavation of Level 3 in square J′40, where a Stephanorhinus hemitoechus cranium (16/12/CDC/J′40/101.2/691) was found (face down). The photographed surface is approximately horizontal. The black arrow points north. The cranium lacks maxillae. Just above the cranium, there is a rounded granite boulder (16/12/CDC/J′40/101.2/600) with a battered area, indicating its use as a hammerstone. Note the bison horn core just above the rhino cranium and the remains of a large bovid cranium to the right (see Supplementary Fig. 25 for a diagram highlighting the important elements in the picture).

The most notable feature of this large mammal association, however, is its anatomical composition (Extended Data Fig. 6 and Supplementary Fig. 15), which is clearly dominated by cranial remains, mostly crania with missing maxillae. Teeth are very scarce. All these crania belong to species with some form of appendage (bony horn cores, antlers or keratinous horns). Equus ferus, the only species with no cranial appendage belonging to the assemblage, is currently represented by only a tooth fragment and a metapodial. In total, the remains of 35 crania have been recovered, of which 28 belong to bovines (B. priscus, 14; B. primigenius, 3; Bos/Bison, 11), 5 to cervids (C. elaphus, 5; all males bearing their unshed antlers) and 2 to rhinoceroses (S. hemitoechus) (Extended Data Figs. 7 and 8). Many have suffered intense post-depositional fragmentation caused by the sediment that surrounded them. However, detailed analysis of the recovered fragments indicates that many of the crania (39.3%) initially conserved the frontal region, including any horn cores or antlers, as well as the occipital and nasal areas, but not the maxillae, the bony palate or the zygomatic bones (Figs. 3 and 4). Some crania were found lying over clusters of thermoaltered materials, including burned cranial fragments.

Fig. 3: Steppe bison cranium from Level 3.
figure 3

This is one of the best-preserved Bison priscus crania from Level 3 (11/13/CDC/G′42/1/14). It shows the typical features of the set of the bison crania recovered at this level: the absence of zygomatic bones and maxillae, the preservation of the nasal and frontal bones, and horn cores. The nasal bone shows cut marks (Extended Data Fig. 4). Photo credit: Javier Trueba/MSF.

Fig. 4: Steppe rhinoceros cranium from Level 3.
figure 4

Two Stephanorhinus hemitoechus crania were found in Level 3, both of similar integrity. Both lack maxillae (although the right maxilla of the cranium shown (15/13/CDC/H′42/101/50) was found underneath it). Numerous cut marks were identified on the zygomatic and basisphenoid bones of the pictured specimen, as well as evidence of anthropic fracturing (Extended Data Fig. 5). Photo credit: Mario Torquemada/MAPCM.

Experimental butchering

The identification of anthropic marks on the crania and the under-representation of zygomatic bones, maxillae, mandibles and teeth suggest that the heads of these animals were first processed outside the cave. The scarcity of these elements has been interpreted in light of the results obtained in the experimental butchering of cow heads. Three cow heads were butchered, each by an experienced butcher, to identify which bones needed to be discarded or broken to extract the meat, brain and marrow of the heads (Supplementary Results, ‘Taphonomy’). When these cranial parts were removed through direct percussion, it was easy to extract the eyes (which are nutritive), but if these bones were not broken, the removal of these organs was extremely difficult. In addition, during the breakage of the maxillae, some upper teeth were accidentally extracted. If the first round of the butchering process had been performed inside the cave, fragments of mandibles, maxillae, zygomatic bones and/or upper and lower teeth would have been found. However, as indicated above, these elements are very scarce in Level 3. Thus, the initial butchering must have taken place outside the cave and was probably related to the consumption of the meat on the head, the tongue and eyes.

A second round of processing took place within the cave, perhaps related to accessing the brain and/or working the crania into the configuration in which they were found in Level 3. Although it is difficult to speak of a clear configuration for these crania, it is evident that a final round of their modification occurred in the cave. This is supported by the large number of percussion-associated tools present (~14% of all the lithic tools), by the percussion marks associated with the removal of the maxillae and the extraction of the brain (at least in the case of a rhinoceros cranium) (Extended Data Fig. 5), and by the presence of some isolated cranial fragments.

During the experimental butchering (Supplementary Results, ‘Taphonomy’), different options for accessing the brain were tested. The easiest method was to break the occipital bones. At the site, these bones are generally not complete and are sometimes isolated, suggesting that the Neanderthal occupants probably worked on the crania inside the cave to extract the brain.

Discussion

The anatomical, taxonomic and taphonomic features of this association do not match what would be expected for a water- or gravity-driven accumulation22,23, a natural trap24 or a carnivore den25,26,27. Nor are they consistent with those resulting from the practice of subsistence activities by Neanderthals, such as hunting or the processing and consumption of their prey5,24,28,29. Although the high relative frequency of minimal animal units (%MAU) of crania might suggest the existence of a carnivore den, the anatomical and taxonomical features of the bone assemblage are not similar to those produced by carnivores, and certainly not by hyaenas25,26,27. Given the number of crania, another interpretation of the site might be that Level 3 was a kill-site. However, this can be ruled out given the absence of low-nutritional elements typically found at kill/butchering sites, such as flat bones30,31,32. Neither are there any parallels with the contexts interpreted for other, nearby sites in Pinilla del Valle. Certainly, for Level F of the Navalmaíllo Rock-shelter, where a Neanderthal hunting camp has been detected5, the skeletal profile matches those identified for other anthropogenic faunal accumulations of the Middle Palaeolithic. Other sites at Pinilla del Valle have been identified as hyaena dens (for example, at the Camino cave and Buena Pinta cave), for which the skeletal profiles are typical33,34. The faunal assemblage of the Cueva Des-Cubierta, however, is quite different and is not found elsewhere in the local archaeological record.

Studies involving modern hunter-gatherer groups have shown that the heads of large animals are usually discarded and not taken back to camp, since they are heavy and of lower use as food35,36,37,38,39,40. The introduction of the crania, and not of other parts of the carcasses of greater nutritional interest, into the Cueva Des-Cubierta thus seems to have been deliberate and not related to subsistence. Rather, it seems more related to their symbolic use.

To date, no site exclusively related to symbolic activity has been identified in the Neanderthal archaeological record. This is a limitation when trying to interpret the type of activity that the Neanderthals involved might have undertaken there: there is simply no comparative framework to help in this regard. Parallels with ethnographic examples might be useful in addressing this question.

Today, the accumulation and display of large mammal skulls in the form of hunting trophies is linked to sport hunting. Similar practices for varying purposes have, however, also been documented for the most recent hunter-gatherer societies41. Indeed, cultures worldwide have invested animal skulls with a strong symbolic content and have protected or displayed them with due attention42. The skulls of hunted animals were stored as souvenirs or hunting trophies among the Achuar people of South America43 and the Wola of New Guinea44. In other cultures, skulls (or other bones with symbolic meaning) were grouped together to form caches associated with hunting rituals. Different authors have understood these caches to be hunting shrines41,45,46. The display or accumulation of trophy skulls has also been linked to the construction of masculine identity (for example, among New Guinea lowland groups47) or the performance of specific ceremonies (for example, in the Ainu culture of northern Japan48). Other skull accumulations have been related to burial rituals (for example, among the Uilta people of Shakalin Island49).

In the present case, the fact that the crania all belong to species with cranial appendages (unshed antlers in the case of the deer) suggests that they may represent trophies. Their concentration in a small space also suggests that the accumulation might be considered a hunting shrine. However, other interpretations cannot be ruled out, such as a link with ritual and fire (given the proximity of the evidence of the latter’s use), some expression of the symbolic relationship between Neanderthals and the natural world, or some kind of initiatory rite or propitiatory magic.

The characteristics of the Cueva Des-Cubierta archaeological assemblage remain the same over the ~2 m thickness of Level 3 (Extended Data Fig. 9). The finding of crania, thermoaltered materials and lithic elements throughout, along with the continued presence of the tools necessary for that exploitation over the entirety of Level 3 (sometimes superimposed but separated from one another by packages of sediment), indicates that the site’s Neanderthal occupants repeated the same type of behaviour over a long period (years, decades, centuries or even millennia). The intentional deposition of large mammal crania over the time that Level 3 formed suggests the transmission of this behaviour between generations, which would be consistent with its interpretation as a cultural phenomenon.

Very few other accumulations of crania in Mousterian contexts are known. De Villeneuve50 described a Neanderthal accumulation of crania belonging to Capra ibex, Bos primigenius and Cervus elaphus in Level Foyer B of the Grotte du Prince (France), which was interpreted as a collection of hunting trophies. However, the absence of modern taphonomic studies on this assemblage requires that caution be used before this interpretation is fully accepted. Neanderthal burial sites have also been associated with deposits of large animal crania. Bonifay and Vandermeersch51 refer to a cranium and other bones of a cave bear in Le Regourdou Cave (France) as possibly reflecting a Neanderthal funerary offering, although this has been questioned by some authors52,53,54,55. Other possible offerings of crania at Neanderthal burial sites have also been reported (for example, in Teshik-Tash in Uzbekistan56). It is not until the arrival of anatomically modern humans, however, that the probable use of crania in ritual or symbolic contexts becomes more evident. For example, modern humans have been associated with the steppe bison cranium (interpreted as a possible hunting trophy with symbolic meaning57) found at the Régismont-le-Haut (France) site, with the cave bear cranium placed on a rock in the Grotte de Chauvet (France)58,59 and with the ochred steppe bison crania and jaws found at Anesovka II60. Large mammal crania have also appeared associated with modern human graves and have been interpreted as offerings—for example, the rhinoceros cranium at Brno 2 (Czech Republic)61 or the mammoth cranium associated with the ‘Red Lady’ grave in Paviland (Wales)62 (both in a Gravettian context). The accumulation of crania in the Cueva Des-Cubierta reported here provides further evidence of Neanderthal symbolism associated with the animals these humans hunted.

Methods

Permission to conduct the excavations was granted by the Dirección General de Patrimonio Cultural of the Comunidad de Madrid.

Field methods

When the excavation of the site began in 2009, a grid of 1 m2 squares was established. Each square was identified by a letter and a number. The letters grow towards the east, and the numbers grow towards the north.

The excavations were concentrated in the sector of the cave called La Monumental. The filling of the cave is well marked in terms of width by the walls of the cave. Given the need to know the cave’s complete stratigraphy, a trench with an approximate east–west direction began to be excavated in this sector in 2015. This trench occupies line 42 in the plan of the site (Extended Data Fig. 7). Excavations are still underway; the base of the fill has not yet been reached.

Excavation was carried out by archaeological level and, within each level, by artificial intervals (10 cm thick). The locations of the archaeological and palaeontological material and blocks of extracted rock were recorded with respect to an absolute coordinate system (datum ED50) using a motorized Leica total station (model TCRP 1205 R400). All data were exported to Excel 17.0 and then to a FileMaker Pro 7.0v3 database.

Stratigraphic levels were described, measured, logged using scaled drawings and photographed. Level limits were measured and recorded using a total station. Representative samples of each level from freshly scraped exposures were collected for granulometric analysis. Sieves (−1 to 4 φ) were used for measuring grain size distribution; sediment types were classified on the basis of this distribution63.

All the lithic industry detected was collected and drawn, regardless of size, as well as bone fragments over 2 cm (on the longest axis). All blocks of carbonatic rocks larger than 20 cm were also documented. All field drawings were made at a scale of 1:10 and digitized using a Wacom Intuos 4 professional pen tablet.

The coordinates of archaeological items were analysed spatially using AutoCAD 2021 and QGIS v.3.22. Different plans and sections were made from the spatial data to facilitate its visualization. These products were used to determine whether the distribution of the archaeological materials was homogeneous over the site’s extension or whether they appeared concentrated in specific sectors. The transversal and longitudinal sections allowed the vertical succession of the materials to be visualized and, taking into account the data derived from the geological and taphonomic studies, allowed temporal relationships between them to be established. The recovered objects were represented by their coordinates on the x, y and z axes in all plans and sections. The outlines of the large mammal crania were drawn in these plans and sections using information from photographs, field drawings and the spatial data.

Each recovered element was stored separately in a sealed plastic bag with its corresponding label containing information on the level, sublevel, square, order of recovery in that square, type of material, z coordinate (depth) and date. Larger fossils, also labelled, were stored in a container suitable for their characteristics. Only unidentifiable bones smaller than 2 cm from within the same square were kept together in a ‘level bag’; their coordinates were not recorded.

All excavated sediment was stored in bags labelled according to its origin (square stratigraphic level and depth range) for later pressurized water washing over a set of superimposed sieves.

Human remains

The available mandible and isolated deciduous teeth were μCT-scanned to provide a virtual reconstruction of the mandible and to assess the developmental stages of the permanent dentition inside the mandibular corpus. All scanning was performed at the maximum resolution obtainable using a Phoenix v|tome|x s scanner (GE Measurement & Control) at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Burgos, Spain. The isolated teeth were aligned along their long axis, with the crown placed upwards. Slices were then obtained in a 527 × 734 matrix in Dicom format, with an isometric voxel size of 0.019 mm (scanner energy, 110 kV; field of view, 0.9 cm). For the mandible, slices were obtained in a 1,880 × 1,176 matrix in Dicom format, with an isometric voxel size of 0.025 mm (scanner energy, 110 kV; field of view, 4.6 cm).

Virtual reconstruction was performed using Mimics v.18 software (Materialise), relying on semiautomatic segmentation to define Hounsfield values for dentine, enamel, bone and air. The virtual reconstruction of the mandible was performed taking into account the sagittal plane (symphysis) and mirror-imaging the preserved portions.

Faunal remains

Reference collections and bibliographic sources were used for the identification of microvertebrate remains (rodents64, lagomorphs65, insectivores66,67, chiropterans68,69,70,71, amphibians72,73,74,75,76 and reptiles77,78,79). The systematics used in this work are those previously proposed for rodents80,81, insectivores82, chiropterans83, lagomorphs80, and amphibians and reptiles84,85.

Atlases of animal anatomy86,87,88,89 and additional comparative data from bibliographic sources22,90,91,92,93,94,95 were used for the anatomical and taxonomic identification of large mammal remains. For bovine remains, identification also involved the use of the criteria of the Natural History Museum of Rotterdam (the Netherlands) and the Department of Geology, University of Oviedo (Spain), as well as skulls of current Bison bonasus provided by the Palaeolithic Vivo Park (Salgüero de Juarros, Burgos, Spain). For the rhinoceros remains, other sources were consulted96,97. In-house data for modern Panthera leo collections and Panthera spelaea specimens (from the Museum of Vertebrate Zoology—UC Berkeley, the Smithsonian Institution, the British Museum, the Sociedad Aranzadi and the Institue für Quartarpalaontolgie Weimar) were used in comparative analyses.

Measurements were taken using a Mitutoyo digital caliper, recording to the nearest 0.05 mm. The osteological and dental terminology used, and the measurements made of teeth and bones, were those previously proposed98.

The data collected for each bone remain were anatomical element, taxon, size, position, age, portion and side99. Six measurements of abundance were recorded: the number of specimens (that is, the total number of faunal remains independent of their level of identification)100, the NISP, the MNE, the MAU, the standardized %MAU and the MNI101,102.

Non-identified specimens were included in three bone categories: long bones, flat bones and articular bones. Bones that showed structural features of ribs and vertebrae were classified as indeterminate flat bone/vertebra/rib. The non-identified specimens were classified into three size categories depending on the modified criteria of Rodríguez-Hidalgo103, who in turn modified the categories proposed by Brain104 and Bunn105 in their studies on extant African fauna and those of Díez Fernández Lomana106 (Supplementary Table 5).

To express the relative abundance between carnivores and ungulates (C/U ratio), the following ratio proposed by Thackeray21 was used:

$${{{\mathrm{C/U}}}}\;{{{\mathrm{ratio = }}}}\left( {{{{\mathrm{MNI}}}}\;{{{\mathrm{of}}}}\;{{{\mathrm{carnivores/ MNI}}}}\;{{{\mathrm{of}}}}\;{{{\mathrm{ungulates}}}}} \right) \times 100$$

In the present work, NISP values were used instead of the MNI values to calculate this index.

Palynology

For the extraction of pollen grains from each of the studied samples, the sediments were chemically attacked using acids and alkalis according to standard protocols107. The residue was then subjected to enrichment by flotation in a heavy liquid of density ≥2. The residues were mounted on slides and examined under a light microscope. For each slide, pollen grains were counted along 42 rows covering the entire surface of the slide. Some of the samples from Levels 5 and 3 contained <100 grains; a pollen presence histogram was used to represent the results. Taxa were recorded as arboreal, shrubby and herbaceous types. The statistical treatment of the data, as well as their graphical representation, was undertaken using TILIA software108,109.

Evidence of thermal alteration and hearths

A collection of different archaeological materials from the cave was examined macroscopically to search their surfaces for any signs of alteration by fire and to characterize these signs. A spatial distribution analysis of the studied materials was then performed using AutoCAD and QGIS software. The location and arrangement of remains affected by fire within the deposit facilitate and complement the identification of areas where combustion occurred110,111.

The dolomite clasts forming part of the sediment matrix of Levels 2 and 3 sometimes showed signs of having been affected thermally. These were identified and classified as previously reported112 for carbonated sedimentary rocks, taking into account changes in coloration, cracks and alterations caused by high temperatures.

Some lithic industry artefacts and remains showed signs of exposure to heat and fire, as determined by the presence of potlidding, cracking and flaking, loss of shininess (for quartz), colour changes, thermal lustre, and fractures (in flint). Several studies have reported common alterations to different raw materials caused by fire, including quartz113, while others have recorded the differences between naturally and intentionally heat-treated flint114,115,116.

Some of the bone remains also showed signs of thermal alteration. The main feature of burned bones is the change in colour related to the intensity of the fire and the time of exposure. The burned bones from this assemblage were clustered into five colour groups117,118: Grade 1, brown points dispersed across the bone surface; Grade 2, brown stains more or less homogeneous across the bone surface; Grade 3, black stains where the bone was charred; Grade 4, grey and white stains, although occasionally with bluish veins; and Grade 5, calcined and completely white.

Charcoal fragments were identified taking into account the specialized literature on their recognition via the internal structure of the fragments and the taphonomic processes undergone119,120.

Taphonomy

The surfaces of all remains recovered were examined macroscopically and microscopically using an Olympus SZ1144TR (×15–×40) binocular microscope and a DigiMicro 2.0 Scale (×20–×200).

Cut marks were identified on the basis of previously proposed criteria121,122,123,124. The distribution, incidence and morphology of cut marks allows for the identification of different butchering activities121. Percussion pits, conchoidal scars, flakes and peeling caused by the anthropic breakage of the bones were also sought125,126,127. The presence of damage and its location were recorded for each of the remains analysed.

Carnivore modifications (tooth marks) were sought in the form of pits, scores and perforations121,128. The length and the width of these tooth marks and their location were recorded129,130,131,132. The presence of pitting and furrowing was also noted121,133.

Post-depositional modifications were noted in terms of presence/absence. Most of these modifications (black manganese oxide stains, dissolution, rounding and polishing by water abrasion, and concretions) are associated with the karstic depositional environment in which the materials were found134,135,136.

All faunal remains were subjected to classic taphonomic analysis. In addition, experimental butchering was performed to compare the results of the breakages made with the collected morphotypes. Three cow (Bos taurus) heads were butchered (one each by three experienced butchers) following different strategies to extract the brain. The butchers tried to identify the easiest way to extract the edible resources (eyes, brain and meat), always from a qualitative point of view (no quantitative data were collectable). In all cases, the butchers used stone tools (simple flakes) made from the raw materials (quartz, quartzite and porphyry) present in the lithic record for the site. All the raw materials were collected in the surroundings of Pinilla del Valle.

All experimental processes were undertaken at the Valle de los Neandertales Archaeological Park enclosure under natural conditions to reduce any possible bias produced by laboratory conditions (under which butchering is ergonomically easier).

The first stage involved the skinning of the heads. Most of the muscles (for example, the tongue) were then removed and the mandibles extracted (in agreement with the absence of these elements in the site) using gneiss, quartz and porphyry hammerstones. These raw materials were selected for use as percussion tools since most of the hammers found at the Pinilla del Valle sites (including the Cueva Des-Cubierta) are made from these kinds of rock. When the crania and mandibles were completely separated, the maxillae were removed. The zygomatic arches were then removed using hammerstones to extract the eyes.

Finally, the brain was extracted by (1) breaking the ventral part of the cranium, hitting it near the basilar part of the occipital bone; the brain was then extracted from within this area; (2) hitting the squamous part of the occipital bone (on both sides of the sagittal crest) with a hammerstone and then extracting the brain from within this area; or (3) hitting the frontal bone with a hammerstone and then extracting the brain from within this area. These three options were followed to check whether any provided an easier way to extract this organ.

Radiocarbon dating

Several samples (charcoal and charred bones) from Levels 2 and 3 were sent to the Oxford Radiocarbon Accelerator Unit for radiocarbon dating by accelerator mass spectrometry using the ultrafiltration method. The chemical pre-treatment, target preparation and accelerator mass spectrometry measurement were as previously described137,138. Only one of the samples (OxA-31346, a charcoal fragment from Level 2) could be dated. The result was calibrated using OxCal v.4.4 software139 and the IntCal20 calibration curve140. The calibrated age was expressed in anni cal BP (95.4% confidence or 2σ). The dating results are available in the Supplementary Results under ‘Radiocarbon dating’.

Uranium/thorium dating

The underlying speleothems S1 and S2 were sampled (using a hammer and chisel) for dating by the U/Th method to provide an estimate of the maximum age of Level 3. The S1 sample was divided into two. One part was sent to the Uranium Series Laboratory of the CENIEH, and the other to the Geochronology Laboratory of the Jaume Almera Institute of Earth Sciences (CSIC). S2 was dated at the CENIEH Uranium Series Laboratory.

The methodology and dating protocols used at the first of these laboratories have been previously described141. This facility works with small samples (around 50 mg); different subsamples taken from across the thickness of the speleothem could therefore be dated. The individualized datings obtained cover the interval of formation of the speleothem. The methodology and dating protocols used at the second laboratory are described elsewhere142. This laboratory works with bulk samples and therefore analysed the speleothem as a whole, obtaining an average age for the time interval during which it formed.

Reporting summary

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