Occupation strategies within the second half of the Middle Pleistocene and beginnings of the Upper Pleistocene stand out due to the elevated mobility of human groups. This type of mobility is understood as itinerary or migratory repeated movements related to the exploitation of the natural resources of the territory. This pattern, therefore, would limit the duration of the occupations in the different habitat places documented in the archaeological sites.
Although we have located some occupations in the open air, karst habitats are preferential spots for human groups of these chronologies. Caves or shelters have important advantages, giving protection from adverse climatic circumstances. The morphological characteristics of the cavities and their proximity to the main economical resources are essential in the election of the location.
Sedimentary formation processes of sites in cave can be highly complex. These processes normally present slow burying rates or periods of sedimentary stasis, giving place to the formation of palimpsests (various assemblages of fossils which come from different human occupations with a uniformed appearance in a same archaeological unit) which prevent the distinction or the isolation of each one of the occupations.
Nevertheless, there are mechanisms which help to make an individualized approximation of these occupations, as is the archaeo-stratigraphic (vertical) distribution of the 3D-located remains or the appliance of a refitting system.
Human occupations in an archaeological site can be identified with an archaeo-stratigraphic analysis, which is a study of the temporal and stratigraphic resolution of the archaeological material’s units in the sedimentological levels of the site. This analysis relates the archaeological materials to their sequential location looking for the major concentration of these in packets, in comparison to the absence of the same in sterile layers. For this, we reconstruct by means of an informatic software the original location of each one of the archaeological remains recovered, analyzing the group with sections which allow us to identify unoccupied human phases of the cavity and so delimit the ones which do have occupations.
The archaeostratigraphic study, taken place in the western sector of Bolomor Cave, between levels I and XII of the sequence, has allowed us to identify at least nine phases of clear unoccupied moments, which delimit ten levels of occupation, with a chronology between 100.000 and 180.000 years before present. These occupation levels show the repeated use of the cavity. The individualization or separation of these occupational levels is the main aim of the archaeo-stratigraphic analysis, as a parting point for other studies which allow us to reconstruct as a whole the characteristics of the human occupation.
The unoccupied phases identified in levels I to XII coincide principally with the sedimentological changes observed in the stratigraphic sequence, except in levels I, IV and XII, which also present an unoccupied moment inside the same level without this geological change.
From these archaeo-stratigraphic studies and their relationship with other disciplines, as is the analysis of lithic industry and of faunal remains from each unity, we have observed significant differences in the occupational pattern of the human groups which lived in Bolomor Cave all along its stratigraphic sequence.
Human occupations 120.000 years ago, level IV
Occupations of the upper part of the Bolomor sequence in general, and of level IV in particular, are characterized by having an elevated density of archaeological remains. This level, for example, has 6442 archaeological remains by m3. The sedimentation rate is very high, which indicates that the level was formed during a relatively short period of time, from the geological point of view. This fact has been contrasted with sedimentology, with the taphonomic analysis of the fauna, in which there is scarce presence of weathering (bone alterations generated by the exposition to atmospheric agents), and with the spatial studies of level IV.
The archaeo-stratigraphic analysis of level IV indicates the existence of two well defined occupational phases (CBIV-1 y CBIV-2). On the second of which we have identified four combustion structures which articulate the space and the development of associated activities. Occupation phases, although they show a high temporal relation, are due to the recurrent use of the cavity by human groups, with various occupations with some temporal continuity and a high recurrence in the use of spaces.
All along the formation of level IV we haven’t identified elements which indicate long unoccupied periods. The scarce incidence of carnivores and the archaeo-stratigraphic distribution of the remains intervened by them corroborates this phenomenon. We have to bear in mind that the presence of carnivores is incompatible with that of human groups and, therefore, modifications generated by them indicate periods without human occupations. The vertical distribution of the modified remains by these predators in level IV don’t show lineal assemblages which allow us to talk of relatively long periods of no human occupation at all. We haven’t recovered either elements which characterize the presence of dens or shelters. The altered remains are distributed in a disperse way all along the sedimentary packet. In this sense, it is possible to deduce intermittent periods of human occupation, alternated with brief intrusions of carnivores.
Both zooarchaeological and lithic industry studies evidence the durable and reiterated character of the human occupations of level IV. Bone remains recovered in this level indicate the existence of a wide spectrum of species, a total of 30 with very different ethological characteristics. This could indicate a human permanence in the shelter, which would suppose a major dominion of the environment and would allow the widening of the spectrum of potential preys. This specific diversity can also be related with a development of strategies in order to obtain resources, be with hunting techniques or capture systems of small preys. Also, we observe an elevated systemization in the anthropic processing of the animals, both on external and internal resources, probably related to durable occupations in which the group would share their manner of acting over such resources.
On the other side, the systematic incorporation of small preys to the diet has been related by diverse authors with a reduction of a territorial mobility. In this sense, the abundance and diversity of small preys in level IV is higher than the one identified in other levels of the site. In base to this, it isn’t strange to think that the widening of the diet in this level can respond to a major occupational stability.
Lithic industry stands out on a selection of prime material of better quality, principally flint, and a reduction of the secondary prime materials as limestone and quartzite, which can prove a more durable occupation and a less impact on expeditious activities related to sporadic visits to the cavity. Industry stands out with an intense reuse and recycling, giving place to a very small industry, due to its continuous reviving and transformation. This process is also related to an elevated occupational intensity, which takes us to the maximum exploitation of the prime materials transported to the site and even to the reuse of the existent in the same site, belonging to previous occupations.
The spatial analysis of level IV took place in an individualized way over units CBIV-1 and CBIV-2, identified from the archaeo-stratigraphic analysis. This study indicates the existence in both units, of a complex spatial structure, as reflect of the spatial and social organization of the campsite. In these occupations we observe a marked difference between the external area and the interior of the shelter, with human groups choosing the protected zone for their campsite and discarding the external zone, which is used for very expeditious activities. In occupation CBIV-2 hearths are situated coinciding with the line of the shelter’s visor, leaving the occupied area underneath its protection, delimited by hearths.
In both units we’ve identified other activity areas in which have taken place different domestic activities, as are the processing and consuming of animals or the elaboration of tools. These activity areas are not only related to a specific process, but they are used for other type of actions associated to the occupation. In unity CBIV-2, the activity area is associated to the hearths, next to which we find processed animals for their consumption, fracturing the long bones in order to obtain the marrow, and configuring lithic industry in order to be able to do so. We have registered archaeological evidence of anthropogenic processing as are cut marks related with different stages of the operative chain (skinning, viscera removal, dismembering, defleshing, disarticulation and periosteum removal) over carnivores such as foxes (Vulpes vulpes) or lions (Panthera leo), ungulates with different sizes as are red deer (Cervus elaphus), tars (Hemitragus cedrensis), horses (Equus ferus, Equus hydruntinus), wild-boars (Sus scrofa), hippopotamus (Hippopotamus amfhibius) and bovid (Bos primigenius) or in small sized animals as are rabbits (Oryctolagus cuniculus) and turtles (Testudo hermanni) and over bird remains as anatidae (Aythya sp. and Anas sp.) or doves (Columba sp.), within others.
We have also identified diagnostic elements of intentional bone breakage with the aim of extracting the bone marrow. These are percussion flakes and percussion notches. These elements appear in a major way over medium sized animals, like deer. The spatial distribution of the impact flakes show a concentration of these elements in the zone nearest to the hearths, which can be related to processing and consumption activities, in which they would use the fire to cook the food.
Activities related to the elaboration of lithic tools, also associated to the disposition of the hearths and coinciding with the faunal processing activities, occupy a major extension in these last lines. Major concentrations of remains are located in spaces nearest to hearths.
The distribution of the smaller elements in these zones reinforces the hypothesis of a good conservation in situ of the set, with the presence of areas of tool elaboration, transformation and revival. The documented cores present an advanced grade of use and in some cases have been reused and then abandoned on the spot. This concentration of lithic elements of small size, next to the emplacement of the used up cores and the presence of hammerstones, allow us to identify an area in which there has been an elaboration of tools, near hearths and probably related to other activities, like the processing of animals.
The identification of three lithic refits in this area, which establish short connection lines (less than a meter), reinforce the hypothesis of a good preservation of the studied set. These short distance refits are located in the areas with a major concentration of lithic remains of small size described previously as knapping areas.
Data given by the different studies which have taken place in level IV have allowed us to reconstruct the principal characteristics of their campsites and their occupational pattern, based in the establishing of durable occupations, which are probably reiterated spatially and temporally. These camp sites are organized in the cavity following complex patterns, related to the developing of daily activities delimited and associated to the use and location of the fire, similar to the ones observed in Neanderthal populations of a more modern chronology.
Human occupations 150.000-200.000 years ago, level XI
The habitat places can be occupied during a long period of time, or, on the contrary, be characterized by its temporal shortness. As it has been mentioned previously, this is a complex question in which the sedimentary formation processes normally make difficult the distinction of occupational units or events which form the archaeological level. On this line, the documentation on field of level XI has allowed the development of vertical projections (all the remains have been coordinated with independence of their size) which, waiting for a complete archaeo-stratigraphic analysis and of a systematic plan of refits, has allowed us to isolate occupational units inside this sedimentary packet.
The sedimentation ratio identified in this levels is high, and therefore, the burying of the remains has taken place with a relative rapidness, thus preventing weathering and preserving the original position of the remains, approximately. Only in specific zones localized under the cornice line, we have registered a slight movement of elements due to the intermittent dropping which would form gours modifying orientations and, specially, the slopes of some fossils (at a vertical level). Nevertheless, these phenomena wouldn’t produce watercourses which would provoke important movements of the material, as there is no evidence of the presence of abrasions, rounding or polishing as a consequence of this activity. With all this, the vertical distribution in some points of the excavated area warns of the existence of at least two occupational units. In other points of the excavation surface this evidence is not so easily observed and is less clear due to the compacting processes, dilatation and pressure of the sediments which were finally converted into small palimpsests.
But, these occupational units could be composed, each one, by one or various events. Parting from this idea, the vertical distribution of the modifications generated by carnivores, seem to be coincident with the end of both units. This phenomenon suggests, therefore, the existence of, as minimum, two moments of unoccupied moments by humans.
From the faunal point of view, the permanence in a shelter could favor the widening spectrum in the exploitation of the faunal remains and, therefore, translate this into a high specific diversity in the archaeological set. However, on level XI there is no record of a wide range of taxa which allow us to speak about this possibility (12 species). In the same way and in relation to this phenomenon, we haven’t observed either the development of various techniques of animal supply. The principal way for hominids in level XI of obtaining animal resources is by hunting.
For some authors, the presence of combustion structures is an evidence which establishes a temporal stability during occupations in archaeological sites. Nevertheless, some current hunter-gatherers have fires not only in their base campsites, but also in places with a very brief occupation, as for example, the high areas for hunting or on the temporal residence places where they only stay a few days. Following this evidence, combustion structures documented in level XI could answer to both an important occupational permanence as to a short settlement. However, the existence of certain variability in the processing of the ungulates, a limited taxonomic diversity, the development of a principal technique of procurement and a volume of material quite low, makes us think of a short-term occupation.
Briefness of human occupations in level XI is reinforced by the studies on lithic industry which show a marked decrease in cores and hammerstones in comparison with other levels (XII), as well as a major number of elements produced. This circumstance points towards a major representation of the final phases of the operative chain of the lithic industry. From this perspective, the lithic set from level XI allows us to infer about the presence of brief occupations clearly differentiated of the types of settlements documented on upper levels in the sequence which present a major duration and complexity in their activities (levels I to V).
By their side, levels XII-VII present lithic industry mainly worked on limestone, with numerous cores and hammerstones, a very low number of remains of debitage and very high configuration and transformation. Tools are: denticulate tools, lateral and deflected hand axes in flint, dorsal knives, flakes with retouch and calcareous denticulate macro-stone tools. In occupations of level XII, there are flakes with a cutting edge in limestone with very little retouch for a short and immediate use. The entrance of flint in occupations of levels VI-VIII makes the debitage products increase but with a strong decrease of transformations (retouched tools). These levels are considered brief or very brief occupations, maybe between spring and summer like some seasonal elements indicate, recovered in level XII- with a more or less selective hunting, opportunist in some occasions. Hunting is focused on red deer (Cervus elaphus) and especially on horse in level XII, and in a complementary way, in tar and aurochs. The exploitation of environments is mainly on plains (horse and aurochs), although ubiquitous taxa are always present.
Human occupations 350.000 years ago, level XVII
Level XVII of Bolomor Cave is the oldest stratigraphic sequence of the site with an anthropic fossil record. In base to sedimentological criteria, they have been divided in three sublevels XVIIa, XVIIb and XVIIc. Of these three, XVIIb is characterized by being a sterile archaeological layer which separates XVIIa and XVIIc in two different archaeological units. In this sense, archaeological material recovered is well delimited in two different sets.
We have to bear in mind diverse elements in order to find out the duration of these occupations. One of them is the volume of material recovered in relation to the sedimentation rate. In case of level XVII, this relation doesn’t present any value elevated for none of the sublevels. On the other hand, the presence of modifications generated by carnivores and birds of prey allow us to infer the existence of intermittent periods of no human occupation which seem to have been accentuated towards the end of the archaeological accumulation of sublevel XVIIc. In the same way, in sublevel XVIIa there are periods of abandonment of the cavity by hominids, which are used by non human predators. These periods without anthropic presence weren’t frequent or long due to the small proportion of alterations generated by carnivores, its high archaeo-stratigraphic dispersal and the absence of characteristic elements of dens on long time occupations.
If we part form the idea that the human permanence in a shelter allows a better dominion of the environment, and therefore, a wider spectrum of resources and techniques, level XVII doesn’t present an elevated taxa diversity (XVIIc 12 species and XVIIa 16 species) nor of obtaining methods. Hunting techniques are the most present both in sublevel XVIIa as in XVIIc. Therefore, it is possible that this limitation can answer to occupational dynamics with a less temporal history. Capturing of small preys, although they could have been obtained in an individual way, also needed the developing of different hunting methods (specially in the birds case).
Due to the reduced dimensions of the excavated area, it has not been possible to evaluate the degree of occupational complexity with spatial distribution on level XVII. However, data proportioned by lithic industry seems to show a principal occupational dynamic. So, prime materials (flint, limestone and quartzite) are the most diversified in the sequence, with a proportion of flint cores, remains of debitage and a high configuration and transformation. Tools are composed by lateral and deflected hand axes in flint, denticulate tools in quartzite, flakes with cutting edges opposite cortex and the presence of denticulate macro-stone tools in limestone. The presence of these elements and their relative frequencies suggest some less prolonged and less intense human occupations than those identified in the upper levels of the stratigraphic sequence, and most specifically, of the ones observed in level IV.
The access to the knowledge about human activities might possibly be one of the most attractive aspects, as it discovers our past and is the main objective of every prehistoric research. Through the archaeological study of diverse disciplines we try to reconstruct the processes and experiences of the past.
Hunting activities in Bolomor are the protagonist in the economic behavior related to the subsistence of human groups. Very far from being a simple process, as we continue to research we find great intensity and complexity in the behavior of human beings during those moments. The gathering of fruits and vegetables must be important too, as some stable isotopic studies wear-use and dental calculus analyses show.
Human groups of these chronologies are mainly itinerant, developing migrant circuits of exploitation of territories which they occupy during their journey. In Bolomor, at least, we have registered more than a hundred of these occupations which consist in using the cave as a habitat place (camp site or temporal refuge) to develop various activities in the nearby territory. In these occupations there is a developing of complex activities related to hunting processes, gathering, and food consumption, lithic knapping, combustion structure elaboration, etc. These groups had a sufficiently high number of individuals in order to allow their subsistence and the elaboration of strategies as complex as to multiple predations on horses in level XII.