2 Material and methods
Excavations in the Lower Rhine basin have yielded the human skeletal remains of c. 150 individuals (table 1). The human bones from the Late Mesolithic and Middle Neolithic sites present a range from more or less complete articulated skeletons, recovered from graves, to single isolated bones scattered in the refuse deposits. Late Mesolithic sites are Polderweg, De Bruin and Mariënberg. Cremated remains are known from this period at Dalfsen and from the Middle Mesolithic period at Oirschot. The early Neolithic period is dated 5300-4300 cal BC in the Netherlands, but agrarian communities (Bandkeramik, Großgartach, Rössen) are restricted to the extreme southern part (South Limburg) in this era. No human skeletal material has been preserved in Bandkeramik cemeteries. Communities in the study area were foragers and, from 5000 cal BC onward, ceramic and on that basis considered to be Early Swifterbant. There are no burials in the study area related to these communities. The Middle Neolithic sites belong to the middle phase of the Swifterbant culture (the Swifterbant sites, Urk and Zoelen) and the Hazendonk group (Schipluiden and Ypenburg). It should be noted that the isolated remains from the phases 2 and 3 (N=10) of the Hardinxveld sites are included in the Late Mesolithic sample. These phases are ceramic (Early Swifterbant) but non-agrarian and should as such be considered as (final) Mesolithic.
Table 1 Human remains from the Lower Rhine Basin c. 5500-3500 BC.
The site locations are indicated in figure 1. The treatment of the dead is studied in relation to their archaeological context, like grave types and goods, and the nature of the find (complete burials or isolated bones).
The demographic analysis aims to reconstruct the group composition and thereby to contribute to the functional interpretation of the sites. The basic parameters are based on the physical anthropological publications of the human remains, which comprises age and sex diagnosis. Methods of anthropological age determination represent a biological age, which can only serve as a rough estimate for the real chronological age. Aspects like heath and diet, lifestyle and genetic factors influence the aging process and therefore show a strong individual variety, especially for the adult age groups (e.g. Kemkes-Grottenthaler 2002). Therefore the results have to be assessed with caution. Another point in this respect is the fact the physical anthropological investigations were performed by different scholars during a considerable time span and with the application of different methods. The demographic parameters are presented but the analysis of the populations will be mainly based on the percentage of subadults (below the age of 20 years at death) versus adults. The demographic comparison with other Mesolithic and Neolithic populations in Europe will be directed at the proportion of juveniles between 5 and 19 years at death. The age category 0-4 years is excluded because children from this age group are mostly underrepresented in cemetery populations. The proportion 5-19 years is calculated by dividing the number of individuals from 5-19 years with the number of individuals from the age of 5 onwards, 15 P 5 = d(5-19)/d(5+) (Bocqet-Appel & Paz de Miguel Ibánez 2002). This proportion is correlated to fertility, as a high mortality rate means a high birth rate as well, and is therefore used as a means to establish the growth rate of a population.
The demographic data indicate, whether the sites were inhabited by family groups. This aspect focuses on the function of the sites, especially base camps versus specialised extraction camps. Not only is the age at death relevant in this respect, but also the recovery of shed milk teeth, showing that children were living at these locations. They are of no importance however for the mortality profile of the populations.
The topic of health is approached by other aspects of the anthropological study, namely the evaluation of paleopathological phenomena associated with diseases, physical stress, trauma, and the stature of adult individuals. Chronological trends in stature can be related to changes in economy and the associated health of the people (Roede & Van Wieringen 1985; Maat 2005).
Considering the composition of the populations it is interesting to know whether these people were all local or if any outsiders were present. Of course being ‘foreign’ can be reflected in the variability in the treatment of the dead; aspects like burial type, grave goods of a special (foreign) nature, position of the body, can be taken into account but the interpretation of these traits is not unambiguous and the relevant evidence is restricted in our case. Chemical analysis of bone tissue, especially dental enamel, offers an opportunity to pinpoint immigrants in a population by way of their isotopic make-up and therefore it is desirable to incorporate chemical analysis in the study of mortuary variability and of human skeletal remains in general.
Biochemical analyses of the human bones have been applied to reconstruct aspects of the diet as well. By carbon (δ13C) and nitrogen (δ15N) analyses the composition of the protein part of the diet was investigated (contribution by J. van der Plicht).