5 Physical anthropology: demography and health
5.1 Sex and age profilesnext section
The sex and age profiles of the sites presented here are statistically divided in intervals of 5 years (Acsádi & Nemeskéri 1970, 62). Normal versus abnormal profiles will be discussed especially for the proportion of immature individuals. The sites and corresponding demographic data are divided in three groups, based on their age and geographic setting, each comprising two sites: 1) the Late Mesolithic sites, dating from c. 5500-4500 BC, namely Hardinxveld-Polderweg and De Bruin in the Dutch river area. 2) Swifterbant and Urk, dating from c. 4200-4000 BC and located in the middle of the Netherlands (the IJsselmeer Basin), and 3) Schipluiden and Ypenburg, both occupied at c. 3500 BC in the western coastal area. The graphs (Figs. 2-4) display the total number of individuals per age interval, as well as the number of adult male and female individuals.
The mortality curve of Hardinxveld-Giessendam is based on 19 people, 3 females, 8 males, 5 adults of unidentified sex and 3 children and subadults up to 20 years. The last group comprises c.15 % of the total population (fig. 6). The mean age at death for the adults was c. 43.5 years (women 43.3 and men 43.6 years). The presence of shed milk teeth shows, that the sites were used by family groups, including women and children. In view of these data one can conclude that these river dunes were inhabited by families and therefore served as a base camp.
At Swifterbant and Urk data on sex and age of a total of 69 individuals were available for the mortality profile. This group of adults consists of 10 men, 14 women and 30 individuals of unknown sex. Children and subadults (N=15) make up c. 22 % of the population (fig. 7). The mean age at death for the adults was c. 38 years (women 39.6 and men 36.3 years). The presence of women and children is consistent with the occupation of these sites by family groups. The total number of individuals at Schipluiden and Ypenburg amounts to 56, with 16 men, 11 women and 6 individuals of unknown sex. The mean age at death here is 38 years (women 33.5 and men c. 41 years). The percentage of children and subadults is, at c. 42.3 % much higher here (fig. 8). It seems that all members of the local group, the children below 5 years of age included, were buried in the Ypenburg cemetery during a certain stage of the occupation of the dune, irrespective of sex and age. Family groups must have occupied both sites, in view of the presence of children, but the number of women in Schipluiden is too low for a natural population. Evidently the small cemetery site on this dune does not reflect all the mortuary practices as the many isolated bones also indicate an above-ground ritual with disposing the dead, which left hardly any archaeologically detectable remains.
The mortality profiles of the various populations are shown in figure 9. The percentages of young children and subadults are much higher for the combined series of Schipluiden and Ypenburg. The profiles of Hardinxveld-Giessendam, Swifterbant and Urk show an unnatural composition in this respect. Several factors could be responsible for this, such as preservation conditions, which can be unfavourable for young children, and an archaeologically elusive treatment of the dead. This restricts a comparison at the level of demographic analyses. The limited demographic data from these sites may, however, serve as a means of typifying the kind of settlement, to establish whether these were occupied by (complete) families or not. The data from Schipluiden and particularly Ypenburg give a fuller picture of the population structure, especially by the formal burials of young children. In terms of the adult-subadult ratio the data from these two sites show the most normal mortality curve with more than 40 % of individuals classified as subadult.
Skeletal remains can reveal some aspects of a person’s health, but only some, as especially chronic diseases can lead to bone alterations, in contrast to short-term ones. The cause of death is rarely detectable from the skeleton. Pathological bone changes can be associated with a wide variety of phenomena such as bad health, hard physical labour and infectious diseases. Preservation will also affect the possibilities for observation; for instance, if spongy skeletal parts like the vertebral column and the joints of the appendicular skeleton are badly preserved no information on physical stress can be recorded.
At Polderweg pathological bone changes were not present. The preservation of the skeletons at Urk made any observations impossible. Swifterbant offers slightly better circumstances, some pathologies of a diverse nature were observed there, three of which involved peripheral arthritis. The population from Ypenburg appears to be best suited for the study of health. Enamel hypoplasia, a condition associated with spells of bad health during childhood (Hillson & Bond 1997), was observed in six cases there. Degeneration of the spine and peripheral joints (vertebral osteoarthritis and peripheral osteoarthritis) is the main feature present in the populations of Schipluiden (4 individuals) and Ypenburg (14 individuals). At both Schipluiden and De Bruin one incidence of trauma of a violent nature was recorded. This is probably the tip of the iceberg as lesions to the soft tissues like the organs cannot be studied. Dental pathology, especially caries, which is generally associated with diets rich in carbohydrates (Hillson 1979), was not observed in any of our populations. This may, however, be obscured in cases of heavy attrition of the teeth.
The pathological features are on the whole inconclusive for the general health status, but the observations of those individuals that endured hard physical labour give at least an impression of the heavy daily workload corresponding to an agricultural way of life.
Information on stature is not available for all the groups discussed here. The data are shown in table 3. The preservation at Urk and Swifterbant made measurements for the calculation of statures impossible. For the women and men from Ypenburg stature seems to have been relatively small in comparison to the Late Mesolithic female skeleton of Polderweg and the values for the men at Schipluiden (table 3). The sparse data should, however, not be considered as representative, but more as indicative.