Macro- and micromorphological features of lifestyle differences in pigs and wild boar

It is known that since the beginnings of domestication human communities have, in one way or another, restricted the activity of their livestock in order to gain better control of the animal management process. The exact nature of this human-animal relationship, however, is difficult to assess from faunal remains in the archaeological record through conventional methods. Taking suids as an example, we propose a novel approach to detect differences in activity patterns of animal domesticates using features of cross-sectional geometry (CSG) and histomorphometry. The present study analysed mid-shaft tibia samples from free-ranging wild boar (n = 40), domestic pigs raised indoors having limited mobility (n = 24) and pigs raised outdoors, free to roam in a paddock (n = 15). Geometric features were found to differ between wild boar and both groups of domestic pigs with regard to the amount of cortical bone (higher in wild boar) as well as in the shape of the bone cross section (more triangular in wild boar). The density of secondary osteons was higher in wild boar than in both groups of pigs. The results were controlled for possible effects of age and weight of the animals and, even though some variables co-vary with these growth-dependent measures, the overall trend of a clear association between activity levels, CSG and micro-morphology can be validated. Thus, the study demonstrates the potential for detecting husbandry systems through the analysis of activity levels reflected in the combined assessment of gross and histo-compositional morphology of a load-bearing long bone.