UC Santa Cruz
Mobility and Herd Management Strategies of Early Pastoralists in South-Central Kenya, 3000-1200 BP
- Author(s): Janzen, Anneke
- Advisor(s): Gifford-Gonzalez, Diane
- et al.
Specialized pastoralism emerged in Kenya around 3000 years ago and has evolved with changes in the social and ecological landscape to this day. Ethnographic research has documented significant changes in herding strategies among pastoral groups throughout colonial and post-colonial periods. Stable isotope analysis sheds light on how crucial mobility was in maintaining herds before the appearance of iron-using and –producing peoples in the region. This thesis explores the use of multiple stable isotopes to reconstruct mobility and herd management strategies of ancient pastoralists in south-central Kenya 3000 to 1200 years ago. Through intra-tooth sequential sampling of livestock tooth enamel, which presents an isotopic record of diet during tooth formation, movements across the landscape may be tracked. Further zooarchaeological analyses of livestock teeth include analysis of mortality profiles generated from age estimates based upon life histories. Combined with enamel hypoplasia data, these analyses inform on herd management strategies of early pastoralists.
Archaeological cattle and caprine teeth from seven Savanna Pastoral Neolithic sites in the Central Rift Valley and neighboring plains of Kenya were sequentially sampled and analyzed for their carbon, oxygen, and strontium stable isotopic composition. Consistently elevated carbon stable isotope ratios did not indicate any herding at high elevations. Because the lack of altitudinal mobility does not preclude extensive herding and exchange of livestock long distances at low elevations, a strontium map of south-central Kenya was created by analyzing the stable strontium isotope composition of archaeological and modern microfauna collected from various locations throughout the Central Rift valley and adjacent mountain ranges and plains. 87Sr/86Sr ratios, which can reflect movement across geologically distinct soil complexes, also indicated low levels of seasonal or long-term mobility, with little evidence for exchange of livestock among far-flung herding groups, though some regional differences exist. In contrast to widespread seasonal mobility and exchange documented ethnographically, these data show that those patterns were not in place before agricultural populations moved into the region.
The mortality data presented for all definite pastoralist sites show that early herders kept cattle alive for somewhat longer than East African pastoralists do today, and that some variation in management techniques is apparent, perhaps due to environmental or cultural factors. Mortality profiles and hypoplasia data from livestock are quite similar between pastoralist sites and one with a mixed faunal assemblage, indicating that site with higher proportions of wild fauna was indeed occupied by pastoralists taking advantage of seasonally available migratory wild animals, suggesting some fluidity in subsistence strategies.