With funding from the National Science Foundation, Drs. Lawrence H. Robbins and George A. Brook, together with colleagues and students will investigate the initial spread of domesticated livestock into southern Africa. This project will be the first collaborative interdisciplinary approach to the above problem carried out in an area of northern Botswana that is believed to have served as a gateway for the spread of livestock. The project will combine archaeological and paleoclimatic research and will further international cooperation and training because fieldwork will be carried out with personnel from the National Museum of Botswana.
In southern Africa, domesticated cattle, sheep and goats are of major importance in the food economies, social contexts and environmental adaptations of many people, both past and present. However, certain basic questions regarding the origins of livestock in the region remain unanswered such as where and when did they first enter southern Africa? In addition, there is considerable interest in whether variations in climate influenced their arrival and dissemination. A cooler climate would have reduced the extent of the Tsetse fly infested area just to the north of the research area and made it easier for livestock to be introduced. Cattle cannot survive in this area today. However, the role of climate change in the dissemination of livestock has not yet been documented in the southern African region. This research will investigate the above questions by conducting archaeological excavations at sites near Lake Ngami in the Kalahari Desert. Historical linguistic studies have revealed that the Lake Ngami area served as an important point of entry, or gateway for the initial spread of livestock into southern Africa. Archaeological research will verify whether the linguistic theory is correct.
Preliminary archaeological work has demonstrated that the sites selected for further excavation span the critical period from when people subsisted entirely by hunting, fishing and foraging for wild foods through the period when the first livestock appeared. The research will document this transition in several innovative ways. The bones of domesticated livestock will be dated by the AMS (accelerator mass spectrometry) method of radiocarbon dating to develop a precise chronology for their first appearance. In addition, an important type of pottery, known as Bambata Ware, that is believed to be a marker of the earliest livestock herders in southern Africa will also be dated by this technique for the first time. Some dated pottery will be subjected to casein analysis in order to reveal whether the early stock herders practiced milking.
The role of climate will be investigated in several ways. The changing characteristics of sediments exposed by our excavations, along with studies of variations in the level and extent of Lake Ngami will provide information on climate changes near the archaeological sites over the last several thousand years. A chronology for these changes will be obtained using optically stimulated luminescence dating (OSL) which can date sands and other clastic sediments. This record will be compared and augmented with high-resolution climate data for the same time period from stalagmites recovered from Drotsky's Cave located to the west of Lake Ngami. Resulting rainfall and temperature records will be used to assess the role of climate in the introduction of livestock to southern Africa.
