Human Ecology of Reproduction in Nomadic Turkana Pastoralists

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In this project Dr. Leslie and his colleagues will conduct a biological study of Turkana pastoralists who live in the northern desert region of Kenya. The goal of the research is to understand Turkana fertility and the team will conduct a number of coordinated studies. Through menstrual diaries and salivary progesterone assay it will be possible to determine if and when women are fertile, determine individual cycle length and what percentage of the adult female population is fertile. To understand the causes of observed patterns a number of ancillary studies will also be carried out. Data will be collected on health and nutritional status and it will be determined how these vary over the course of the year. Measurement will be taken to determine body composition and activity patterns and energy expenditure will be observed. Since ties have been established between breast-feeding and fertility, breast-feeding patterns will also be studied. The Turkana are an extremely interesting population from a demographic perspective. They are pastoralists who depend on their herds of camels, cows, goats and sheep for food. They live in a harsh desert environment which receives limited amounts of rain only at specific times of the year. Therefore they are subjected to severe stress during some seasons and milder stress during others. Previous work has shown that their energy intake is low. However (perhaps because of high protein intake) the average fertility level is extremely high. Also it is extremely seasonal. The purpose of this study is to document this further and determine the causes. This research is important for several reasons. It should provide additional understanding of the natural processes which control fertility. Secondly, although the Turkana live in a highly stressful desert environment, they have adapted to it extremely well. In other environmentally similar areas of Africa, when drought strikes, people starve unless the international community provides food. The U.S. government expends large sums for this purpose. Hopefully what is learned about Turkana adaptation can serve a useful function elsewhere in Africa.