Turkana of northwestern Kenya are responding to environmental changes and continued marginalization by government and international development at both the household and individual level. The diverse livelihood strategies used by Turkana suggest that local knowledge and behavior patterns enable continued existence in a harsh and unpredictable environment. Turkana local ecological knowledge is explored through interviews and collection of specimens in order to assess knowledge of wild foods that offer important nutrients to a pastoralist diet. This dissertation uses a livelihoods framework to understand what the strategies are and how the portfolio of strategies has changed in response to external influences. Economic theory informs analysis of how Turkana value the diverse species in their herds and how diverse strategies affect health and nutrition outcomes. At an individual level the contributions of children are evaluated through direct observation and ultimate benefit is ascertained using anthropometrics and nutritional status. Household ecology of complex pastoralist households is incorporated in to research design, methods of data collection and analysis. This research focuses on middle childhood, the period between four and twelve years of age, bridging the gap between child-focused feeding programs and adolescence. Children with a lower birth order demonstrate better nutritional status than more senior siblings, especially in girls, suggesting that gender roles have an effect on nutritional status during childhood. The biological tradeoffs involved in growth, development and health are evident in Turkana nutritional status through the lifespan. Some of the external influences on Turkana livelihoods include government and non-government organization programs of relief and development, which are addressed in discussion throughout each chapter. Turkana display cultural and biological plasticity that allow them to continue to survive in a harsh and unpredictable environment. By understanding some of the challenges Turkana face in maintaining livelihood portfolios in a changing environment, policies and programs will have more success as well as theory and practice of social science research on risk management through diversification, pastoralist resource management, biological development and nutrition in unpredictable environments and child development.