Since the late 1970s, cattle raiding with automatic weapons has escalated among nomadic herding societies in northern East Africa. We examine the impact of AK-47 raiding on the adaptability of Karimojong agropastoralists in northern Uganda. Most notably, raiding is linked to a loss of population resilience in Karamoja, measured in increased mortality of young children and of adult males in their prime reproductive years and decreased female fertility. AK-47 raiding has acted both directly and indirectly as a Darwinian stressor in this population, compromising long-standing adaptive strategies and intensifying selection pressure. We briefly discuss similar effects of recently altered patterns of raiding among related Turkana pastoralists in Kenya. We then consider the process by which this traditional cultural institution was modified in the interests of preserving cultural identity. We conclude nonetheless that cattle raiding with automatic weapons constitutes singularly maladaptive cultural behavior in contemporary pastoralist societies. Indeed, it represents the single greatest threat to their biobehavioral resilience and ultimately may have profound evolutionary costs in terms of pastoralists' survival. I. We are indebted to the Karimojong women who spoke with eloquence and honesty of the deaths of so many of their parents, husbands, siblings, and children during the terrible closing decades of the 20th century. Their stories were united by stark themes of violence that overshadowed all other considerations, compelling us SANDRA GRAY is

Variation in the duration and pattern of breast-feeding contributes significantly to inter-population differences in fertility. In this paper, measures of suckling frequency and intensity are used to compare the effects of breastfeeding practices on the duration of lactational amenorrhoea, and on the length of the birth interval in three prospective studies undertaken during the 1980s, among Quechua Indians of Peru, Turkana nomads of Kenya, and Gainj of Papua New Guinea.In all three societies, lactation is prolonged well into the second year postpartum, and frequent, on-demand breast-feeding is the norm. However, the duration of lactational amenorrhoea and the length of birth intervals vary considerably. Breast-feeding patterns among Gainj and Turkana are similar, but Turkana women resume menses some 3 months earlier than do the Gainj. The average birth interval among the Gainj exceeds that of nomadic Turkana by over 15 months. Suckling activity decreases significantly with increasing age of nurslings among both Gainj and Quechua, but not among Turkana. Earlier resumption of menses among Turkana women may be linked to the unpredictable demands of the pastoral system, which increase day-to-day variation in the number of periods of on-demand breast-feeding, although not in suckling patterns. This effect is independent of the age of infants.The short birth intervals of Turkana women, relative to those of the Gainj, may be related to early supplementation of Turkana nurslings with butterfat and animals' milk, which reduces energetic demands on lactating women at risk of negative energy balance.

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Recent research has shown that significant variation in breast-feeding behavior exists among natural fertility populations, all of whom have been characterized as practicing "on-demand" breastfeeding. A number of recent prospective studies have contributed to a better understanding of breastfeeding structure and of its consequences for population differences in fertility. Currently, there is a growing interest in quantifying the complex environmental and biocultural interactions which influence that structure; in other words, in establishing an ecology of breastfeeding. In this paper, a carefully structured retrospective study of breastfeeding behavior among nomadic Turkana is used to identify environmental, biobehavioral, and socioeconomic factors associated with variation in breastfeeding frequency among Turkana women. In agreement with the results of a prospective study conducted as part of the same research, the age (growth) and physical development of nurslings show significant correlations with breastfeeding frequency. Maternal physical status, the depth of the maternal social network, and, to a lesser degree, rainfall patterns are also significant. All of these factors appear to influence breastfeeding through their effects on maternal participation in herding activities and related absences from camp. Finally, the study also presents new strategies for collecting and utilizing retrospective data, which are notoriously unreliable and difficult to classify according to operational definitions recently developed for prospective studies. Results of the present study suggest methods by which the quality and reliability of recall data may be enhanced.

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