In 2009, Witsenburg and Adano summarized their research on rainfall variability and livestock raiding in Marsabit District, Kenya. They found that livestock-related violence was higher in wetter months and wetter years, contrary to the common assumption that scarcity of water and pasture is the primary driver of livestock violence. Our research, focusing on the neighboring Turkana District of northwestern Kenya, attempted to replicate the Witsenburg and Adano findings for the years 1998-2009. We find significant relationships between rainfall variability and intensity of livestock violence, but in the opposite direction-drier months and drought years in Turkana District have higher intensities of violence.

We have known for some time that complex societies are more likely to have land tenure systems based on private rights and less likely to have communal ownership. Less understood is why. More specifically, what are the mechanisms to explain why complex societies have more private property? What are the adaptive advantages of one system rather than the other? Conceptualizing and coding land tenure systems as a "bundle of rights," this worldwide cross-cultural study suggests that Acheson's (2015) economic defendability theory in conjunction with some environmental stressors, such as drought, may help us understand cross-cultural variation in land tenure systems. Our results have evolutionary implications. They suggest that if property rights were claimed, communal property systems would have been the default system for any society having substantial degrees of hunting, gathering, or herdable animals. Agriculture by itself is not a strong predictor of private land rights, although irrigation agriculture is. [land tenure systems, defendability, resource stress, cross-cultural] RESUMEN Hemos sabido por algún tiempo que las sociedades complejas tienen más probabilidad de tener sistemas de tenencia de la tierra basados en derechos de propiedad privada y menos probabilidad de tener propiedad comunal. Menos entendido es el por qué. Más específicamente, ¿cuáles son los mecanismos para explicar por qué las sociedades complejas tienen más propiedades privadas? ¿Cuáles son las ventajas adaptativas de un sistema en lugar del otro? Al conceptualizar y codificar los sistemas de tenencia de la tierra como un "conjunto de derechos," este estudio transcultural sugiere que la teoría de la defendibilidad económica de Acheson (2015) junto con algunos factores que causan estrés ambiental, como la sequía, pueden ayudar a entender la variación transcultural en sistemas de tenencia de la tierra. Nuestros resultados tienen implicaciones evolucionarias. Ellos sugieren que, si los derechos de propiedad fueron reclamados, los sistemas de propiedad comunal podrían haber sido el sistema por defecto para cualquier sociedad teniendo grados sustanciales de caza, recolección o animales de pastoreo. La agricultura por sí misma no es un predictor fuerte de los derechos de propiedad privada de la tierra, aunque la agricultura con irrigación lo es. [sistemas de tenencia de la tierra, defendibilidad, estrés en los recursos, transcultural] F or more than two millennia, beginning from Greek and Roman times, scholars have been intensely interested in conditions that led to the origin of different property regimes (Engels and Hunt [1884] 2010; Rudmin 1988, 1992a). As summarized by Rudmin (1988), much of the debate concerned whether landed property should be held privately by household heads and entitled heirs or commu

This article argues that Ethiopia's agricultural extension program, which received more government funding and donor support than other similar programs in Africa, reinforced the rural presence and authoritarian powers of the ruling party while largely failing to improve smallholder agriculture. The principal reason for this outcome has to do with the systematic entanglement of the Green Revolution package delivery system with the immediate goal of guaranteeing the party's political security. In one Amharic-speaking community that provided ethnographic information for this article, overzealous party leaders rewarded supporters at the expense of imagined opponents. This distortion, coupled with a culturally embedded concept of success (defined as upward mobility), caused pervasive fear, insecurity, suspicion, and rivalry among farmers. Not surprisingly, this insecurity has a deleterious effect on hardworking farmers. The article suggests that any meaningful attempt at improving the program must recognize the centrality of politics, especially at the community and household levels, where parochial interests interface with cultural expectations.

Previous research on warfare in a worldwide sample of societies by Ember and Ember (Journal of Conflict Resolution, 36, 242-262, 1992a) found a strong relationship between resource unpredictability (particularly food scarcity caused by natural disasters) in nonstate, nonpacified societies and overall warfare frequency. Focusing on eastern Africa, a region frequently plagued with subsistence uncertainty as well as violence, this paper explores the relationships between resource problems, including resource unpredictability, chronic scarcity, and warfare frequencies. It also examines whether resource scarcity predicts more resource-taking in land, movable property, and people, as well as the commission of atrocities. Results support previous worldwide results regarding the relationship between resource unpredictability and warfare frequency. Results regarding resource-taking and atrocities are more nuanced and complex. In almost all findings, relationships are generally in opposite directions in nonstate and state societies. In post-hoc analyses, atrocities are significantly more likely to be committed in states than in nonstates.

Focusing on livestock raiding, a major form of violence in arid and semiarid regions, we evaluate the relationship between rainfall and intensity of violence, disaggregating ethnic groups that have somewhat different subsistence patterns. We do so to try to resolve previously published results and conclusions that appear contradictory -some research finding livestock violence higher in wet times suggestive of more violence in times of plenty; others finding violence higher in dry times suggestive of greater scarcity. Using rainfall from NASA and violence data from ACLED for the years 1998 -2009, we looked at the patterns of livestock-related violence for six different ethnic groups that have a home in the area in and around Marsabit district of Kenya. Different ethnic groups appear to have somewhat different patterns and we suggest how some of their cultural differences may explain these patterns. However, for most groups, intense violence is more common in drier times.