The *nomadism of many *hunting and gathering and *pastoral peoples is an adaptation to the variable availability of basic resources, such as the animal species hunted, the plant species gathered, and the pasture and water for herded livestock. Technologies of production, such as hunting weapons or selection for livestock breeding, and technologies of *consumption, such as temporary or mobile dwellings, are closely tied to this adaptation. Nomadic pursuit of resources requires flexible composition of local groups, which often fragment into smaller units and then reunite, with individuals and families moving in and out of the group. Because nomadic mobility makes monopoly over resources and coercion difficult, political leadership and decision-making tend to be consensual. Demographic behaviour is also linked to this adaptation: for example, the practice of female †infanticide among some Arctic Inuit groups in response to the high death rate of male hunters, aims to provide a balance of adult females and males in an ecosystem where hunter/non-hunter imbalance means starvation.