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The dynamics and demography of gerbil populations at three study sites in the Namib Desert dunefields are reported. Low and fluctuating rodent biomass resulted from low primary and insect productivity caused by extremely low levels of precipitation. Reproduction was strictly seasonal and temporally associated with the occurrence of seeds in the diet. However, although seeds likely triggered reproduction, they did not sustain breeding. The gerbils were primarily insectivorous but also consumed some green plant material. Insects supply the protein, and plant tissues the vitamins and minerals, necessary for the maintenance of reproduction. Precipitation drove the system, regulated primary production, and hence determined gerbil population dynamics; plane of nutrition or a reproductive trigger initiated breeding, but requires experimentation. Juvenile recruitment was postponed, despite an apparent sufficiency of food resources during reproduction, and was likely inhibited by reproduction-related aggression of adults. Extrinsic and intrinsic factors are implicated in controlling the demographic processes of gerbils in the Namib Desert dunefields.