Sociality in molerats : Metabolic scaling and the role of risk sensitivity

The foraging behaviour and diets of the various bathyergid molerat species are reviewed briefly, and inferences are drawn concerning their dietary specialisation. A simple model has been constructed which investigates the risks of unproductive foraging by specialist feeders as a function of resource dispersion characteristics and group size. The model suggests that the principal benefit of group foraging is a reduction in foraging risk, rather than increased resource procurement per se. Meeting the energetic costs of non-workers in social groups necessitates a reduction of the total energetic expenditure of the colony. This is achieved by reducing body size, huddling in the nest, and scaling mass-specific resting metabolic rate virtually independent of mass.