Refuge microclimates of rodents: a surface nesting Otomys unisulcatus and burrowing Parotomys brantsii

We investigated microclimates of the nest of Otomys unisulcatus Cuvier, 1829 and the warren of Parotomys brantsii (Smith, 1834) during two seasons and correlated these with the rodents' physiology. In both rodents' refuges, temperature varied less than ambient temperature (TA). In winter, temperatures in the O. unisulcatus nest at 40 cm below the nest apex, and in Lhe P. brantsii warren 15 cm below the soil surface, were higher than noclurnal TA. In summer, during the hours of highest TA, refuges wore cooler than TA. Vapour pressure (v.p.) in the refuges varied less and was higher than ambient v.p. In the humid refuges, heat loss by conduction rather than evaporative water loss is suggested. The nest of O. unisulcatus, with less tem­perature variation in winter and lower temperatures in summer, was less dependent ofTA than P. brantsii's warren. The use of these refuges therefore contributes to the survival of those mesic rodents in a semi-arid region.