Ecology and behavior of the pouched mouse, Saccostomus mearnsi, in central Kenya

Abstract

I investigated the ecology and behavior of Saccostomus mearnsi, a medium-sized semi-fossorial murid rodent for 15 months in a tropical savanna of central Kenya. This poorly known species is the dominant small mammal in this widespread habitat, although it has never before been reported in high local abundance. On three replicated 1-ha grids, S. mearnsi exhibited a 2.5-fold change in abundance over 15 months from 16 ± 3.5 (SE) to 42 ± 7.5 individuals/ha. S. mearnsi had strongly seasonal reproduction, with almost all females in breeding condition following the rainy season, while only 10% were in breeding condition during the dry season. Eighty-five percent of males, however, remained in breeding condition throughout the year. Adults of both sexes exhibited great variation in body weight (males, 48-121 g; females, 39-94 g). There was significant seasonal variation in body weight for both sexes. Home ranges of males (0.21 ± 0.02 ha) were three times the size of those of females (0.06 ± 0.01 ha), and the average of the maximum distances moved by males between captures varied significantly between seasons. Analyses of stomach contents showed that S. mearnsi was omnivorous, consuming primarily forbs during the dry season and seeds following the rains. Adults share burrow entrances in termite mounds; whether or not they nest individually or communally remains to be determined.