Dietary choices of the pouched mouse (Saccostomus mearnsi) in central Kenya

Although there is growing recognition of the importance of small mammals in savanna ecosystems of east Africa, the ecology and behavior of these organ isms are nor well known. We conducted studies on the dietary preferences of one rodent, the pouched mouse (Sacrostomus mearnsi), which is the dominant small mammal in a widespread habitat in central Kenya. To establish the fo od preferences of this species, we: (1) conducted cafeteria trials in the l aboratory whereby individual mice were offered seeds and a selection of her baceous vegetation from the habitat; (2) surveyed the habitat for piles of vegetation clipped by these mice and identified these clippings to species; and (3) estimated the abundance of plant species in the habitat to determi ne if the mice were clipping species in proportion to their availability. O ur results indicated that S. mearnsi prefers green vegetation to seeds, at least during wet seasons, and that it has a strong preference for forbs. In cafeteria trials, S. mearnsi chose 93 percent green vegetation and only 7 percent seeds. The forb Commelina africana was highly preferred over other food items offered. In the habitat, two forbs, C. aifricana and Monsonia an gustifolia, constituted > 40 percent of the piles of clippings, although th ese two species together made up > 4 percent of the available vegetation. G rasses also were clipped frequently, although in lower proportions than the ir availability in the habitat. The herbivorous habits of S. mearnsi establ ish the potential of this species to compete for resources with ungulates, which are abundant in this habitat.