Dietary Choice of a Generalist Grassland Herbivore, Sigmodon hispidus

Abstract

Dietary choice as well as the nutritional and perceptible characteristics of known dietary items were determined for cotton rats (Sigmodon hispidus) on the Texas coastal prairie. The nutritional landscape of the coastal prairie is dynamic: monocots are abundant, dispersed in clumps, and exhibit relatively little seasonal variability; by contrast, dicots are highly variable both spatially and temporally. The lower green stems of four species of grasses constitute the bulk of the cotton rat diet; however, some plant parts of dicots are always ingested. Parts of plants with high soluble-carbohydrate content and short-handling times were selected by cotton rats; however, these same parts of plants typically were low in protein and phosphorus content.