Success in competition for a limited food resource can be determined in part by how efficiently a species digests food. We conducted in vivo trials to compare digestive performance by a guild of mast-consuming species in southern Texas: wild boar (Sus scrofa), white-tailed deer (Odocoileus virginianus), collared peccary (Pecari tajacu), wild turkey (Meleagris gallopavo), raccoon (Procyon lotor), and southern plains woodrat (Neotoma micropus). Four individuals of each species were fed commercial pellets and chromium-marked fiber to determine rates of passage. Dry matter and intake of digestible energy, and digestibility of detergent fiber, crude protein, and gross energy (metabolizability for turkeys) were determined for each species. Mean retention and time of passage of 95% of marked fiber were calculated. Digestibility and time of retention by wild boars was similar to foregut-fermenting species and equal to or greater than smaller hindgut fermenters. White-tailed deer and collared peccaries showed similar capabilities of digestion and retention, and also had higher digestibilities of fiber than small hindgut fermenters. Turkeys and raccoons had fast rates of passage and showed little digestion of fiber. Southern plains woodrats had intermediate digestibilities and times of retention. Wild boars are expected to be effective competitors for mast because of their digestive efficiency, large body size, and potential for consumption of large quantities of food.