Resource Partitioning in Sympatric Populations of Collared Peccaries and Feral Hogs in Southern Texas

Species introduced into systems with ecologically similar species are predicted to compete or undergo niche compression to allow coexistence. We examined space, time, and diets of the realized niches of two suiforms, native collared peccaries (Tayassu tajacu) and introduced feral hogs (Sus scrofd), in sympatry in southern Texas in 1991–1992. Eleven females (six peccaries, five hogs) representing distinct herds were outfitted with radiotrans-mitters. Patterns of habitat use varied (P< 0.001) between species, with peccaries selecting chaparral plant communities and hogs selecting mesquite (Prosopis glandulosa) communities. Overlap in use of habitat was greatest during winter and lowest in spring. Predominantly crepuscular patterns of activity were exhibited by both species, with lowest overlap in activity occurring during winter. Grass was dominant in fecal samples of hogs during autumn, winter, and summer, and forbs were dominant in feces of peccaries in all seasons. Overlap in diet was most apparent during spring (100%) and least apparent during autumn (36%). High seasonal overlap on one axis of niche space was balanced by low overlap on other axes. Different patterns of habitat and diet selection combined with similar activity patterns were consistent with differences in cranial anatomy, digestive function, and eco-physiology between hogs and peccaries. Conditions providing competitive advantage to peccaries are predicted to be dense scrub cover and presence of succulents, whereas hogs may be favored by presence of free water and more open brush-savanna habitats.