Spatial Use and Group Dynamics of Sympatric Collared Peccaries and Feral Hogs in Southern Texas

Abstract

Range and group dynamics of collared peccaries (Tayassu tajacu) and feral hogs (Sus scrofa) on the Welder Wildlife Refuge near Sinton, Texas, were studied during June 1991– November 1992. Eleven females (six peccaries, five hogs) representing distinct herds were outfitted with radiotransmitters. Crude densities of peccaries and hogs were estimated at 2.0 and 9.5 animals/km2, respectively. Peccary herds were highly cohesive units, in contrast to hogs, which exhibited a flexible grouping pattern. Ecological density of peccaries appeared to be negatively related to the density of observations of hogs within individual territories of peccaries. The distribution of group sizes also differed for peccaries in areas of low abundance of hogs (two herds) and in areas of high abundance of hogs (four herds). Size of home ranges did not differ between species. Home ranges of both species were larger during summer than spring. Overlap occurred between ranges of peccaries and hogs, but was diminished at the level of 75 and 50% core areas. Peccaries have declined on the study area for nearly 30 years, and feral hogs may have been involved in reducing herd and group size of peccaries.