Reproduction of Feral Pigs in Southern Texas

Abstract

The feral pig (Sus scrofa) is an abundant introduced species with pernicious effects on native species and ecosystems. Its potential reproductive rate is the highest of any ungulate, but data on reproductive rates of feral pigs are limited. We studied reproduction of feral pigs in two regions of southern Texas: the Gulf Coast Prairies and the western South Texas Plains. Pregnancy rates of adults (>21 months) ranged from 78% during winter (December–February) in the Gulf Coast Prairie to 6% in summer (June–August) in the western study area. Fetal litter sizes in adults tended to be greater (P = 0.11) than those of yearlings. Fecundity ranged from 1.1 female young/year for juvenile females to 4.5 female young/year in adult females. Sex ratio of fetuses (n = 298) was male-biased (P < 0.05) when data from both study areas were combined. Two seasonal peaks of births were observed (January–March and June–July). Fecundity of pigs in southern Texas was more than four times higher than native ungulates, raising serious questions about dynamics of the ungulate community in this region.