Food Habitats and Nutrition
Feral hog food habits have been studied in all ecoregions of Texas mentioned above. These data show some basic similarities in food use between hogs in Texas and those in other regions of North America. Briefly, feral hogs feed on grasses and forbs in the spring, fruits in summer and fall, and roots, tubers, and invertebrates throughout the year (Springer 1977, Wood and Roark 1980, Sweeney and Sweeney 1982, Baber and Coblentz 1987). Composition changes seasonally and with food availability. In the western Rio Grande Plains, grasses, forbs, root/tubers, and corn each composed >14% of stomach contents on an annual basis (Hellgren and Holzem 1992). Cactus fruit and hard mast were 10.4 and 9.0% of the annual diet, respectively. Differences between years were related to changes in precipitation and soil moisture (Everitt and Alaniz 1980).
Fall diets of hogs in Texas were dominated by grapes, acorns (Quercus spp.) and invertebrates in the gulf coast and post oak savannah regions (Springer 1977, Kroll 1986, Yarrow and Kroll 1989); and by roots/tubers, corn, and herbaceous material in the western Rio Grande Plains, where oak trees are less abundant (Everitt and Alaniz 1980, Hellgren and Hozem 1992). Mast composed nearly 25% of the fall diet in 1 of 3 years in the Rio Grande Plains, with acorns and fruits of persimmon (Diospyros texana) and huisache (Acacia farnesiana) being the major species consumed (Hellgren and Holzem 1992). Winter hog diets in Texas were also dominated by herbaceous material (grasses, forbs) and agricultural grains in the Rio Grande Plains (Ellisor 1973, Everitt and Alaniz 1980, Hellgren and Holzem 1992). Springer (1977) reported winter use of primarily acorns and herbaceous material, while Kroll (1986) and Yarrow and Kroll (1989) documented the use of animal matter and forbs.
Animal matter generally was a small (<5%) to moderate (15-25%) but seasonally variable component of hog diets, except in the post oak savannah study (Kroll 1986, Yarrow and Kroll 1989), where animal matter composed >25% of the diet in 4 of 8 study seasons. The post oak savannah data are extremely biased, however. For example, in winter 1983, hog represented 30% of the diet by volume, but only occurred in 1 of 20 stomachs (5% frequency of occurrence). Similarly, armadillo (Dasypus novemcinctus) occurred in only 1 of 4 stomachs (25% frequency) in spring 1983, yet represented 38% of the overall diet. The authors determined seasonal composition of diets based on total gross stomach material examined (Kroll 1986), rather than weighting each stomach equally. Major invertebrate foods of Texan hogs were lepidopteran (Hellgren and Holzem 1992) and march fly (Springer 1977) larvae, and earthworms (Lumbricus spp.; Kroll 1986). Major vertebrate foods consumed were hog, armadillo, white-tailed deer (Odocoileus virginianus; including fawns), and some birds, reptiles, and amphibians.