Feral hogs (Sus scrofa) recently have been introduced to Illinois. They are important to resource managers because of their potentially negative ecological and economic impacts. We assessed the distribution, habitat use, and body morphology of feral hogs in Illinois. We confirmed the occurrence of feral hogs in Fulton, Hardin, Johnson, Lawrence, Massac, Pope, Randolph, and Union counties. Forest and croplands probably are the most important habitats for feral hogs in Illinois. We found free-ranging hogs in Illinois included four previously described morphotypes with distinguishable physical/cranial characteristics: domestic hogs, feral hogs, hybrids, and Eurasian wild hogs. However, 32.6% of individuals were outside of these previously described morphotypes. External morphology and pelage usually were consistent with cranial analysis in determining morphotypes. Whole and dressed body weight regression indicated that dressed weight was about 85% of whole weight. We suggest that the goal of resource managers in Illinois should be to contain or eradicate existing feral hog populations. This should be addressed while populations are small and relatively isolated. If current practices continue, feral hogs have the potential to eventually increase in density and distribution throughout much of Illinois.
McCann, Blake, Davie, Daniel K. and Feldhamer, George A. "Distribution, Habitat Use, and Morphotypes of Feral Hogs (Sus scrofa) in Illinois." (Jan 2003).