Feral Swine in Pennsylvania

Posted: July 7, 2014

Feral swine are starting to make their presence known in the forests of Pennsylvania.

By Dr. Matthew Lovallo, Wildlife Biologist, Pennsylvania Game Commission

Feral swine are a non-native, recently introduced, invasive species in Pennsylvania. Any member of the Family Suidae roaming freely upon public or private land is considered feral swine. In appearance, feral swine vary greatly; they are descendants of domestic pigs, Eurasian wild boars, and European and Asian hogs that have escaped or been intentionally released into the wild. They may weigh more than 400 pounds and are very prolific, producing litters of eight to twelve young per year.

Potential impacts of feral swine include environmental damage, predation of and competition with native wildlife, and transmission of disease. Environmental damage caused by these animals includes erosion from the displacement of soil and native plant root structures, consumption and destruction of crops, and predation of livestock (lambs, kid goats, and calves) and ground nesting birds. Damage to wildlife habitat includes: destruction of native vegetation and consumption of foods eaten by native wildlife. Feral swine are omnivorous; but, mast, when available, makes up a large part of their diet. In areas where feral swine are found, their consumption of acorns and other mast reduces the amount left to feed deer, turkey, and other native species.

Feral swine are known to carry eighteen viral diseases, ten of which can infect people, and ten bacterial diseases, all of which cause disease in humans. Swine Brucellosis is a potentially debilitating human disease, and pseudorabies is a disease with significant potential economic importance to Pennsylvania’s swine industry. Feral swine are reservoirs for numerous parasites that can affect people, pets, livestock and wildlife. People usually contract ailments carried by feral swine through contact with affected blood, tissues or aerosol droplets, or by consuming undercooked meat from infected animals. It is also possible for these diseases to be contracted through exposure to other animals originally infected by feral swine. Hunters are advised to take safety precautions when dressing wild/feral swine. Pseudorabies not only affects swine, but is fatal to deer, cattle, sheep, goats, cats, dogs, raccoons, skunks, opossums, and small rodents. Both brucellosis and pseudorabies can be detected through blood tests, but there is no effective treatment for either disease. Disease symptoms range widely, from flu-like ailments to fever, weight loss, organ failure, and death.

In Pennsylvania, the areas of most concern are counties with evidence of reproduction (e.g., Bradford, Bedford and Fulton counties), as well as all counties which contain swine shooting operations. Fenced swine or wild boar shooting operations are a known and significant source of current feral swine populations in Pennsylvania. Because of their distribution throughout the state, feral swine can show up in unexpected areas and habitats. If uncontrolled, the prolific nature of this species and abundance of available food in some areas can result in rapid population growth. Continued monitoring of the known populations, especially those with breeding evidence, is crucial.

Pennsylvania Department of Agriculture (PDA) regulates domestic animals, which by definition are dogs, cats, equine animals, bovine animals, sheep, goat, and porcine animals; this includes animals maintained in captivity, according to PA Domestic Animal Act. In this sense PDA does regulate both domestic and feral swine imports, but enforcement is difficult to achieve.

In Pennsylvania, it is illegal to release domestic animals into the wild and the Pennsylvania Game Commission (PGC) has passed regulations making it illegal to release feral swine onto State Game Lands. Currently the legal taking of feral swine is governed solely by a PGC Executive Order which allows a landowner to shoot feral swine because of the threat imposed to the property; there are no regulations or statutes governing the killing of escaped or released feral swine, except in defense of property. A recent Supreme Court decision extends this responsibility of management of feral swine once they are in the wild to the PGC, leaving for some future decision at the Superior Court level the responsibility for their regulation when they are contained by a fence.

Many states with feral swine problems have created an open season for feral swine with no season or bag limit restrictions to help control the population. The PGC does not promote swine hunting on a recreational basis, and has therefore not created regulations to set seasons or bag limits for swine. While hunting may reduce feral swine populations at a local scale, hunting activities often disperse swine into other areas making them difficult to locate and control. If you encounter feral swine or observe damage from feral swine, please report your observations to the nearest PGC region office.