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Invasive Species: Feral Swine in Ohio
Invasive Species: Feral Swine in Ohio

About Feral Swine

Feral swine (Sus scrofa) are a combination of Eurasian wild boar and escaped or un-kept domestic swine. Common names for this species include feral hog, swine, or pig, Eurasian boar, Russian wild boar, and razorback. Introduced to the United States in 1539, they now inhabit at least 38 states and 3 U.S. territories. Feral swine cause significant damage each year to agricultural crops and property, as well as natural resources. Farmers and landowners can contact Wildlife Services (WS), a branch of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service for assistance to address feral swine damage on their property.

Feral Swine Identification & Distribution

Feral swine can vary greatly in appearance. Piglets with strong Eurasian influence display distinctive striping form nose to tail, which disappears as they mature. The size of mature adults can vary greatly depending on the ancestral influence. In Ohio, adults range in size from 125–200 pounds. Larger individuals do occur, but in Ohio they rarely exceed 350 pounds.

Feral swine in an Ohio forest.

Feral swine tracks. Feral swine tracks look similar to white-tailed deer tracks but have more rounded toes and the dew claws are wider than the toes.

Feral swine mud rubs on trees. Feral swine rub on trees to remove external parasites and leave behind scent.

Identifying and reporting feral swine (usda.gov)

Breeding Habits

Male feral swine are typically solitary, while females tend to live in groups called “sounders.” Sounders include adult breeding females, offspring that are weaned but not of breeding age, and piglets.

Feral swine may reach sexual maturity as early as 6 months of age and can breed year-round. Under ideal conditions, feral swine can produce up to 2 litters per year in Ohio. Litter size can also vary greatly depending on the origin. Domestic breeds have the ability to produce much larger litters, upwards of 10 piglets, while those of Eurasian lineage produce much smaller litters, averaging 4–6 piglets. 

Distribution

The greatest concentration of verified populations can be found in the unglaciated region of southeastern Ohio. Currently, known breeding populations of feral swine have been confirmed in Adams, Athens, Champaign, Gallia, Hocking, Jackson, Lawrence, Scioto, and Vinton counties. 

Feral pig sightings can be reported by using the ODNR Division of Wildlife Species Sighting Report or by contacting USDA/APHIS Wildlife Services at 1-866-4USDA-WS. 

Damage & Disease

Feral swine cause significant damage to agricultural crops and property, as well as natural resources each year. Ecological and economic losses from feral swine damage in the U.S are estimated to be $1.5 billion annually, when combined with control costs. With the expanding feral swine distribution, this figure may be increasing significantly.

Farmers and landowners can contact USDA/APHIS- Wildlife Services for assistance at 1-866-4USDA-WS to address feral swine damage on their property.

Feral swine dame to a corn field.

Crops

In Ohio, corn and soybeans tend to be the most sought after agricultural food source, but damage to other resources such as orchards, yards, hayfields, pastures, and timber have been reported. It is estimated that feral swine contribute to $800 million in crop damage in the U.S. each year. This does not include the damage feral swine cause to agricultural equipment (i.e. fences, irrigation ditches, water supply). 

Corn damage from feral swine in Ohio fields.

Rooting

Feral swine are often referred to as “living rototillers” due to their destructive digging in search of roots, larva, tubers, eggs, and invertebrates. Rooting can range from a depth of 2 inches to 2 feet (sometimes as deep as 3 feet), causing significant damage to plants and soil integrity.

Extensive rooting from feral swine in Ohio.

Water Quality

In the summer months, feral swine seek out wet areas to roll in the mud or “wallow.” These wallows range in size from small mud puddles to churned slurries exceeding 300 square feet, which severely damage downstream water quality through silt deposition and bacterial contamination.

Feral swine wallows.

Erosion

Whether by rooting or wallowing, disturbed soil from feral swine activity is subject to extensive erosion. The resulting poor-quality soil is often damaged so much that it can only be colonized by invasive plant species. Trees that have had the soil eroded away are left with exposed root systems, as a result of rooting. This makes trees susceptible to blowdown, diseases, and death.

Rooting damage in an Ohio forest.

Predation

Feral swine can prey directly on the nests, eggs, and young of native ground nesting birds and reptiles, including threatened or endangered species. Game birds such as wild turkeys, ruffed grouse, and bobwhite quail can also be impacted. Feral swine have been reported to either opportunistically depredate ground nests or seek them out. 

Feral swine nest depredation is highly variable depending on location and availability of resources. Research suggests removal of feral swine may increase wild turkey recruitment. Stopping the expansion of feral swine is important to protect ground-nesting birds. 

Feral swine have even been documented consuming deer fawns, and actively preying on small mammals, frogs, lizards, and snakes. Feral swine also predate on domestic livestock. While most predation events are undocumented, many reports are for losses of sheep and goats.

Competition

Feral swine compete with native wildlife species for valuable resources, like food, water, and shelter. Acorns that would normally be cached by squirrels, or preferred by white-tailed deer and other wildlife, are consumed at an alarming rate by feral swine. Feral swine will consume seed heads of plants, which negatively impacts seed eating birds such as wild turkey and bobwhite quail.

Impacts to native wildlife (usda.gov) 

Disease

Feral swine can carry at least 30 prominent viral and bacterial diseases and nearly 40 parasites that can impact people, pets, livestock and wildlife. Feral swine are highly social and can travel long distances, posing a concern for disease spread. In Ohio, 2 diseases of great concern are swine brucellosis and pseudorabies, which are lethal infections for both domestic animals and wildlife.

More Information:

Feral Swine Control in Ohio

Disease Surveillance

WS conducts feral swine disease surveillance activities throughout the United States. In 2009, Wildlife Services began collecting biological samples from trapped and hunter-harvested feral swine in Ohio. In 2014, a national initiative was implemented to remove and sample greater numbers of feral swine to better understand the disease threats and damage this invasive species poses to native wildlife, domestic livestock, pets, and humans. 

Control & Elimination

Elimination efforts have been very successful on small, emergent populations in Ohio. In 2014, Ohio elimination efforts increased with the creation of the USDA APHIS National Feral Swine Damage Management program. Efforts expanded from focusing on emergent cases to reducing feral swine populations in areas where they were established. Current elimination efforts continue to combat both counties with emerging or established breeding populations.

Based on GPS collar data, adult feral swine have home range sizes between 3–8 miles in diameter in Ohio. These large home ranges make eradication efforts complex, thus involving extensive collaboration. The elimination of feral swine in Ohio can only be achieved with the cooperation from wildlife managers, agricultural producers, landowners, and sportsmen and women.

Feral Swine Hunting

Hunting usually has little effect on reducing feral swine populations, however Ohio sportsmen are encouraged to report any feral swine they encounter to limit the expansion of swine populations. Feral swine are primarily nocturnal, spending their days resting in dense vegetation or wallowing in mud holes, and their nights foraging. These nuisance animals may be legally harvested year-round by anyone with a valid Ohio hunting license or by landowners on their own property. During the deer gun and statewide muzzleloader seasons, a valid Ohio deer permit is required to harvest feral swine and sportsman should use only firearms legal for the season.

Feral swine, as with any wild game, can be consumed. However, because of potential diseases and parasites it is recommended to use proper field dressing techniques and thoroughly cook the meat to 165°F to kill pathogens and parasites.

For more information or to request assistance please contact USDA/APHIS Wildlife Services at 1-866-4USDA-WS.

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