State goes high tech to control feral swine

wild hog
Ohio hunters are encouraged to harvest any feral swine they encounter to help eliminate this invasive species. The state has open season on the wild hogs, which can be killed 365 days a year with no bag limit. (Ohio Division of Wildlife photo)

For the past six years, federal and state programs to manage feral pigs have enabled drone surveillance, sharpshooters in helicopters and high-tech traps that ensure all suspects are corralled before the gate slams shut. Sometimes, the state-of-the-art technologies seem more suitable for special ops than an ag agency.

The programs also include efforts to educate the public about these four-legged menaces. In the education realm, the methods are definitely low tech: posters, magnets, even a coloring book for children. And the message is simple.

“Feral swine are not good for people, for livestock, for the environment,” said Tyler Genders, who is Ohio’s feral swine coordinator for the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service Wildlife Services. “We need to work with all state and federal agencies to eliminate them.”

Damage management

The USDA and APHIS began the National Feral Swine Damage Management Program in 2014. In addition to and in cooperation with that program, the 2018 Farm Bill authorized the Feral Swine Eradication and Control Pilot Program “to respond to the threat they pose to agriculture, native ecosystems and human and animal health.”

Why all this effort and millions of dollars in expense? For starters, feral pigs cause an estimated $1.5 billion in damage every year. Pigs can’t sweat, so they wallow to cool off. They also root, rub trees, tunnel, make trails and leave tracks with their cloven hooves.

Damage to agriculture includes row crops, nursery and landscaping, forestry and pasture. They have even damaged cultural and historical sites. They pollute and degrade water and ruin local ecosystems.

Their gorging on acorns and tree seeds reduces reforestation and takes food away from native species, displacing them or resulting in their demise. They also prey on deer fawns, turkey nests and other mammals, as well as birds and amphibians, some of which are endangered or threatened species. The pigs’ poop contains the evidence: hair, scales and feathers. One Ohio boar had 15 frogs in its stomach.

Disease carriers

As if that weren’t enough, “feral swine carry 30 different diseases and 37 parasites,” said Genders, who is also a wildlife disease biologist. Those diseases include pseudorabies and swine brucellosis. That brucellosis can kill domestic pigs or cause them to miscarry, and can also be transmitted to humans, he said.

One strain of pseudorabies can cause “mad itch” in dogs, which is fatal. Feral pigs can also transmit diseases to cattle, sheep, goats and other livestock.

First settlers

Feral swine are the descendents of escaped or released pigs. According to USDA/APHIS reports, explorers and the first settlers brought pigs to America in the 1500s as a food source. In the coastal and southern regions, they probably didn’t try to fence them in but let them roam till it was time to harvest, Genders said.

Then in the 1900s, Russian and Eurasian boars were imported for hunting — including to Ohio. There was supposedly a hunting preserve in the state that closed in the 1980s, and the hogs may have escaped or were released by the owner, he said.

Even today, feral pigs are brought up from the South and released for hunting. Which is, of course, illegal.

“We’ve had some weird cases,” Genders said. “Criminals bring in feral pigs for their own gain, charging people to hunt, or in some cases releasing them and then offering to get rid of them at a high cost.”

Ohio history

The pigs’ invasion of Ohio has been fairly recent. An APHIS map from 1982 shows there were some in Kentucky and Indiana counties that border the state, but none had yet been reported in Ohio. By 2016, feral pigs were confirmed in 21 Ohio counties.

“The general public started seeing them in the early 1990s and 2000s, mostly in southern counties like Vinton, Hocking and Athens,” Genders said. “People would report them, we’d put a dot on the map, but there was no verification.”

In Ohio, feral swine resemble the Russian and Eurasian boar, whereas the ones in the South can be light in color, or spotted, looking more like domestic varieties. Perhaps that’s because of the release of hunting hogs, but it could also be a matter of survival in the colder climate. The Ohio hogs have longer, darker, coarser hair, and less fatty, longer bodies than the Southerners, Genders said.

Feral pigs form large groups called sounders. They’re led by an alpha female and include her offspring, plus other sows and their offspring. Boars aren’t included; they venture off and are loners, traveling long distances — mostly at night — to find receptive sows.

Year-round breeders

Like domestic pigs, feral pigs can breed year-round. The gestation period is three months, three weeks and three days, he said. Ohio sows usually have two litters a year, sometimes three, but piglets born in winter don’t have good chances of survival. The offspring are supposed to reach sexual maturity at about six months, “but we’ve seen them trying to mate and even getting pregnant at four months,” Genders said.

Ohio sows usually have three to six piglets; less than in southern states where they can have as many as 12, he said. Still, with early sexual maturity and litters of nearly half a dozen, it’s possible for a sounder to double in size in four months.

“The big question is, what are we doing about it?” Genders said. “In the Ohio wildlife program, we’ve been able to remove close to 900 feral pigs since 2014.”

That may not sound like much compared to, say, 20,000 in a southern state. But, “it’s a very large number for a midwestern state,” he said.

Removal techniques

How were they removed? The five technicians in the feral swine management program have found the most surefire method is that high-tech corral trap.

“A camera sends pictures to our cell phones, and we can send a text to the camera to drop the trap’s gate,” Genders said.

The gates on the old traps could be triggered by anything that hit the mechanism, which could be a deer or a dog. Or, it tripped when not all of the targeted swine were inside.

“If we only trapped two of 10, that caused eight to be trap educated,” he said. “Monitoring a group of pigs and building a trap might take a month, but then we get them all.”

A lot of the monitoring is done by drone, first surveying the damage, then locating the perpetrators. And while trapping is the most successful method for eliminating feral pigs in Ohio, wildlife staff must occasionally resort to other techniques. Sometimes that involves sharpshooters, who are highly trained by the USDA/APHIS Wildlife Services, taking out the sounder from a helicopter. Or, they might use firearms with thermal optics.

While it’s impossible to determine feral swine populations because they move so much, the wildlife services program has succeeded in reducing the number of counties where pigs have been confirmed from the 21 in 2016 to 16 counties last year.

“We were able to remove more than 70 swine in Lorain County and in 2018, the county was declared free of feral swine,” Genders said. “We’ve also confirmed there are no longer pigs in Morgan County or Brown County. A hunting preserve in Trumbull County closed in 2019 and we were able to remove all the remaining pigs to ensure they didn’t become established in the wild.”

People can help by calling 866-4-USDA-WS if they see pigs that seem to be out of place. If they’re determined to be feral, wildlife management staff will launch a high-tech operation to remove them, “safely, effectively and humanely,” Genders said. “And for free.”


Up-to-date agriculture news in your inbox!



We are glad you have chosen to leave a comment. Please keep in mind that comments are moderated according to our comment policy.

Receive emails as this discussion progresses.