A Mangalitsa boar, left, and two Russian swine on a farm near McBain, Michigan. The state reported no feral swine sightings 30 years ago but now has up to 3,000 wild hogs. John Flesher / AP

XENIA, Ohio — It isn’t often that the Ohio Department of Natural Resources is involved in cleaning up after a traffic accident. But what happened on busy U.S. Route 35 outside the small town of Xenia last week was anything but ordinary. A semitrailer truck filled with 2,200 feeder piglets en route from South Carolina to slaughter in Indiana met a different fate from originally planned. As the truck approached a sharp bend, the driver lost control, crashing through a guardrail and sending the semi and all its cargo squealing down a steep and heavily wooded ravine. Hundreds of pigs were crushed on impact or so seriously maimed that they had to be euthanized, but about 1,300 piglets survived and escaped. Aided by a posse of area farmers who were hastily mobilized, more than 1,000 piglets were quickly rounded up and taken to a nearby fairground to await their original fate. But several hundred lucky piglets melted into the surrounding thicket. And that has Ohio wildlife biologists very concerned. “The sole reason we got involved was to make sure that all of the piglets are rounded up [so] that they can’t establish a colony,” said Todd Haines, the district manager for the Ohio Department of Natural Resources. It would not be the first time. Feral hogs have been on the increase in the Midwest in recent years. While no national database of feral hog numbers is kept, some states maintain tallies. Michigan had no reported feral swine sightings 30 years ago; as of this year, the Michigan Department of Natural Resources estimates, up to 3,000 wild hogs are spread out over the state’s 83 counties. The Missouri Department of Conservation says few feral hogs existed in the state until the 1990s; now it estimates that 10,000 are prowling the state. Other Midwestern states anecdotally report that their wild hog populations have followed the same trajectory. Ohio keeps no tally of the hog population. “They are very secretive, very difficult to count, but we know they are a growing problem” said Andy Montoney, the director of the U.S. Department of Agriculture’s wildlife services division in Ohio. The fact that Ohio mobilized so many resources to corral the piglets illustrates just how seriously officials view the threat from feral hogs.

‘The sole reason we got involved was to make sure that all of the piglets are rounded up [so] that they can’t establish a colony.’ Todd Haines Ohio Deptartment of Natural Resources

Wild hogs are destructive, and their prolific breeding ensures population growth. Sows can reproduce at as young as 6 months and have two litters a year of four to 10 young. With no natural predators to stop them, the hogs become king of the ecosystem once established. They’ll eat anything in their path, from endangered nesting ground bird eggs to deer fawns. And their impact on agriculture is extremely costly. Hogs can destroy acres of crops in a single day, rooting sometimes as deep as 2 feet down in soft soil and polishing off acres of produce in a night, which is when they are most active. The USDA estimates that feral hogs cause $1.5 billion in annual damage. Feral hogs in the Midwest have two sources: escaped domesticated pigs from farms and Eurasian wild boar that find their way out of hunting preserves. Sometimes the two cross-breed in the wild. Hopes that the colder climate of the Midwest might stop the proliferation of feral pigs seen in the South are unrealistic, said Nate Newman, a state wildlife biologist with the Michigan Department of Natural Resources. “These are Eurasian wild boar, used to the cold climate of Siberia and Europe, so our winters don’t faze them,” he said. Montoney has a full-time staff of three working to eliminate wild hogs from the state. He said 200 wild hogs were removed from Ohio during the past fiscal year. The southeast of Ohio is a feral stronghold, with populations also establishing themselves in the state as far north as Lake Erie. Other Midwestern states like Indiana and Michigan have their own feral swine elimination programs. Though experts believe the piglets from the Xenia crash were unlikely to survive long in the wild, state officials are leaving nothing to chance. “Any hog out there is a concern. These piglets are in the 20-to-30-pound range and about 4 to 6 weeks in age. Obviously they are eating on their own, so there is the potential they could survive,” Haines said.

Probably their best shot at survival would be to make it to the nearby Glen Thompson Reserve, a 50-acre refuge of thick woods, ravines and rivers. This is where Alicia Pell, the national placement coordinator for Farm Sanctuary and a team of volunteers were on standby for much of the week. Farm Sanctuary is a national advocacy group for farm animals and often provides refuge for wayward livestock at its 175-acre spread in upstate New York. Two days after the crash, she and her team were waiting and hoping that they would be able to rescue some animals. “It’s a delicate situation,” Pell said, referring to the politics of who gets rescued animals — a refuge or the original destination. Farm Sanctuary remains hopeful some will be recovered and that the group will be able to take them. A thorough search of the steep ravines and nearby private land 48 to 72 hours after the crash revealed scant pig presence. “We saw no live pigs. In fact, we didn’t see any evidence of any substantial number of pigs. We are guessing if there are any still alive, it is a small number, maybe less than 10,” said Brett Beaty, the wildlife management supervisor with the Ohio Department of Natural Resources. But even if a dozen survived, that is enough to establish a very destructive presence. “A single hog can root up acres over time. I’ve seen a dozen pigs root up 40 acres, so even if there is just one out there, that is a problem,” Montoney said.

A truck carrying some 2,200 piglets overturned in Xenia Township, Ohio, June 8, 2015. Several hundred that escaped have not been found, posing a threat that they will establish a feral colony. Jim Noelker / The Dayton Daily News / AP