Wild Pigs Threaten Farms Across North America

Farmers in the south have been dealing with wild pigs for decades, but increasing numbers of this invasive species are spreading across the United States and Canada, threatening farmland, ag operations and the environment.

Farmers Hot Line spoke with Aaron Sumrall, PhD, director of outreach, education and research at Pig Brig, about where wild pigs come from, the damage they do and what landowners can do to help mitigate the problem.

Why Pigs Go Wild

Wild pigs, or feral swine, descend from escaped domestic pigs and Eurasian wild boars imported for sport hunting. They’re stocky with coarse hair and tusks, and adults can weigh up to 400 pounds. They are voracious eaters, using their excellent sense of smell to find plants and animals to meet their omnivorous diet. Pigs also have few natural predators and reproduce quickly, so a single pregnant sow or pair can start an infestation.

So can humans.

“In the past, the natural progression of pigs was eight to 18 miles per year due to natural movement,” Sumrall says. “But illegal transportation has become a major issue, putting pigs in places they haven’t been before.”

He explains that people who transport pigs are usually incentivized by hunting and selling pig hunts. It’s illegal to move invasive species including wild pigs across state lines, but that doesn’t stop motivated hunters and those who see dollar signs. And the pigs don’t follow rules, either.

“In every instance where pigs are brought in for financial incentives, they don’t follow a script,” he says. “When released, there’s never sufficient human pressure to keep them in check. There are multiple examples where illegal transportation has brought them in, and in just a few short seasons, they establish themselves. Then, even those who brought them are cursing the fact that they’ve gotten out of hand.”

When that happens, there’s virtually no getting rid of them. “Once pigs are established, it’s almost impossible to get any level of management,” says Sumrall. “We never use the word ‘control.’ Control implies ruling over them, but no one has control once wild pigs are established.”

Assessing the Damage

Wild pigs’ survival drive leads them to devastate the areas where they make themselves at home. They uproot plants and large swaths of agricultural land in pursuit of food, and they can cause serious damage in just a few hours or overnight, eating crops, harming domesticated animals, trampling fields and reducing future yields.

“There are $2.5 billion in direct losses per year from pigs in agriculture, including crop damage, loss and predation on livestock,” says Sumrall.

They also compete for resources with native and farmed species, and they kill ground-nesting birds and small animals. This can upset ecosystems, causing other wildlife to turn to croplands for food and shelter.

As they forage, wild pigs damage and topple fences, letting out livestock and letting in other animals, and they destroy irrigation lines. All of that rooting contributes to erosion, causing soil degradation and loss of topsoil. They also wallow, contaminating ponds, streams and other bodies of water.

Beyond that, wild pigs are known disease vectors, spreading brucellosis, pseudorabies, swine fever and even chronic wasting disease to native species and livestock.

For all of these reasons, wild pigs affect supply and price chains. “Up until 10 or 15 years ago, the popular belief was that pigs were just an agricultural or wildland problem that didn’t impact anyone else,” Sumrall says. “But anyone walking through a store is impacted. Yes, farmers are impacted at the farm level, but when consumers buy commodities off the shelf, prices have some level of influence due to pig damage. There’s no end to the damage and fallout from pigs on the market as a whole.”

And, he adds, it’s only going to get worse as pig populations increase in more locations.

 “When we think about what pig concerns are now and could be due to improper management and the species’ ability to adapt to any given landscape, it’s pretty scary to think where this could go if we don’t get a handle on it.”

No Silver Bullets

One of the biggest barriers to management is the land itself. “Land areas that were once much larger and occupied by a single landowner are now fragmented,” says Sumrall. “One-thousand acres might be divided into multiple tracts, each with its own management strategy or no management strategy at all. All it takes is one or two landowners to do nothing or mismanage their land. When that happens, it creates a sanctuary for these animals.”

Wild pigs are extremely responsive to human pressure and they flourish in the absence of it. They leave areas when they feel unsafe, returning at night or when human activity stops. During daytime or when under pressure, they seek shelter in sanctuary areas with no management strategies in place. These spots become breeding habitats and the population booms even when nearby landowners take steps to reduce wild pig numbers.

“There isn’t a silver bullet for pig management,” Sumrall warns. “What has to happen is adaptive strategy.” He explains that management is possible when farmers and pig management companies adapt their strategies to current conditions and include preventative measures, physical barriers and removal and legal efforts.

The key is customized approaches adapted to each property. “Some properties will share the same fence line, but they’ll all have different approaches and plans,” Sumrall says. “If someone provides you with a definitive plan for your property without seeing it and understanding your local management approach, that’s bad information. We have to teach people how to look for what’s needed and how to incorporate it into their current strategies, whether they’re farmers, ranchers or landowners.”

How to Deal With the Wild Pig Problem

First, educate yourself. “We need people to fully understand the adaptability and biology of the animal and get rid of misinformation,” Sumrall says.

He explains that misinformation can make pigs sound much worse than they are or downplay experts’ very real concerns. Only by understanding the realities of the situation will landowners, legislators and others be able to make the right moves to manage it.

You can be proactive by talking to local officials. Find out what legislators know about wild pigs and whether they’re committed to finding management strategies. “There has to be a concerted effort,” Sumrall says. “One positive development in the last 10 years is that the pig problem has become an issue on the radar of legislators. We saw significant movements with wild pig management in the 2018 Farm Bill. It’s nice to see that farmers and ranchers aren’t fighting this battle alone.”

Sumrall says it’s important to listen to what neighbors are saying. Take rumors of wild pig sightings seriously and actively oppose those who want to import pigs. “If you hear anybody talking about bringing in pigs, heavily discourage it,” he suggests.

If wild pigs aren’t known to be in your area but you spot some, call local wildlife managers immediately. “Report sightings to the wildlife agency,” Sumrall says. “If you see a family group of pigs, don’t shoot or turn dogs loose. You might scatter those animals when there needs to be concerted efforts to remove them. Agencies have the resources to do that. Call your regulatory wildlife agency and tell them where the pigs are.”

If wild pigs are already established in your area and you see them or signs of them on your property, Sumrall’s No. 1 piece of advice is “Do not delay. Anything that puts pressure on the animals so they don’t want to linger in your location will afford you a little more time. If you or others in your area have seen pigs, start active management right away.”  He cautions that any delay in setting up a management plan will allow them to breed and make it that much harder to find a solution.

Overall, every landowner is responsible for combating the problem, and every management must be carefully constructed for its specific location and situation.

“Wild pig management work and challenges are varied and much more complicated than people perceive them to be,” says Sumrall. “Pigs are arguably one of the smartest animals on the planet, and improperly structured management plans can make the issue worse rather than better. They respond quickly to human activities, whether good or bad, and they learn rapidly. This needs to be a focused issue for management plans, and each one needs to be constructed to reach specific goals without further educating an already-smart animal.”