Feral hogs are not cute pigs playing in a barnyard. Wild boars number 9 million and growing quickly — eating and trampling agricultural crops, damaging streams and spreading disease to livestock and people, the University of Delaware said in an announcement.
“Controlling feral hogs is very expensive. For farmers, it’s not just about the risk of what feral hogs can do to their property; it’s also about the costs of spending money to control them,” said Sean Ellis, a postdoctoral researcher with the University of Delaware Center for Experimental & Applied Economics. “Most farmers are small business owners operating on a thin margin of profit. They have to be very smart about directing their resources to the most impactful areas of their business.”
Along with Kent Messer, Ellis is a co-author of new feral hog research published this October in Applied Economic Perspectives & Policy.
Like many other invasive pests, these hogs run amok due to a lack of natural predators to control the population. In the U.S., they cause an estimated $1.5 billion in damage and control costs annually, the university noted. Genetically, feral hogs are a blend of domestic swine and the Eurasian wild boars, taking the strongest characteristics from each — thick fur, a strong sense of smell and superior intelligence — to make a prolific species.
Now, the problem has reached epidemic levels in 35 U.S. states across the Southeast and spreading north, the University of Delaware said. Highly affected states are more vulnerable to transmission of diseases and exotic parasites from these hogs.
Farmers, landowners and public land managers alike are working to combat populations of feral swine, but efforts to stop their spread are only as strong as the weakest link, the researchers said. For example, if one landowner scares the hogs off the property, the feral pigs will move to another farm or public lands.
“There is very little economic research on this issue, but ultimately it’s an economic problem involving human behavior,” Ellis said. “Solving the problem requires coordinated community action, but the members of the community face varying levels of risk: the financial loss from feral hog damage and the opportunity cost of investing limited financial resources into solving this problem instead of elsewhere.”
Controlling the hogs is not as simple as sending out hunting parties. Efforts to trap or shoot the wild hogs are often thwarted because these opportunistic omnivores are clever and adaptable, the university said. Groups of hogs, known as sounders, move across large areas. Once hunted, they learn to hide or lie still when people are present. They also can become exclusively nocturnal and often change or expand their home range.
Feral hog control is also difficult because of the species’ high fertility. A sounders’ size can double in four months. A pregnant sow can reproduce as early as six months of age, typically bearing 4-12 piglets per year.
Additionally, feral hogs are not just staying on rural lands but are making suburban communities their home, especially across the South, the researchers said. For example, they noted that from 2014 to 2018, the National Feral Swine Damage Management Program spent more than $1 million in Pennsylvania to control feral hogs in counties like Lancaster and York.
“Many parts of the country are becoming more suburban. That increases the number of interactions between feral hogs and people,” Ellis said. “Since they carry a lot of diseases and are physically large animals, that is a concern.”
Stopping the spread takes a coordinated community effort, Ellis said, adding that farmers and public land managers must work in concert. Even if all area property owners work together, without a local feral hog control program, the hogs will retreat to safer areas like deep woods or river bottoms, repopulate and come back. Conversely, public land managers in highly affected areas that have feral hog control programs cannot stop these animals without the participation of surrounding landowners, the researchers said.
While new federal funding recently became available for feral hog management through the 2018 farm bill, how best to spend the money is not well understood. This research is designed to help ensure that these funds are used in a manner that effectively addresses the problem.
One of the most effective methods for controlling feral hogs is a remotely operated trap, but these are expensive. For their research, Ellis, Messer and their co-authors at Albany State University and Johns Hopkins University developed a cost-share program to see if they could increase adoption. Landowners could bid in actual auctions around the country for trapping systems that boasted remote monitoring and gate closure features. Included in the price of the trap was a year of cellular service for remote monitoring, as well as delivery, setup and training provided by a Jager Pro contractor.
“Our results show that landowners require substantial financial assistance when implementing control efforts with high upfront costs, such as remotely operated traps,” said Messer, the S. Hallock du Pont professor and director of the Center for Experimental & Applied Economics. “Some landowners may even require a financial incentive to use methods like trapping, as they ultimately cost money to maintain and operate. This research suggests that landowners are reluctant to invest in these traps if they don’t believe that their neighbors will do their part in controlling the hogs.”
Through collaboration of researchers from the University of Delaware, Albany State University, Johns Hopkins University and the Center for Behavioral & Experimental Agri-Environmental Research, the study was funded by the U.S. Department of Agriculture's National Institute of Food & Agriculture.