'Feral Swine Bomb'? Find Out Why Wild Pigs Are Becoming a Problem Everyone Needs to Worry About

As wild pig populations explode, mitigation efforts in the United States and Canada are coordinating to find the best methods to curb the feral swine.

According to the Animal and Plant Health Inspection Service (an agency within the U.S. Department of Agriculture that's responsible for, among other things, managing the damage caused by feral swine), wild pigs have spread to 35 states, with a population over six million. They tear up crops, attack livestock and destroy local habitats, causing more than a billion dollars in estimated damage in the U.S. annually.

Canada has also made efforts to control its flourishing swine population. Research from the University of Saskachewan suggests the range of wild pig populations is expanding by about 35,000 square miles a year. At that rate, Saskatchewan will soon have more pigs than people.

But feral pigs have not yet spread into Montana, the state across the border from Saskatchewan. Undark Magazine, looked at mitigation initatives on both sides of the border, and what it might mean for states where feral pigs are spreading unchecked.

A boar near the border between Mexico and the United States on January 16, 2019 in Candelaria, Texas. Photo by Joe Raedle/Getty Images

"I've heard it referred to as a feral swine bomb," Dale Nolte, manager of the APHIS National Feral Swine Damage Management Program, told Undark. "They multiply so rapidly. To go from a thousand to two thousand, it's not a big deal. But if you've got a million, it doesn't take long to get to four, then eight million."

Feral swine are the wild descendants of domestic pigs, which are of the same species as wild boar breeds. When bred in the wild, feral pigs have tusks that would otherwise be removed by farmers when they're young. Feral swine develop coarse fur and thick hides. Birthing litters of 10 or more piglets, wild pigs have spread rapidly in Florida, California and Texas, the latter of which has a population of approximately 1.5 million feral swine.

Montana has so far prevented their spread, with efforts from the Montana Department of Livestock bolstered by 2015 legislation against owning or transporting feral swine. That law included a ban on hunting wild pigs in order to curtail several incidents of residents importing feral hogs from Texas to shoot.

In November, Montana state agencies and the USDA hosted the Feral Swine Summit in Billings to coordinate ongoing efforts to keep feral swine out of the state. The summit was also used to launch the public "Squeal on Pigs" campaign, which included a 24-hour hotline for wild pig sightings.

Montana's strict efforts have served as a model for other agencies, including in the Canadian province of Ontario, where the Ministry of Natural Resources and Forestry has adopted similar public-facing initiatives to aid in the tracking of wild hog populations.

Increased coordination, such as through Canada's newly inaugurated national steering committee on feral swine, has helped propagate some unorthodox lessons. One is the counterintuitive ineffectiveness of recreational hunting, which has been encouraged in states like Texas and California. When hunted, groups of feral pigs—known as sounders—take drastic steps to avoid being killed. Hunted pigs will radically increase their range, sometimes traveling more than 100 miles, while switching to a nocturnal lifestyle to avoid pursuit.

Unless the whole sounder is killed quickly, hunting can cause swine population chaos, rapidly increasing their spread. Rather than recreational hunters, state authorities have had better luck with killing whole sounders from the air. Thus, hunting bans may be a key component of state-level efforts.

"Shooting can be an effective control measure when only a few individual feral swine are present in an area," the USDA's Wildlife Services site advises. "If larger groups are observed, shooting a few individuals of the group can disrupt the social organization and cause them to disperse even further across the landscape, thereby increasing the potential for damage. It is also very difficult, if not impossible, to shoot all feral swine in a group at one time. Ground shooting is labor intensive and is unlikely to have the desired relief from damage."

In response to the swine bomb, 2014 appropriations established a national management program for feral swine, which will work to "eventually reduce the range and size of feral swine populations in the United States."

Counties in the United States with a wild pig population. USDA

Update 9/29/20: This article was updated to cite Undark Magazine as the source of the feral swine report.