MINNEAPOLIS– An exploding population of hard-to-eradicate “super pigs” in Canada threatens to spread south of the border, and northern states like Minnesota, North Dakota and Montana are taking steps to stop the invasion.
In Canada, wild pigs roaming Alberta, Saskatchewan and Manitoba are a new threat. They are often crossbreeds that combine the survival skills of wild Eurasian boars with the size and high fertility of domestic pigs, creating a “super pig” that is spiraling out of control.
Ryan Brook, a professor at the University of Saskatchewan and one of Canada’s leading authorities on the problem, calls feral pigs “the most invasive animal on the planet” and “an ecological train wreck.”
Pigs are not native to North America. Although they have roamed parts of the continent for centuries, Canada’s problem only dates to the 1980s, when it encouraged farmers to raise wild boars, Brook said. The market collapsed after its 2001 peak and some frustrated farmers simply cut their fences, freeing the animals.
It turned out that the pigs could survive the Canadian winters very well. They are smart, adaptable and furry and will eat anything, including crops and wildlife. They tear up land as they search for insects and crops. They can spread devastating diseases to pig farms, such as African swine fever. And they reproduce quickly. A sow can have six piglets per litter and raise two litters per year.
That means 65% or more of the feral pig population could be killed each year and will continue to increase, Brook said. Hunting only makes the problem worse, he said. The success rate for hunters is only about 2% to 3% and several states have banned hunting because it makes the pigs more wary and nocturnal – harder to track and eradicate.
Feral pigs already cause about $2.5 billion in damage to U.S. crops every year, mostly in southern states like Texas. And they can be aggressive towards people. In 2019, a woman in Texas was killed by wild boars.
Eradicating feral pigs is no longer possible in Manitoba and Saskatchewan, Brook said. But the situation is not hopeless everywhere and a few US states have eliminated them. The key, he said, is having a detection system that finds them early and quickly and then responds quickly.
Brook and his colleagues have documented 62,000 sightings of feral pigs in Canada. Their aerial survey has spotted them on both sides of the Canada-North Dakota border. They also recorded a sighting in Manitoba, within 28 kilometers of Minnesota.
“No one should be surprised if pigs cross the border if they haven’t already,” Brook said. “The question is: what is being done about it?”
Brook said Montana has been the most serious about keeping feral hogs out. It banned the breeding and transportation of feral pigs within the state.
“The only way forward is you have to be very aggressive and use every tool in the toolbox,” Brook said.
These can be large ground traps with names like ‘BoarBuster’ or net cannons fired from helicopters. Some states and provinces are embracing crowdsourced “Squeal on Pigs” tracking programs. Scientists have also studied toxins such as sodium nitrite, but these risk harming other species.
Minnesota is among the states trying to prevent the hogs from gaining traction. The state Department of Natural Resources is expected to release a report in February identifying gaps in the management plan and recommending new prevention steps. Meanwhile, the U.S. Department of Agriculture is using planes and drones to beef up surveillance along the northern border.
Minnesota was declared an exterminated state after USDA Wildlife Services shot and killed a group of pigs in 2016 that strayed from a farm and became feral in the far northwest corner of the state — but not before they began reproducing and wiping out a wildlife refuge. Gary Nohrenberg, director of Minnesota Wildlife Services, said that as far as he knows, no truly wild hogs have come to his state yet.
According to the USDA, feral pigs have been reported in at least 35 states. The agency estimates the pig population in those states is about 6 million.
Since the launch of the National Feral Swine Management Program in 2014, the USDA has provided funding to 33 states, said Mike Marlow, assistant program director. He said their goal is to eradicate feral pigs where the population is low or increasing, and to limit damage where they are already established, such as Texas and the southeastern states.
The program has had success in some states with small populations, such as Vermont, New York, Pennsylvania, New Hampshire, Wisconsin and Washington, he said. The animals are occasionally spotted and quickly killed in North Dakota.
“I think we are making great progress toward success,” Marlow said. “But eradication will not happen in the near future.”
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