Wildlife
Wild pigs have been wreaking havoc as they spread across Canada. Is their expansion inevitable, or can we put the brakes on this “ecological trainwreck?”
When Ramona Maraj took on the role of ecologist at Elk Island National Park, Alta., in 2018, wild pig capture was not part of the job. Yet five years later, in March 2023, she found herself fixing a GPS collar around the thick neck of a sedated 136-kilogram (300-pound) boar. Seeing a wild pig in real life is like “watching a unicorn pop out of a bush,” says Maraj. “They have a mythical look to them.”
The tusks on this large male extended several inches from its dark snout towards its face, culminating in knife-sharp points. “When you see them, you understand how they do so much damage,” she explains. The pigs use their tusks for defending themselves, fighting, and digging up earth to uncover food. Combined with the push power of their leathery, rigid snouts, they can uproot meadows and cropland as effectively as a rototiller. Strong males like this one have been known to lift and roll heavy logs to get at insects crawling beneath.
Since collaring (and sterilizing) the boar, Maraj and her colleagues have been following his movements to learn where he goes, how he interacts with other animals and where he finds other pigs. Already, the data shows this boar is spending a lot of time in the park. This is unwelcome news.
Along with their tendency to rip up the countryside, wild pigs are potential carriers of a plethora of diseases including tuberculosis and brucellosis. An outbreak of these diseases in Elk Island’s wood and plains bison populations would be a blow to their conservation across North America, as the park provides the seed stock for most bison reintroductions.
With their wild pig program, Maraj and her team join colleagues across Canada in a war to eliminate boar from the landscape. This version of pulling pork is a complicated endeavour with a lot at stake. Some doubt that ridding the country of the pigs is feasible when, over the past four decades, the wily swine have been sighted over an area of a million square kilometers. How did we get here?
Canadian wild pigs (a.k.a. wild swine, wild boar or feral hogs) are the descendants of Eurasian wild boar, domestic pigs and hybrids of the two. Most were brought to Canada in the 1980s to support a federal livestock diversification program designed to aid farmers during a national downturn in agricultural markets. The boars were subsequently bred with domestic pigs, creating a highly winter-adapted eating machine that could pump out a lot of piglets — about six to 16 each year over two litters. Then, like a virus in a dystopian novel, these hogdinis busted free. As the wild boar meat market crashed in 2001, some farmers simply cut their losses and opened their gates.
Canada’s wild pigs often travel in packs called sounders, and come equipped with thick brown fur covering barrel-shaped, 70 to 100 kilogram (154 to 220 pounds) bodies. The biggest boar that University of Saskatchewan researcher Ryan Brook ever handled in his 14 years studying them was a whopping 290 kilograms (638 pounds). “Their large bodies help them survive the cold,” he says — more girth to hold heat, and less surface area to lose it. The furry pigs easily survive the harshest -40 C prairie winters. They avoid biting cold by staying toasty together in quinzee-like snow dens.
As voracious omnivores, they have rooted their way across Canada, ferreting slugs and bugs from soil and poaching eggs from nests. They slurp up frogs and ducklings from wetlands, wolf down mice and clear meadows right down to plant roots. In parts of Manitoba, they specialize on acorns, an important food source for birds, squirrels, and deer. “Pigs seem to be savants at scanning the landscape and finding the best quality food available,” says Brook. “They’ll even scavenge road-killed white-tailed deer.” They eat live deer, too. In February, the Saskatchewan Wildlife Federation released a photo of a boar running across a field with a fawn in its mouth.
While wild pigs adapt to almost any environment, they thrive in agricultural areas where they pilfer grain and other crops. It starts early in the season when the fields are first planted. “After seeding, pigs will actually get their nose in the ground, push along, and hoover all the seeds like vacuums,” says Brook. Later in the year, pigs trample and root up crops like canola, wheat and barley. But one crop is favoured.
“Corn is king for pigs,” says Brook. It provides them with excellent nutrition and cover for concealment. Hiding in tall corn or the cover of nearby trees, wild pigs can make sting missions to harass livestock, steal their food and sometimes snatch newborn lambs, goats, and calves.
In the U.S., where more than six million pigs are mowing their way through the southern states, agricultural losses are estimated at over U.S. $2.5 billion. Alberta and Saskatchewan have programs that compensate farmers for crop losses to wild pigs, though relatively few farmers have made claims. Exact amounts were not available for Alberta, but Saskatchewan paid out roughly $9,700 for three claims in 2022 (claims for 2023 are still being calculated). Not a large sum compared with the approximately $25.8 million they paid out in compensation for other big game wildlife species damage in the same period, writes Tessa Krofchek in an email on behalf of the Saskatchewan Crop Insurance Corporation. Saskatchewan first paid compensation for wild boar crop damage in 2010, while Alberta began its compensation program in 2022.
There are less pigs and therefore less crop damage in Canada to be sure, but the lack of claims might also be influenced by the claim process, says Alberta wild boar program specialist Hannah McKenzie. In Alberta, farmers are required to take steps to mitigate future damage, allow government officials and trappers to access to their property, as well as restrict hunting access. Still, McKenzie says, “We know from anecdotal reports that farmers are experiencing damage in areas of heavy wild boar infestation.”
Via winter smarts, torpedo-style birthing, and treating their surroundings like a fast-food joint, feral swine have expanded beyond their native range in Eurasia and North Africa to all continents except Antarctica. Now one of the world’s most destructive invasive species, they have contributed to the decline of hundreds of at-risk animals and plants, including skinks, tortoises, frogs, and orchids. “When a sounder of pigs moves into an area, everything else moves out, especially anything that nests on the ground,” says Darrell Crabbe, executive director of the Saskatchewan Wildlife Federation. More than 40 years after their introduction to Canada, the pigs are now well-established in the Prairies — and making forays into Quebec, B.C. and Ontario.
As part of their 2021 “Strategy to Address the Threat of Invasive Wild Pigs,” Ontario has declared them an invasive species, and phased out boar farms (facilities with the potential to harbour pig escape artists). Right now, “we don’t know of any self-sustaining populations in Ontario,” says Tore Buchanan, Wildlife Research Coordinator with the Ontario Ministry of Natural Resources and Forestry.
Meanwhile, the northern creep of wild pig sightings has the attention of Rob Gau, manager of biodiversity and conservation with the Northwest Territories department of Environment and Natural Resources. The risk is close enough that Gau and colleagues have been conducting aerial monitoring flights since 2020 to scour the land for traces of the swine. “We have boreal caribou, wood bison, and moose populations — all incredibly important for our communities and traditional harvesting,” he explains. “Wild pigs are something we can’t have in the Northwest Territories.”
One big concern about the brazen boar is their potential to spread disease. They are potential hosts of at least 30 diseases and 40 types of parasites. The virus pseudorabies, for example, is fatal to cats and dogs, and causes stillbirths and miscarriages in feral and domestic swine. Wild pigs can pass viral foot and mouth disease to deer, sheep, goats, bison, and cattle. Infected livestock must be euthanized. In 2001, an outbreak of foot and mouth in the United Kingdom cost U.S. $9 to 13 billion. Pigs can host several diseases harmful to people, such as salmonella, hepatitis, and pathogenic E. coli.
But perhaps the biggest driver of recent action on wild pigs in Canada comes from the potential risk of African Swine Fever (ASF), a highly contagious viral disease with no cure and a nearly 100 per cent death rate in pigs. Though the disease has not yet been reported in Canada, “in the past five to ten years we’ve seen rapid spread of ASF on multiple fronts,” says Mathieu Pruvot who, with his graduate students, is studying disease transmission by wild pigs at the University of Calgary, Alberta.
Spread is progressing rapidly from eastern to western Europe, he says, and in the years 2018 and 2019 it spread through China and southeast Asia. In 2021, the virus popped up in the Dominican Republic — the closest yet to North America. “That has really ramped up the action on the U.S. and Canada side,” says Pruvot.
Wild pigs can transmit ASF from one farm to another. As the disease spreads, costs multiply. An infection in Canada would put a $7 billion CAD pork industry at risk, says Stephen Heckbert, executive director of the Canada Pork Council. Heaped on the manure pile of other economic, ecological, and agricultural losses associated with invasive swine, it underlines why eliminating the pigs is the goal of every current wild pig program in Canada.
Getting rid of the pigs is not as easy as announcing open season on wild boar. In fact, eradication of wild pigs is difficult in areas where they are valued for hunting and food, write the authors of the IUCN’s 100 of the World’s Worst Invasive Species report. In other parts of the world where boar are heavily hunted, females have young earlier and more frequently, and have increased levels of reproductive hormones.
Though government agencies and many other organizations discourage it, sport hunting of wild pigs continues in the prairie provinces. And rather than help remove pigs, it’s thought to break sounders into smaller groups that then require more eradication effort. Hunting teaches the pigs to be wary of people, and pushes them further out into the landscape, says Pruvot. They learn to avoid moving during the day. Consequently, people stop seeing them, and mistakenly think the hunting is helping, he explains.
While some hunters are interested in bagging wild bacon, others are concerned. Darrell Crabbe from the Saskatchewan Wildlife Federation, a group originally formed by the local hunting community, says “the vast majority of hunters recognize the negative effect an established pig population would have on everything else we cherish.”
“Working with clever wild swine means constantly adapting.”
The front line of Canada’s eradication efforts is being led by various groups at the provincial or territorial level, some with federal funding. Each program model is different, but since 2022 they share the common goal of asking the public to report pig sightings or “Squeal on Pigs” to help trappers find the wily swine.
Alberta was an early responder to the wild pig problem, perhaps given their tough stance on other invasives like rats, and the relative success of their rat control program. Since 2003 the province has trialled several initiatives — including bounty programs — with varying success. In 2015, following the science, they steered the program toward monitoring and trapping techniques known to be highly efficient in removing pigs. The Alberta Wild Boar Control Program partnered with the Alberta Invasive Species Council and Alberta Pork on wild pig detection and eradication and are developing a systematic monitoring program using trail cameras to confirm pig locations and ultimately track populations to detect whether pig removal efforts are making a dent. Numbers are important.
Since 2018, Alberta has destroyed 367 pigs. If that is out of 450 pigs, that’s pretty successful, says Hannah McKenzie. “But if that’s out of 5,000 pigs, then we’re not doing so well.” Like most jurisdictions in Canada, the actual number of pigs is largely unknown, though their distribution across the landscape — where they’ve been sighted — has been tracked in various ways over time.
In the meantime, McKenzie helps trappers locate pigs with her dog, Suess, trained to sniff out boar poop through the province’s conservation K9 group. Trappers also use drones to scout pigs from the air — anything to get the upper hand (or hoof). Pigs are smart, fast learners, and every group is different, muses McKenzie. “Trappers spend a lot of time trying to get inside the mind of the wild boar.”
One of those trappers is Devon Baete, field manager of eradication operations for Manitoba Squeal on Pigs. He’s been climbing the learning curve since a group of young, 14- to 18-kilogram (30- to 40-pound) pigs “launched themselves quite aggressively” at him, luckily from behind the bars of the first corral trap he set as a local wildlife club volunteer in 2018.
Working with clever wild swine means constantly adapting, says Baete. Originally, his program adopted tracking and removal techniques from U.S. states like Texas where more than 2.5 million pigs run wild in a very different environment to Manitoba. It didn’t take long before Baete redesigned the Texas-style traps so they didn’t freeze into the ground.
Manitoba pigs behave differently than Texas pigs, and maybe even Alberta and Saskatchewan pigs, too. They seem to travel in small groups rather than large sounders, he says.
Sometimes, individual pigs develop a unique habit, like the boar Baete recently tracked about 50 kilometres west of Brandon, Man., that liked to root around in wolf willow. “We’ve had to change baits because of that — not all pigs like the same things.”
Baete’s team learn all they can through the 90 cellular trail cameras deployed across the southern part of the province. In 2023, the absence of pigs in spring camera photos from key areas suggests the team’s efforts are making a dent in those populations, he says. Wayne Lees, a veterinarian and coordinator of Manitoba Squeal on Pigs, says that of the 283 pigs publicly reported to their program in 2022 and 2023, the team caught and destroyed 249. Since January 1st of this year, the team has removed an additional 55 pigs using 30 traps, and regular deployment of thermal drones, to help spot pigs hiding under the cover of corn and spruce trees.
Bringing together data from provincial programs and researchers like Pruvot, Brooks and others is one of the goals of Canada’s new invasive wild pig strategy for 2022 to 2032. The strategy, still in the consultation phase, was penned by Canada’s National Invasive Pig Leadership Group, a long list of government and non-government organizations.
The federal response has taken some time, perhaps because, as it says in the strategy, the wild pig issue does not belong to any single entity at the national level given its entanglement in a web of multiple jurisdictions with varying levels of resources and capacity. Multiple partners need to be at the table because the wild pig issue is a “One Health” issue, meaning it links environmental, human, and domestic animal health, says Gabby Nichols, executive director of the Canadian Council of Invasive Species. The plan outlines a 10-year strategy to eradicate invasive pigs, a feat the authors point out will require “funding commitments from stakeholders and partners.”
Meanwhile, the boar war rages on. Can Canadian wild pigs be eradicated? Some say yes. “There is no quick and easy fix, but it is my belief that with perseverance and hard work, we can be successful in the long run,” writes Lees in the 2023 Manitoba Squeal on Pigs program update.
Yet Pruvot says that’s a difficult question. There’s been a lot of work to understand how widespread they are, but we don’t have good estimates of actual numbers, he explains. Having real numbers would help land managers better understand the resources required to eliminate them. Still, without knowing that baseline, he says, “I think we can safely say that eradication would require massively ramped up control efforts.”
Brook is less hopeful. “The window for nationwide eradication has passed,” he says. He suggests focusing on preventing spread to provinces and territories that are currently pig-free and helping provinces like British Columbia battle back their relatively small populations. In the Prairies, he recommends establishing priority areas for eradication, such as those near big domestic pig farms, or national parks like Elk Island where feral hogs could have outsized effects.
Nationwide agreement on whether wild pig eradication is possible will likely happen when pigs fly. For now, the secretive swine pillage their way across the prairie provinces, wreaking havoc on ecosystems as they go — and are poised to cause economic devastation in the domestic pig industry. Says Brook, “you introduce these pigs anywhere on Earth, and this is what they do.”
This story is from the July/August 2024 Issue
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