A University of Saskatchewan study finds that the species is expanding its range by nine percent a year in Canada
The first-ever comprehensive mapping study of wild pig distribution in Canada has been undertaken by researchers in the College of Agriculture and Bioresources at the University of Saskatchewan.
The survey showed that the invasive species is expanding its range by nine percent a year and has spread out to cover more than 777,783 sq. kilometres.
Native to Eurasia and parts of North Africa, wild boars were imported from Europe as part of an agricultural initiative to diversify Canadian agriculture in the 1980s.
But some pigs escaped or were intentionally released. They rapidly established themselves in Manitoba, Saskatchewan and Alberta with 58 percent of the national population occurring in Saskatchewan. By 2017, the wild pig population had expanded and established local populations in British Columbia, Ontario and Quebec. Only the four Atlantic provinces have no confirmed sightings.
In the United States, feral pigs have been well established for a few hundred years and they, too, have rapidly expanded their range from 17 to 38 states in the last 30 years.
Wild pigs cause extensive soil erosion, disruption of ecosystems, degradation of water sources and riparian areas, and destruction of crops.
“Wild pigs are ecological train wrecks,” wrote PhD student Ruth Aschim in the report published in Scientific Reports in May.
“They are prolific breeders making them an extremely successful invasive species.”
And they are stubborn, resourceful survivalists.
“The source animals for wild pigs in Canada are from a broad range of climate, including Siberia, so they are well adapted with their large body size (in some cases more than 226 kilograms) and heavy fur coat allowing them to thrive in the long, cold, snowy winters of the Canadian Prairies,” said Ryan Brook, associate professor and lead researcher for the Canadian Wild Pig Project.
“Agriculture plays a very big role in that they feed on extremely high-quality agricultural crops through summer and fall and during winter from haystacks, swath grazing, bale grazing, spill crop, grain bags, and baiting/feeding sites.”
They are also a nuisance for cattle. While Brook is not aware of predation on livestock, he knows of cattle producers who have had their animals harassed and scared by wild pigs coming into watering and feeding areas and pushing cows away.
Brook said that wild pigs make “pig-loos” in marshes, staying under the snow and benefiting from the insulation of the snow layer. However, they are active throughout the year, regularly foraging for food even when it is cold and the snow is deep. He said climate change may benefit wild pigs with longer summer growing seasons and reduced temperatures but may also have negative effects due to predicted weather extremes such as melting events or rain mid-winter, making accessing food under the snow and ice difficult.
Managing wild pigs is a challenge and each province is responsible for their own population control.
“Each has taken a different approach, and some have been far more proactive than others,” said Brook. “Manitoba is by far the most proactive and declared the province a control zone to shoot any wild pigs. Saskatchewan has contracted individuals to trap, snare and shoot wild pigs in high density areas. Alberta has undertaken trapping and a bounty for many years.”
Unfortunately, hunting and bounties are not seriously impacting the pigs’ numbers. Predation from wolves, bears and cougars in some regions may help but Brook points out that wild pigs are mostly found on farmland where predators may be shot on sight. Aschim, who led the science-based mapping research, and Brook completed the study, which is expected to provide new information to help develop additional provincial and national strategies for wild pig control.