Signs say Manitoba’s wild pigs aren’t headed for a population boom, says Wayne Lees, co-ordinator for Squeal on Pigs Manitoba.
“We’ve always heard that, you know, these pigs are going to explode in population,” Lees said. “Our field experience didn’t really support that, so we wanted to start challenging some of these assumptions.”
WHY IT MATTERS: A study from Squeal on Pigs Manitoba appears to show a slower population growth of wild pigs in Manitoba than originally expected.
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Lees spoke at Manitoba Pork’s annual general meeting in Winnipeg on April 10. Wild pigs are an invasive species in Manitoba where they cause environmental damage and can be a vector for disease.
Lees said his team recorded the proportion of different age groups in groups of pigs they trapped as a sort of “census.” They found that 47 per cent of trapped wild pigs were mature animals, 35 per cent were juveniles and 18 per cent were weanlings.
“I compared pigs to people, which isn’t a great comparison,” said Lees. “I wanted to look at the shapes of these populations.”
Lees showed a graph of age-sex demographics with age groups stacked—oldest on the top, youngest on the bottom. The graphic formed a rough inverted pyramid with the smallest population on the bottom (weanlings), and mature pigs slightly outnumbering juveniles.
Lees compared this to similar charts showing populations of countries with growing and shrinking populations. His chart most closely resembled countries with slow growth or population decline.
“So to me, it’s suggesting that we’re not in a population explosion. We don’t have hordes and hordes of young pigs… yes it will increase, but it’s not going to lead to millions and millions of pigs.”
Why not? A few factors are in play, Lees said. Wild pigs tend to have small litters of four to six piglets. They don’t believe the hogs have more than one litter per year, and they likely require a year to mature to breeding age. Their population will also be limited by feed ability, and Manitoba’s harsh winters tend to kill piglets born in winter.
“In a cold climate, our situation is very, very different than what you see in wild pigs in a warm climate. So we cannot compare our situation to the U.S. where they have millions of pigs in some states,” Lees said.
“It’s not going to happen here.”
Lees said they also had more success in removing wild pigs in 2024 due to greater access to populations in the hot spot area of Spruce Woods Provincial Park.
