RESEARCH ▶▶▶
Controlling feral pigs in the US and Canada
Feral pigs are a growing problem in North America. While a national control strategy is now in place in the US with pilot projects underway, Canada has nothing similar – and Canada’s pork industry may pay the price.
BY TREENA HEIN, CORRESPONDENT W
hile African Swine Fever (ASF) is not yet found in North or South America, even one case could spread quickly across the US and Cana- da if it enters the enormous – and rapidly
growing – population of feral pigs. Control of the population in both countries has proven fruitless so far. A few decades ago, feral pigs were brought to Canada from Europe, where they are usually called wild boar. In Canada, they mated with domestic pigs. Some of the hybrids either escaped or were freed, and since then their descendants have spread from British Columbia to Quebec.
Nailing down the feral pig population Since around 2011 Dr Ryan Brook, an associate professor at the University of Saskatchewan, has led efforts in the Canadi- an Wild Pig Research Project to nail down the population. He and PhD student Ruth Aschim have spent recent years map- ping distribution using trail cameras, GPS data gathered through collars attached to pigs they caught, and interviews with landowners (see Figure 1). Sharp tusks help wild pigs fend off predators such as wolves – and in any case, it would take a very determined effort by a pack of wolves or a bear to take down one of these massive animals, which often live in groups and have individual weights that can exceed 270kg (about 600 pounds).
6 ▶PIG PROGRESS | Volume 36, No. 6, 2020
Captured: A feral pig is kept under control in order to fit the animal with a GPS collar.
Large wild pig body size and survival There is a reason for the pigs’ size. “A large body size is particu- larly important for surviving extreme cold,” says Dr Brook. Win- ters in parts of Canada can have extremely cold temperatures. During the winter of 2018/2019, at least 12 low temperature records were broken in Saskatchewan. Perhaps due to the harsh winters, some Canadian hybrid wild pigs are considering a move south. It was reported in 2019 that US officials are mon- itoring wild pig movements at the border between Saskatche- wan/Alberta in Canada and the state of Montana. But sharp tusks and winter hardiness aside, the key to the amazing spread of the hybrid wild pigs in Canada – about 90,000km2
per year, says Dr Brook – is their astounding repro-
ductive rate. Canadian wild pigs have an average of six off- spring per litter and sometimes more than one litter a year. They become sexually mature by about six months of age.
Control difficult of wild pig populations According to Dr Brook, wild pig populations have been wiped out in several US states using a multi-pronged strategy. He
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