Near Melfort, Saskatchewan — As the sun sets on the Canadian Prairies, the search begins for one of North America's most destructive animals, a fast-growing population of wild hogs that biologists call "super pigs."

Dr. Ryan Brook, a professor in the University of Saskatchewan's College of Agriculture and Resources, has been tracking them for years. He says they're in the search area for sure.

"No question," Brook told CBS News. "And like, lots of them, not just two, three, there's a lot of pigs out there. It's kind of mildly alarming just how many pigs there are around us right now."

These super pigs have American border states on guard. Experts say they pose a multibillion-dollar threat to the U.S. economy if they ever cross from Canada into the U.S.

Brook, one of Canada's leading authorities on super pigs, calls them an "ecological trainwreck." They're crossbreeds — wild boars deliberately bred with domestic pigs. They're big, smart and prolific breeders. And their population is now spreading out of control.

"I think there's two challenges in Canada," Brook explains on why they have become so difficult to eradicate. "One is their biology makes them very, very hard to get rid of. They reproduce faster than you can shoot them."

They will eat anything to survive, according to Brook. They tear up land and reproduce quickly, with devastating consequences to ranchers and farmers.

For Saskatchewan farmers fed up with the damage, Alain Guillet is the man they call. He catches and kills nearly five super pigs a week.

"They've eaten that's of value off of it, so he's lost all this," Guillet said as he showed CBS News farmland which was ravaged by the super pigs.

"As these populations get bigger and bigger, we're going to see more crop damage," Brook explains. "We're gonna see potential disease spread. These pigs can spread disease to humans, to pets, to wildlife, and to livestock."

Americans have reason to worry. Wild pigs already cause around $2.5 billion in damage to U.S. crops every year, according to the U.S. Department of Agriculture. And they can be aggressive toward humans. A woman in Texas was killed by wild pigs in 2019.

Maggie Nutter, a fourth-generation rancher near Sweetgrass, Montana, keeps a watchful eye out for trespassers. Her ranch is right on the Canadian border.

"So here's the border fence in between us and Canada, just an old barbed-wire fence that I repair in the summer," Nutter shows CBS News.

"You look at all the damage...the billions of dollars of damage that those pigs do down south, and the damage that they're doing up in Canada," Nutter adds. "We can't afford them…It already costs, you know, so much for farm equipment. So much for hay, so much for diesel, we can't afford pigs."

Montana has launched a "Squeal on Pigs" campaign, urging anyone who has seen feral swine to alert officials.

Brook believes it is not if the super pigs spill over the border, but when.

"Well, this is what I've been warning for now into 15 years," Brook said. "And warning anybody who would listen that this is coming."