There are roughly nine million feral swine running rampant across the US. The invasive species already costs the US an estimated $2.5 billion each year in damages and control costs, according to the US Department of Agriculture (USDA). As their numbers continue to rise, the damage will only get worse.

In fact, the wild pig population has expanded from 17 states to at least 39 over the last three decades, The Atlantic reported.

“I’ve heard it referred to as a feral swine bomb,” says Dale Nolte, manager of the National Feral Swine Damage Management Program at the USDA. “They multiply so rapidly. To go from a thousand to two thousand, it’s not a big deal. But if you’ve got a million, it doesn’t take long to get to 4 [million], then 8 million.”