The Guardian wrote on Monday that wild boar and domestic pig hybrids that have wreaked havoc on Canada’s ecology are now threatening to infiltrate the northern United States. In contrast to other wild pigs, the new species, which can weigh up to 661 pounds, can withstand Canada’s severe winters due to its size.

In addition to their insatiable appetite for native vegetation and animals, pigs pose a concern of spreading disease, which, according to National Geographic, could one day be transmitted to humans. Canadian researchers assert that the super pigs are “very intelligent.” The head of the University of Saskatchewan’s wild pig research project, Ryan Brook, told The Guardian: “They’re highly elusive, and when there’s any pressure on them, especially if people start hunting them, they become almost entirely nocturnal and extremely elusive – hiding in dense forest cover and disappearing into wetlands, making them extremely difficult to locate.”