Granted, they’re not as big or scary as real pigs, but these cuddly critters are fast becoming a major nuisance on the Hawaiian island of Oahu. Authorities speculate that most of the island’s guinea pigs are descended from fugitive pets (or perhaps from just one pregnant runaway). Either way, these furry ferals are devouring residents’ shrubbery and ornamental plants at an alarming rate, and taking a significant toll on native plants and crops as well. Nor is the problem likely to go away anytime soon. Each female guinea pig typically gives birth twice a year to up to four pups per litter.