They do exist

After decades of hurricanes and oil spills, Louisiana faces a new threat - hordes of monstrous 20 pound swamp rats. Known as "nutria", these invasive South American rodents breed faster than bounty hunters can "control" them. With their orange teeth and voracious appetite they are eating up the coastal wetlands that protects Thomas and his town of Delacroix Island from hurricanes, but the people who have lived here for generations will not give up without a fight.