Yes, rockchucks and ground squirrels both also whistle to signal approaching danger. So, DUUHHH, that's why Westerners call them whistle pigs, too... Further, the rockchuck (Marmota flaviventris) and the groundhog (Marmota monax) are related - both in the marmot family. Even further, the groundhog (also known as woodchucks or whistle pigs) are found from east central Alaska south to northern Idaho and across southern Canada in the west. They are found throughout the eastern United States as far south as central Alabama and Arkansas and as far west as the plains states.