Science & Nature: The ________, A Primitive Pig, Has Tusks That Grow Through Its Snout On Its Upper Jaw And Grow Straight Upward. These Tusks Then Curve Back Toward The Animal's Face And Eyes. If Not Broken Off Occasionally, A Tusk Could Grow In Almost A Complete Circle. This Could End Up Pushing Against The ________'S Head And Into Its Skull, Ultimately Killing It