gray fur is heterozygous dominant for mice
grey_squirrel is squirrel. mice has fur grayish_mouse_opossum is mammal. mice has not fur grayish_mouse_opossum is not mammal. eastern_gray_squirrel is not mammal. gray_wolf is not mammal. grey_squirrel is not squirrel. eastern_gray_squirrel is mammal. gray_wolf is mammal.