Knuckle-walking is a way some land animals move. Knuckle-walking animals curl fingers or front toes like a fist and touch the ground using the bony part of the front foot, the knuckle. Gorillas, chimpanzees, anteaters and platypuses knuckle-walk. In general, animals knuckle walk if their hands or front paws have special shapes for doing something very different from walking. Apes use their hands to hold food and use tools, so they have fingers. They curl up their fingers when they knuckle-walk. Anteaters use their front paws to dig for ants, so they curl up their digging claws when they knuckle-walk. Platypuses use their front paws to swim, so they curl up their webbed toes when they knuckle-walk.