ocr: FLIGHTLESS BIRDS Wings SHOULDER PENGUIN USES its wings Ato "fly" underwater. CURVED BLADE The wings are strong and This shape reduces almost rigid and cannot be friction against folded. Penguins beat their the water wings up and down to move forward and also use them as rudders to steer. Swimming penguins reach a top speed of about 15 mph (24 km/h). When traveling at speed, they alternately swim underwater and burst through the surface to take a breath. This is called porpoising. OVERLAPPING FEATHERS
