The penguin is the only bird that can swim but cannot fly

Penguins are unique in the bird world. They are the only non-flying bird that can swim. Lots of birds, such as the duck and the seagull, swim as a secondary means of transportation to flying. They land on ponds and lakes to rest and cool down, but they fly to really get around. Penguins do not have the luxury of an option. Poorly build to move quickly on land, penguins travel quickly through the water when they need to move from place to place.