Penguins are flightless birds belonging to the 'spheniscidae' family, which mostly breed in the Southern Hemisphere. Though they are usually associated with Antarctica, some species are found near the Equator as well. It is believed that the name 'penguin' originated from the Welsh word 'Pen Gwyn', meaning white head. They are hefty birds with a heavy and robust skeletal system. It's their heavy bone structure that hinders their ability to fly.
Like all birds, penguins also have wings. These are known as flippers. The shape of their flippers resembles that of an airplane's wings. They are hard and heavy, and are covered with tiny feathers that are stiff but not waterproof. The flippers primarily help the penguins to swim swiftly, but their use is not restricted to swimming alone.
Flippers as a Defensive Weapon
Penguins use their flippers as weapons to defend themselves from their predators. At the same time, they are also used as weapons during fights. Penguins are aggressive when they guard their nests. They use their flippers to defend themselves and their young ones. The strike of a flipper is painful enough to cause the predators to retreat.
Other Uses of Flippers
Unlike the other parts of their body, these fin-like structures are not heavily insulated. Therefore, on a hot day, the penguins spread them out. This causes the heat to flow away from their body and helps them cool down.
Remember that penguins are aquatic birds and hence, they spend a considerable part of their day in the water. They come over to the land only for breeding and molting. That explains why their flippers are more suitable for swimming than flying. The penguins can swim at a speed of 8km/hr.
To sum up, flippers are modified wings that help these aquatic birds to swim, defend themselves from their enemies, and cool down on a hot summer day.