Most species of penguins swim together, in either small or large groups, when looking for food. Some penguins spend almost 3/4 of their lives on the water. Some species of penguins, like the Rockhopper and Macaroni, use the porpoising breathing technique while swimming. They swim just below the surface, then leap above the water's surface to take a quick breath. Other penguin species, like the Gentoos, like to swim below the surface of 2 minutes and then take a short breathing break at the surface for 30 seconds. Penguins can swim about 3 to 6 miles per an hour using either of these methods. The fastest swimmers, the Emperor penguins, have an average speed of about 9 miles per an hour.
Penguin Body Adaptions for Swimming
The penguin's body is especially adapted for swimming. For example, penguins will engage the small muscles their feathers to create a tight waterproof layer. These feathers are also coated with a special oil to keep the water out. This feather layer also reduces additional air, so the penguin won't float in the water while swimming or diving. In addition, the penguin's bones are quite heavy, so the penguin will be weighted and stay below the surface. The bones counteract the penguin's blubber, or fat, layer that keeps it warm but also cause the penguin to float.
The wings of a penguin are more suited for swimming than flying. In fact, these small wings look flippers or propellers, but the penguins use these wings to "fly" through the water. These smaller wings beat at a more rapid rate and increased speed. Penguins use their well developed breast and wing muscles to swim through the dense water.
The penguin's blood, specifically its hemoglobin, is specially adapted to circulate additional amounts of oxygen for use during swimming. In additional, a large amount of myoglobin is found in the muscle tissue to store oxygen for breathing underwater.
Penguins also use special swimming postures. They will tuck their heads near their shoulders to keep their body shape compact in the water. Keeping the feet close to the tail also helps the penguin navigate while swimming. When leaping onto land, the penguin uses its webbed feet to help stabilize it during the sudden transition from the water.
Using the Senses While Swimming
Penguins fully use certain senses when swimming. For example, the penguin's vision is optimized for underwater swimming rather than flying through the sky. Their eyes differentiate between shades of blues, purples and greens, the colors of the oceans and the seas. They also have a secondary see-through eyelid to see clearly underwater. Penguins rely mostly on their vision and their superior sense of hearing to hunt for prey and to outmaneuver any predators.