There was an article this morning on AOL that talked about a baby penguin born without feathers and abandoned by his family. He didn't have the proper nutrition to allow for feather growth. I always assumed that feathers were important to a penguins survival, but wasn't certain on what they actually did. I started looking into what feather did for penguins and learned something interesting about how penguins use there feathers to get out of the water.
Emperor Penguins are flightless birds but can often be seen leaping out of the water so high that they look like they are flying. This is leaping is necessary because the shape of penguins (torpedo), there instability on land, and the limited use of their wings outside of water make it impossible for a penguin to lift themselves over the ice back on to the land. However what was determined was that the speed at which the penguins exited the water was much to high to be accounted for by only buoyancy factors. They exit the water at about 5.3 m/s. So physicist attempted to determine how it was that they are able to exit the water so quickly and what they used other than buoyancy.
What was determined was that the air bubble stream that is seen behind them prior to exiting the water is actually air released from there feathers. The penguins clean and fluff there feathers prior to entering the water allowing for lots of air to be stored. Then when wanting to exit the water they depress there feathers. The air expelled increases there speed and decreases there drag. This causes them to have enough speed to propel out of the water and fly through the air onto the ice. This uses the physic properties of fluid dynamics, air lubrication, and buoyancy.
On a side note the veterinarians at the zoo were able to fix the nutrition problems of the penguins allowing him to grow feathers and return to his family.