Penguins, like other flightless birds (ostriches and emus) evolved from birds that could fly. About 65 million years ago their ancestors probably flew over the ocean and dove down into the water for food. Like the whales, they were probably looking for where food was more plentiful.

Over millions of years, the penguins developed and evolved to become superb divers, and in the process lost the power of flight. A flying bird has to minimize its weight, so all flying birds have hollow bones. In the process of evolution, the penguins hollow bones became solid and heavy so they could no longer lift themselves out of the water to fly. Their heavier bones made is easier for them to dive down into the water.

Penguins are excellent divers, they can dive to depths of 1000 meters and remain down for up to 20 minutes. While penguins cannot fly in the air, They are so fast underwater that it seems like they fly through the water.