If you look at a Penguins' flippers closely, they look like wings. Penguins even look like they are flying when they are actually swimming.
It makes me wonder if Penguins evolved into aquatic birds from lang birds.
They are quite flexible in the water. This is hard to believe after watching them walk so awkwardly. They have a layer of air that helps them stay warm and float.
Penguins coloring is designed to be like camouflage. When predators are looking up in the water, their white bellies look like the water and when predators look down into the water, their black backs blend into the earth.