What makes a penguin a penguin?

You can easily pick a penguin out of a crowd of people, due to its black and white "tuxedo" color, but it's hard to pick a penguin out of a crowd of penguins because all penguins of a single species look very similar. Compared with other birds, the 17 species of penguins are relatively easy to identify because their heads have distinguishing characteristics. With many birds, the variations existing between the sexes and juveniles makes a species difficult to identify without knowing many patterns. With penguins, features on their heads are distinctive and there are few differences between males and females. The babies appear fluffier than their parents until their adult feathers grow in.

All penguins do not look the same. Some penguins are larger than others and even have yellow feathers decorating their heads. There are 17 different species of penguins that differ in their size, appearance, where they live, and their behavior.

Penguins cannot fly, but in the water, their streamlined bodies and powerful flippers make them strong and graceful swimmers. Penguins swim, but they are not fish. They are birds because they have feathers, lay eggs, and are warm-blooded.

Penguins don't just like snow and ice, in fact, many like it warm and sunny. Penguins live in the Southern hemisphere in places ranging from the cold Antarctic continent, where it can drop to minus 60° Celsius (-76° Fahrenheit), to the Galapagos Islands on the equator where temperatures can rise to 40° Celsius (104° Fahrenheit). Penguins are adapted to their environment so that they never suffer from heat stroke or frostbite.

Penguins look similar to birds like auks and puffins that swim and dive to obtain their food, but don't be fooled. Auks and puffins can fly and penguins cannot. In order for birds to dive in the water, they must have short, small wings and a heavy body. Small wings cannot lift a heavy body off the ground however, so birds like auks and puffins must be light if they want to fly. All penguins weigh more than 1 kilogram, and that is part of the reason why you will never see a penguin flying overhead.