Polar bear: Hey, moose! Why can't penguins fly?
Moose: I have no idea.
Polar bear: Because they don't have enough money to buy plane tickets!
Moose: That's cold, man. Really, really cold.
Okay, so that's an old joke, but we still like it! And it made us WONDER…why can't penguins fly? After all, they are birds, aren't they?
Yes, penguins are aquatic, flightless birds that live in the Southern Hemisphere--especially Antarctica. Unlike the wings of other birds, penguins' wings are more like flippers that make them particularly suited for life in the water.
In fact, penguins are so suited for an aquatic life that their agile swimming looks quite similar to a bird flying through the air. Their smooth feathers trap air, which makes them more buoyant in the water and protects them from the cold water.
Penguins spend about half their time in the water and half their time on land. When they're on land, their flippers and their tails help them keep their balance and walk upright. If they want to move quickly, though, they often slide on their bellies in a movement called tobogganing.
Scientists believe penguins' inability to fly stems from the fact that they likely had no predators where they lived long ago. Because penguins lived near water and had to rely upon the oceans for food, they adapted over time to become more aquatic, exchanging true wings for flippers.
As they exist today, it's easy to see why penguins can't fly. Their flippers, adapted for life in the water, simply cannot generate enough lift to get their chunky bodies into the sky. This is especially true for the largest species of penguin, the Emperor Penguin. Emperor Penguins stand over three feet tall and can weigh 75 pounds or more.