What protects a penguin from the cold?

Think of a snowy day, when the wind nips your cheeks and your fingers start to tingle. You pull on a puffy coat, a hat and warm mittens. Far away in Antarctica, many penguins live on the ice and swim in freezing sea water.

A penguin has no coat to zip up and no mittens to pull on. It waddles across the snow and dives into icy water, and its body still stays warm. So what protects a penguin from the cold?

Let's look closely at a penguin's body. Tiny, stiff feathers cover it from head to tail, packed tightly together and overlapping like tiles on a roof. When the icy wind blows, it slides over the feathers and cannot reach the skin.

The penguin squeezes oil from a little spot near its tail and spreads it over its feathers with its beak. The oil makes the feathers waterproof, so sea water rolls off them like rain off a raincoat. That way the penguin's skin stays dry, even when it swims.

At the bottom of each outer feather grows down, which means tiny fluffy feathers that hug the skin. The down holds a thin layer of warm air right against the penguin's body, just like the puffy stuffing in your winter coat. Can you guess what a penguin has under its skin to keep warm too?

Beneath the feathers and down, a penguin has something more under its skin. It is a thick layer of blubber, which means soft body fat that wraps all the way around the penguin. You can picture blubber as a squishy blanket inside the body that holds the penguin's own warmth in.

Blubber helps most when the penguin dives. Icy water pulls warmth from a body much faster than cold air does. The thick blubber keeps the heat tucked inside while the penguin swims and chases fish.

Down and blubber. A penguin stays warm because its tight, oily feathers keep the cold wind and water out, its soft down holds warm air against its skin, and its thick blubber holds its body heat in.

Sleep warm and snug tonight, just like a penguin tucked inside its feathers.