Skip to story
ELI5 Yahaaa

Four layers and a good idea

How Do Penguins Stay Warm in the Snow?

An emperor penguin stands through months of the coldest weather on Earth, in the dark, without eating.

Packed featherstrap a layer ofstill airFat underneatha thick blanketthat does notmoveWarm blood insidekept well awayfrom the feet
Warmth is not made once. It is stopped from leaving, four times over.

  1. Step 1 of 5

    The feathers trap air, not heat.

    A smooth, tight coat Still air trappedbetween the shafts

    Penguin feathers are short, stiff and packed tighter than any other bird's. What they hold is a layer of still air against the skin, and still air is one of the best blockers of heat there is.

  2. Step 2 of 5

    Underneath is a blanket of fat.

    Feathers alone Good, but wind can findgapsFat as well A layer nothing getsthrough

    Below the skin sits a thick layer of fat. It works the same way a coat does — it is simply hard for warmth to travel through — and it doubles as the food store for the months without eating.

  3. Step 3 of 5

    The feet are kept deliberately cold.

    Warm blood headingdown Cold blood comingback upThe heat crosses over and turns round

    Bare feet on ice should bleed heat away. So the warm blood going down runs right alongside the cold blood coming back, and hands its heat over before it ever reaches the toes.

  4. Step 4 of 5

    They huddle, and they take turns.

    Cold birds on the outside edge The huddleshufflesinward They reach the warm middle Warmed birdsmove back out

    Thousands of emperor penguins pack together so tightly the middle gets genuinely hot. The huddle shuffles constantly, so the birds on the freezing outside edge slowly work their way in.

  5. Step 5 of 5

    The wings gave up flying for swimming.

    A flying bird Light hollow bones,broad wingsA penguin Heavy bones, stiffflippers

    A penguin's wings are short, flat and solid — useless in air, superb in water. It trades the sky for being able to chase fish at speed, which is where all its food is anyway.

    A male emperor penguin balances the egg on his feet under a fold of skin for about two months of winter dark, and does not eat once in all that time.

The short version

Penguins survive the cold with trapped air, a fat layer, cold feet on purpose, and a huddle that keeps rotating.

Try it yourself

Put one bare hand and one gloved hand outside on a cold day. The glove makes no heat — it just holds still air, exactly like penguin feathers.

Topics

Next tiny story