12 Emperors of the Ice-Low

EMPERORS OF THE ICE FOCUS Question How do emperor penguins survive in a cold environment?

A Cold Climate Emperor penguins spend their entire lives in the cold. They live in Antarctica. It is the coldest place on Earth. During the coldest months, emperor penguins may experience temperatures as low as -40°C (-40°F). The wind can blow at 144 kilometers per hour (89 mph), making it even harder to stay warm. Luckily, these penguins have two types of adaptations to help them survive in these frigid conditions. Their bodies are well suited to the cold on land as well as in the icy water, where they spend much of their lives. These birds also behave in ways that keep them as warm as possible.

Size and Shape Warm-blooded animals stay warm by keeping their body heat inside. Animals lose heat through the outside, or surface, of their body. Larger animals have a larger surface area. So you might think they lose heat faster. But they also have a larger volume—the amount of space their body takes up. Their surface area is not that big compared to their large volume. This feature helps them keep heat inside their body. Emperor penguins are the largest penguin species As a result they have a low surface-area-to- volume ratio (RAY-she-oh) compared to smaller penguins. This physical adaptation helps emperor penguins survive in very cold conditions.

Look at the egret on this page. It is about the same height as an emperor penguin. But this bird does not have a large volume. It has a large surface area compared to the small volume of its body. It loses heat easily, so it could not survive in Antarctica. Size isn't the only way emperor penguins combat the cold. Their oval body shape helps, too. They don't have a long neck, long legs, or big ears and feet. These parts would add to their surface area. In cold weather, they even hold their flippers close to their body to avoid losing heat. SURFACE AREA AND VOLUME OF CUBES Length of each side (inches) 2 4 6 8 Surface area (square inches) 24 96 216 384 Volume (cubic inches) 8 64 216 512 Ratio of surface area to volume 3.0 1.5 1.0 0.75

Recycled Body Heat Penguins do lose some heat through their flippers and feet. Because these body parts stick out from the rest of their body, the blood in the flippers and feet gets cold very quickly. Emperor penguins have a special system that warms up the cold blood before it enters the rest of the body (see diagram). For example, a penguin's heart pumps warm blood through vessels to the base of the feet (step 1). There other vessels carry cold blood from the feet. The vessels with warm blood are close by. They transfer heat to the vessels carrying cold blood (step 2). As a result, the cold blood from the feet warms up before it flows back into the body (step 3). This heat exchange keeps the penguin warmer.

Outer Layers Emperor penguins also have other physical adaptations that help them stay warm. They have four layers of feathers that overlap tightly, like the scales of a fish. These layers trap heat, even when the fierce winter wind is blowing. But the feathers don't work very well when they get wet. To stay warm while they swim, these penguins have a layer of fat beneath their feathery skin. It's as if they have a waterproof blanket wrapped around them at all times. They can chase fish or avoid predators without worrying about getting too cold. Safety! When it's cold outside. put on several layers. Wear a sweater underneath your coat. That layer will trap extra body heat and keep you warm—just like a penguin!