FOCUS Book
Emperors
of the Ice
Put your knowledge of penguin adaptations to practical
use. Design a way to keep a cup of water from freezing
inside a freezer. Start with two identical cups. Fill them
with the same amount of water at the same temperature.
Leave one cup alone.
Treat the other cup as if it were a penguin. Design
adaptations for it to handle the cold in its environment
(a freezer). Discuss your plans with classmates and
change your design if need be. Once you are ready, put
both cups next to each other in the freezer at the same
time. Check back after fifteen minutes, thirty minutes,
and one hour. How did the water in the two cups
compare each time you observed them? How could you
protect your “penguin cup” from the cold even better?
Beyond the Book
Visit a store to compare and evaluate clothes
that are designed to keep people warm in
cold weather.
A Cold Climate
Emperors
of the Ice
antarctica
Emperor penguins spend their
entire lives in the cold. They
live in Antarctica. It is the
coldest place on Earth.
Emperor penguins live on the
ice and in the water around
During the coldest months,
Antarctica (shaded areas).
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.
FOCUS Question
How do emperor penguins survive
in a cold environment?
Structure and Function
Photo Credits:
Front cover: © Vladimir Seliverstov/Dreamstime.com; page 2: © Staphy/Dreamstime.com; page 3 (left):
© Louise Heusinkveld/Alamy; page 3 (center left): © Sergey Korotkov/Dreamstime.com; pages 3 (center right,
right), 4 (left), 7 (bottom): © Jan Martin Will/Dreamstime.com; page 4 (right): © David Steele/123RF; page 6:
© Bernard Breton/Dreamstime.com; page 7 (top): © Naturbild/Science Faction/SuperStock; page 8 (left):
© Stefan Christmann/Corbis; page 8 (right): © Vladimir Seliverstov/123RF; page 9: © Graham Robertson/
Auscape/The Image Works
Illustration Credits:
Page 5: Signe Nordin/© Learning A–Z
Emperors of the Ice
© Learning A–Z
Written by Joe Levit
All rights reserved.
www.sciencea-z.com
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Size and Shape
SURFACE AREA AND
VOLUME OF CUBES
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.
chinstrap
penguin
king penguin
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
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.
emperor penguin
Emperor penguins are larger than any other penguin species.
Adaptations • Emperors of the Ice
2
As a cube gets larger, its surface area and volume get larger.
But the ratio of surface area to volume gets smaller.
Emperor penguins are the largest penguin species.
As a result, they have a low surface-area-tovolume ratio (RAY-she-oh) compared
to smaller penguins. This physical
adaptation helps emperor
penguins survive in very
cold conditions.
little blue
penguin
Length of each side (inches)
3
4
emperor
penguin
great
egret
Recycled Body Heat
Outer Layers
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 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.
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.
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
When it’s cold outside, put
getting too cold.
on several layers. Wear a
sweater underneath your
coat. That layer will trap extra
body heat and keep you
warm—just like a penguin!
Counter-current heat exchange in penguins
Heat exchange warms up cold
blood from the feet before it
enters the rest of the body.
warm blood
from the body
warm blood
to the body
Adaptations • Emperors of the Ice
1
foot
2 heat transfer
3
foot
Emperor penguin feathers are
small and packed together tightly.
5
6
Other Heat Savers
Caring for Young
Emperor penguins also have behavioral adaptations
that help keep them warm. For example, they bask
in the sun. They seem to wear fancy suits, or tuxedos,
but they aren’t dressed for a party! The dark feathers
on their back absorb sunlight, turning it into heat.
Like all birds, emperor penguins lay eggs. How do they
protect the eggs and the babies inside from the bitter
cold? After the female lays an egg, she quickly balances
it on her feet. The egg cannot stay on the frozen ground
for very long.
Do you tiptoe to keep your feet off a cold floor?
Penguins do something similar. They rock back on
their heels to keep their feet off the ice. They lean
against stiff tail feathers.
Since the tail feathers don’t
have blood vessels, the
tripod pose (pictured here)
An emperor penguin leans
is one way to stay toasty.
Soon after laying an egg, the female goes fishing for
a few months. But first, she carefully transfers the egg
to the male. He props the egg on top of his feet to keep
it off the ice. Then he covers the egg from above with
a special layer of feathered skin called a brood pouch.
Once the egg hatches, the pouch will keep the baby
penguin warm.
back on its tail feathers to
keep its feet warm.
An emperor penguin
basking in the warm sun
Adaptations • Emperors of the Ice
A male emperor tucks an egg
in under his brood pouch.
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8
After hatching, the baby
emperor penguin stays warm
under its father’s brood pouch.
Huddle Up!
Male emperor penguins wait two months for the eggs
to hatch. During that time, they don’t eat anything.
They also endure subzero cold and driving wind. A
single penguin would die under these brutal conditions.
Luckily, they have each other!
Write your answers on separate paper. Use details from
the text as evidence.
1 Why is surface area important to an animal that
lives in a very cold climate?
2 How do layers help emperor penguins stay warm
in the water?
Emperor penguins huddle together in enormous groups.
This behavior helps keep the whole group warm. But
howling winds still chill the penguins on the outside of
the group. So the penguins take turns standing on the
outside of the group. Later, they move inside and warm
up in the middle of the group. Talk about teamwork!
3 Why do emperor penguins stand in a tripod stance?
4 How does a male emperor penguin keep
an egg warm?
5 Which strategy used by penguins to stay warm
could also be used by a group of chilly kittens?
With all these special adaptations, emperor penguins
survive and even thrive in the coldest place on Earth!
FOCUS Question
To stay warm, male emperor penguins huddle
together in groups of up to 9,000 individuals!
Adaptations • Emperors of the Ice
How do emperor penguins survive in a cold
environment? Write down five adaptations
that help emperor penguins stay warm.
Then identify each one as either a
physical or behavioral adaptation.
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