Chapter 1
A bird at sea
Picture yourself on the ice beside a penguin. It stands tall, then slips into the sea. Its body takes a smooth swimming shape. You will never see it fly, but watch its wings work under water.
Find the parts
A penguin's wings are flat, stiff flippers covered in short feathers. Its webbed feet sit far back on its body. They help it steer in water.
Look beside the head. Adult emperor penguins have yellow patches there. Other kinds of penguins have different marks.
A coat of feathers
Short, overlapping feathers help keep water away from a penguin's skin. Air held among them helps keep the bird warm. Body fat slows heat loss too.
A penguin cleans and arranges its feathers with its bill. This care is called preening. It spreads oil from a gland near the tail.
A place to grow
Emperor penguins breed on sea ice that is attached to the coast. The ice must last while their chicks grow.
A small chick's soft down is not a swimming coat. It needs waterproof feathers before it can live at sea.
Away from the ice
Some penguins live in warm places. Galapagos penguins live on tropical islands. They shelter in cracks and caves in coastal lava rock.
Cold ocean currents help support the fish that Galapagos penguins eat. Warm air above the shore does not mean warm water below it.
Chapter 2
Keeping an egg warm
Could you care for an egg for weeks without stopping for a meal? An emperor penguin father does. In most species, penguin parents take turns warming their eggs. Emperors have a different plan.
An egg on his feet
An emperor penguin father holds the egg on his feet. A warm fold of skin covers it. His mate passed him the egg before leaving to feed at sea.
Keeping an egg warm is called incubation. The father's body warms the egg for many weeks. The egg rests above the ice, not in the snow.
Where does his energy come from?
The emperor father cannot leave his egg to hunt. He lives on fat stored in his body. Going without meals is called fasting.
His fast starts even before he begins warming the egg. So he must save warmth and energy through the winter.
Close together
Male emperor penguins huddle while they warm their eggs in winter. Nearby bodies give shelter and warmth. The huddle helps the fathers save energy.
Field measurements show that a huddle is warmer than the open air. That warmth matters during a long fast.
Different kinds of care
Many penguins build nests. Others shelter their eggs in burrows or caves. Emperor penguins build no nest at all. Feet and a skin fold do the job.
In most species, both parents take turns warming the eggs. When you see a penguin egg, ask which kind of penguin laid it.
Chapter 3
A hungry chick
Imagine you have just hatched on the winter ice. You would need warmth and food. A new emperor chick fits on a parent's feet, under the warm fold of skin.
A parent returns
Penguin parents feed their chicks with food caught at sea. An emperor mother returns around the time of hatching, sometimes before and sometimes after.
Then emperor parents take turns. One keeps the small chick warm while the other finds food.
Bringing food home
A parent carries the meal inside its stomach. It brings the food back up and feeds the chick through its bill.
Emperor penguins catch fish, krill, and squid. Other penguin species eat their own mix of sea animals.
Finding family
An emperor colony has no nests to use as meeting places. Family members find one another by their calls.
As emperor chicks grow, they can gather in groups. Parents usually feed their own chicks, even in a crowd.
Ready for the sea
A chick's fluffy down cannot keep water out. New feathers replace the down as the young bird grows.
Growing up takes different amounts of time in different species. Some young penguins still get meals after their first sea trips.
Chapter 4
Wings under water
Take a deep breath and imagine a dive. A swimming penguin draws its head toward its shoulders. It tucks its feet close to its tail. Now its wings do the work.
Push through water
Penguins use their wings to swim, not to fly in the sky. Strong muscles move the flat flippers through water.
A flipper bends less than a flying bird's wing. Its bones are broad and flat. The feet help steer while the wings push.
Down for a meal
Penguins dive to find food. They breathe air at the surface and hold their breath below it.
Dives vary with the kind of penguin and its food. One deep emperor dive cannot tell us how every penguin hunts.
Air to keep moving
Oxygen is a gas the body uses. Emperor penguins carry it in their breathing system, blood, and muscles.
A penguin cannot pull oxygen from water like a fish with gills. It must come up to breathe.
Meals linked together
Tiny living things in Antarctic waters use sunlight. Krill eat them, and some penguins eat the krill.
Penguins hunt, but they can be hunted too. Leopard seals and killer whales can eat penguins.
Chapter 5
Look a little closer
What colors do you think of when you picture a penguin? Many adult penguins have black backs and white fronts. Little penguins can have blue-toned backs. Some kinds have bright patches near the head.
Two sides to a bird
Adult penguins usually have dark backs and light fronts. This pattern is called countershading. It may help a swimming bird blend in.
Seen from above, a dark back may help a bird blend with darker water. Seen from below, a light front may match brighter water.
Seeing and explaining
We can see a penguin's dark back and light front. Explaining what those colors do takes more work.
The pattern may help with hiding in some views. Researchers question whether hiding explains it in every setting.
Time for new feathers
Feathers wear out. Penguins grow new ones beneath the old ones, pushing the old coat out. This change is called a molt.
Adult emperor penguins stay out of the water while they replace their coat. It is not waterproof during a molt.
Where would you look?
Wild penguins live mostly south of the equator. Many live along Antarctic coasts and on islands near Antarctica.
Polar bears live in the Arctic, in the far north. A wild penguin does not share its home with a polar bear.
A clue from space
Penguin droppings leave brown stains on snow and ice. Scientists look for these stains in satellite images to find emperor colonies.
A stain points to a group, not to one bird. To see change, scientists compare images over time.
Your next question
Choose a picture from this book. Say what you can see. Then ask a question the picture cannot answer.
If you ever visit wild penguins, give them space. Follow the local wildlife rules.
Penguin quiz
Where does an emperor father hold his egg?
Show the answer
On his feet.
How does a winter huddle help emperor fathers?
Show the answer
It saves warmth and energy.
Where does a parent carry food for its chick?
Show the answer
In its stomach.
Which body parts drive a penguin through water?
Show the answer
Its wings.
Why must a diving penguin come up?
Show the answer
To breathe air.
What pattern may help a penguin blend in?
Show the answer
Dark back, light front.
Glossary
- countershading
- A pattern with a dark back and a light front.
- down
- The fluffy feathers that cover a growing chick.
- flipper
- A penguin's flat wing, used for swimming.
- food web
- Feeding links between living things.
- incubation
- Keeping an egg warm while the chick grows inside.
- krill
- Small sea animals that look like shrimp. Some penguins eat them.
- molt
- The change from old feathers to new ones.
- preening
- Caring for feathers with the bill.
How we know
A useful explanation starts with evidence. Ask what was seen, and what still needs a test.