Graceful Giants

• Skill: Main Idea and Details

What do you think is the biggest creature that has ever lived? What is or was this creature like? Find out if your answers are correct as you complete the activities in Graceful Giants.

Start by clicking the first activity below.

	1.	Before You Read: The Largest Animal Ever
	2.	"Graceful Giants of the Sea"
		"Graceful Giants of the Sea" Worksheet
	3.	Rate Yourself

Take-Home Activity: Sea Mammals in Aquariums

If you don't already have a copy of this activity, click the link above. Then print out the page or copy the instructions.

Blue Whale

What's the most massive creature that has ever lived on Earth? Is it the 100-ton ultrasaurus? No. Is it the 110-ton Argentinosaurus? Not even close! Although these long-extinct dinosaurs are among the biggest animals ever, the most massive creature of all time still swims in our oceans. Have you guessed which creature this is? It is the blue whale. The heaviest blue whale on record weighed more than 190 tons. (That's 380,000 pounds!) This whale weighed about as much as two ultrasauruses, or 30 African elephants, or 2,600 adult humans! But size is only one of the amazing things about the blue whale and its cetacean relatives.

What do you know about whales? Write what you know in a word web like the one below.

Share your web with some classmates. When you are done with your web, read on to learn some amazing facts about whales.

• Whales are mammals, not fish. Like other mammals, baby whales drink their mothers' milk—and lots of it! Some baby whales have 40 meals a day, drinking a total of 100 gallons of milk.

• With one deep breath, a whale can take in as much air as in thousands of your breaths. Some whales can hold their breath underwater for more than an hour. When whales breathe out through the blowholes on their heads, the air can travel 300 miles per hour.

• Whales make the loudest sounds of any living thing. Some sounds made by the blue whale can be heard underwater more than 500 miles away.

In the next activity, you'll read about one extraordinary kind of whale that wanders the world's oceans, the humpback whale. As you read, look for important ideas about the humpback as well as the details that help explain those ideas.

Now read "Graceful Giants of the Sea" and complete the worksheet.

If you don't have a copy of the worksheet, click "Graceful Giants of the Sea" Worksheet. Then print out the page or copy the instructions.

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The humpback whale is neither the biggest nor the smallest type of whale. Adult humpbacks measure 40 to 50 feet when fully grown. Size is not the reason people find humpbacks so interesting, however. With their great leaps, mysterious songs, and friendly nature, humpback whales are among the most fascinating creatures in the sea.

Humpbacks belong to a group of whales called baleen whales. Instead of teeth, these whales have hundreds of thin plates called baleen in their mouths. Humpbacks mainly eat small sea animals, such as krill, shrimp, and small fish. When a humpback finds food in the ocean, it opens its mouth wide. Hundreds of gallons of water rush in. Then the whale uses its baleen like a strainer, pushing the water out of its mouth and trapping the food inside.

Humpbacks are world travelers. They swim thousands of miles in their yearly migrations, often moving in groups called pods. They can be found in all the world's oceans. Humpbacks spend the summer in cold waters, where they eat a great deal. During the winter, they move to warmer waters and eat very little. In these warm waters, female humpbacks give birth to their babies, or calves.

Humpbacks are amazing acrobats. Their flippers, which are about 15 feet long, are the longest flippers of any whale. Humpbacks can use their flippers to propel themselves straight up into the air. Seeing a 30-ton whale lift its whole body out of the water and then come splashing down is a truly awesome sight!

Many kinds of whales make songlike noises, but the songs of the humpback are the most complex. These songs can be heard for miles underwater. They are made up of patterns of notes. The notes may be low moans and groans, or high chirps and cries. A song pattern usually lasts 15 to 30 minutes. Patterns are repeated over and over again, sometimes for more than 20 hours! No one knows for sure why the humpback sings. However, humpbacks are famous for their strangely beautiful songs.

Unlike many other wild animals, humpbacks seem unafraid of people. In fact, humpbacks sometimes seem as if they are curious about people. They've given plenty of breathtaking shows, leaping out of the water right in front of whale-watching boats! If you've ever seen a humpback, you know what a thrill it is. If you haven't, perhaps someday you will have a chance to watch one of these graceful giants of the sea.

When you finish the "Graceful Giants of the Sea" Worksheet, use Rate Yourself to judge how well you did on this Reading Journey.

If you don't have a copy of Rate Yourself, click Rate Yourself. Then print out the page or copy the instructions.

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