Sharks. Visit for thousands of books and materials. A Reading A Z Level Q Leveled Reader Word Count: 1,376

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1 LEVELED READER Q Written by Kira Freed Illustrations by Cende Hill Sharks A Reading A Z Level Q Leveled Reader Word Count: 1,376 Visit for thousands of books and materials.

2 Written by Kira Freed Illustrations by Cende Hill Photo Credits: Front cover, back cover, title page, pages 4, 5, 6, 10, 11, 12, 15, 17, 22, 23: Digital Stock; page 16: Dr. Mathew Gilligan, National Oceanic and Atmospheric Administration/Department of Commerce; page 21: William B. Folsom, National Oceanic and Atmospheric Administration/Department of Commerce Sharks Level Q Leveled Reader 2002 Learning Page, Inc. Written by Kira Freed Illustrations by Cende Hill ReadingA Z TM Learning Page, Inc. All rights reserved. Learning Page 1630 E. River Road #121 Tucson, AZ Correlation LEVEL Q Fountas & Pinnell N Reading Recovery 21 DRA 30

3 Table of Contents Introduction...4 Physical Description...7 Eating...10 Reproduction...14 Shark Attacks...15 Strange Sharks...17 Shark Survival...21 Glossary Blue shark Introduction Sharks have lived in the world s oceans for more than 350 million years. They even lived before dinosaurs walked on Earth. There are more than 350 kinds of sharks. They can be found from the equator to the poles, and from shallow seashores to the deepest waters. Sharks are possibly the world s most successful hunters.

4 Southern stingray Sharks are fish, but they are different from most other fish. Sharks have no bones. Instead, their skeletons are made of cartilage, which is the same material that forms our outer ears. This makes sharks very flexible and light. They also do not have scales on their skin, as most fish do. Instead, they have rough skin. The closest relatives of sharks are skates and rays, which are flat, diamond-shaped fish. They also have skeletons made of cartilage. 5 Sharks are the great hunters of the world s oceans. They have an excellent sense of smell and are able to see well in poor lighting. Sharks can sense the slightest movement of other animals. They are especially sensitive to the sounds and movements of injured animals. Sharks can even sense tiny bits of electricity, which are produced by all living things. Sharks can sense fish buried under the sand on the ocean bottom. People have even found shark tooth marks in electrical cables that run along the ocean floor. 6 Mako shark

5 whale shark great white shark Size variation in sharks and comparison with human spined pygmy shark Physical Description Sharks come in many sizes. Some dogfish sharks are only a few inches long. The whale shark is the largest fish in the world. It can grow as long as two buses and can weigh as much as three elephants. Most sharks have powerful, streamlined bodies to help them swim quickly and catch their prey. They have pointed noses and long, slender bodies that look like torpedoes or airplanes. 7 Illustration of a swell shark. The dotted line indicates the shape of the shark s belly when it is puffed up. 8 Most large sharks are so fierce that they have few natural enemies. Smaller sharks are often protected by camouflage patterns that help them blend with their surroundings. Even large sharks use camouflage. They are dark on the top and pale on the bottom. This helps disguise a shark s outline so it is harder to see. Some sharks, called swell sharks, protect themselves from attack by puffing up their bodies with air or water. This makes them appear larger and helps to keep predators away.

6 dorsal fin second dorsal fin caudal fin anal fin pelvic fin pectoral fin Sharks swim by swinging their tails from side to side. They have fins on the top, sides, and underside of their bodies. Fins help sharks steer, turn, and keep their balance. The dorsal fin, which sharks use to keep upright, sometimes sticks out above the water. This can let humans know a shark is present. 9 Eating Most sharks mouths are located on the underside of their heads. The shape of a shark s teeth depends on the kind of food it eats. Most sharks have many rows of teeth in their mouths. When one tooth breaks off, the one in the row behind it moves up to take its place. Sharks teeth break off easily. Many sharks have jaws that fit loosely in their heads. Their jaws can swing forward to bite prey, and then pull the food back in toward the shark s stomach. 10 Do You Know? A shark may wear out and regrow a thousand teeth during its lifetime. Great white shark

7 Do You Know? A great white shark can swallow a whole seal in one gulp. Great white shark Most sharks are fish eaters. Many of the largest sharks eat sea lions, dolphins, and other sharks. These large sharks have triangular teeth with edges as sharp as knives. The teeth point backward to help the shark catch and hold onto its prey. They also help the shark tear its prey into chunks that it can swallow. 11 Other sharks, such as cat sharks, eat clams, crabs, and lobsters. These sharks have flat teeth for crushing and grinding shells. The huge whale shark has no teeth at all. It eats tiny ocean plants and animals, called plankton, that float and drift on or near the ocean s surface. It swims with its enormous mouth open, swallowing water as it moves along. Special filters in its gills catch the plankton and let the water flow through. 12 Do You Know? The word plankton comes from the Greek word for drifting. Plant plankton are called phytoplankton. Animal plankton are called zooplankton. Whale shark mouth

8 Cling fish attach themselves to a shark s body. Many sharks are accompanied by pilot fish. These small fish swim close to sharks, waiting for scraps of food to float by when the shark feeds. Other small fish, called cling fish, cling to the shark s body and keep the shark s skin free of parasites. Cling fish also feed on leftovers from shark meals. These fish are safe around sharks because few of their predators dare to come near a shark. 13 A dogfish egg case Do You Know? Unlike humans, baby sharks are not helpless when they are born. They are able to hunt for food right away. 14 Reproduction Baby sharks are called pups. Most kinds of sharks bear live young. A few kinds of sharks, including the dogfish, lay eggs that hatch a few months later. Each egg is protected by a leathery egg case while the shark is developing. The cases are rectangular, and many have stringshaped ends that attach to seaweed. Some people call shark egg cases mermaids purses. Most sharks have fewer young at a time than other fish do. Sharks usually have only one or two pups at a time.

9 Shark Attacks Sharks have a reputation for being terrifying, but most sharks do not attack humans. In fact, bees kill more humans each year than sharks do. Only a few kinds of sharks are known to attack humans regularly. One of these is the great white shark, which can even attack small boats. Great white sharks usually eat large animals, such as sea lions and other sharks. Great white shark 15 Do You Know? Of the millions of people who swim in oceans every year, only about a hundred are bitten by sharks. Nurse shark 16 Other kinds of sharks also have attacked humans. Even small sharks may bite if disturbed or surprised. Shark attacks are usually the result of people swimming in shark territory. People who swim too close to a shark or who startle it are in danger of being attacked. Many scientists think that sharks confuse swimming humans with their normal prey. Many shark attacks involve the shark taking one test bite and then swimming away when it realizes that the human is not its normal prey.

10 Strange Sharks Hammerhead shark One of the strangest looking sharks is the hammerhead shark. It has a flat head with large lobes on each side. The eyes and nostrils are positioned on the ends of these lobes. Its strange head shape helps the hammerhead see around and behind it. There are nine kinds of hammerhead sharks. 17 Cookie-cutter shark Close-up of mouth of a cookie-cutter shark 18 The cookie-cutter shark is a very small shark that has a rounded mouth and extremely sharp teeth. It takes circular bites out of seals, whales, and dolphins. The bites do not kill the victims, but they leave round scars in the shape of cookies. The cookie-cutter shark also has skin that glows dimly in the darkness of the ocean.

11 Wobbegong shark The wobbegong shark is a master of camouflage. It is covered with colorful splotches and spots that help it blend in with seaweed, sand, and pebbles on the sea floor. The wobbegong also camouflages its body shape. It has fringes of skin around its head and mouth that resemble the shape and movement of seaweed and coral. A curious crab, lobster, or fish may think these flaps of skin are plants that is, until it becomes a tasty meal. 19 Thresher 20 The thresher has a whiplike lobe at the top of its tail. When a thresher finds a group of fish, it swims in the middle of them and moves its tail around violently. Many fish are either killed or stunned, which makes them easier to capture and eat. The thresher s tail makes it a very strong swimmer. It can leap completely out of the water.

12 Shark Survival Shark fishing boats Sharks are hunted for many reasons. Sharkskin is used to make shoes, belts, and wallets. Shark oil is used in many cosmetics. Shark teeth are used for jewelry. Shark meat is eaten by many people. Shark fins are used in a popular soup, and the shark usually dies when its fin is removed. 21 Great white shark 22 Many kinds of sharks are now in danger of extinction (being completely wiped out). People often do not protest when sharks are killed because sharks are thought to be mean and dangerous. However, most sharks are dangerous only when they are trapped and fighting for their lives.

13 Gray reef shark Sharks do not reproduce nearly as quickly as other fish. When they are killed, it takes much longer for their numbers to increase again. Sharks are a top predator, meaning that they are at the top of their food chain. They are an important part of the balance of life in the world s oceans. They have as much right to exist as any other animal. 23 Glossary camouflage an adaptation whereby many sharks and other animals blend in with their surroundings in order to be less visible to predators (p. 8) cartilage an elastic tissue that makes up the skeletons of sharks, rays, and skates (p. 5) dorsal fin the fin on the top of a shark s body (p. 9) extinction the process by which an entire group of animals or plants dies out (p. 22) plankton tiny plants and animals that live on or near the ocean s surface (p. 12) 24