Zoom Sharks. Sharks are amazing fish that have been around since long before the dinosaurs existed. They live in waters all over the world, in every ocean, and even in some rivers and lakes. Unlike bony fish, sharks have no bones; their skeleton is made of cartilage, which is a tough, fibrous substance, not nearly as hard as bone. Sharks also have no swim bladder (unlike bony fish). SIZE There are many different species of sharks that range in size from the size of a person's hand to bigger than a bus. Fully-grown sharks range in size from 7 inches (18 cm) long (the Spined Pygmy shark), up to 50 feet (15 m) long (the Whale shark). Most sharks are intermediate in size, and are about the same size as people, 5-7 feet (1.5-2.1 m) long. Sharks have a variety of body shapes. SKELETON Sharks are a type of fish that have no bones, only cartilage.
Sharks belong to the group of fishes called Elasmobranchii, which also includes the rays, skates, and ratfish. Sharks may have up to 3,000 teeth at one time. What Is Energy? Science Netlinks: Lesson Index. Animal Games for Kids - Kids Corner - Sheppard Software. Interactive Games, Puzzles, and Quizzes!--National Geographic Kids.
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