Sharks are the oldest fish on the planet. They have been swimming in the Earth’s oceans for more than 400 million years. How have they survived for so long? Perhaps it is their special body and super senses!
The shark’s body contains a special skeleton. This skeleton isn’t made of bone. It is made of cartilage, which isn’t as hard or stiff as bone. Cartilage is lighter than bone, too. This means a shark can move faster in the water. Also, the shark’s skin is not covered in scales like other fish. Shark’s skin is covered with special teeth-like scales. These scales are called denticles. Denticles help a shark swim fast and protect it, too.
Sharks have super senses. First, sharks have night vision. They can find prey in dim or dark water. Next, sharks have an amazing ability to smell. Two-thirds of their brains are used for their sense of smell. Sharks can smell a drop of blood one-third of a mile away. That’s about six football fields! These senses make sharks super hunters and have helped them survive.