The great white shark gets its name from its white belly. Its back is bluish gray. This countershading helps the shark catch prey by surprise. Fish looking down at a great white see only dark ocean water. Fish looking up see only light from the surface. The great white's body is covered with flat, pointed scales called dermal denticles. These scales are packed together tightly. They protect the great white from injury and help it move smoothly through water. The great white can grow to be 21 feet (6.4 meters) long, but it averages between 12 and 16 feet (3.7 and 4.9 meters).